When engine is running the needle jumps up and down about 400 rpms very erratic. I was concerned that I would toast my engine so I installed a mechanical gauge and found out I have great oil pressure. its on the side of the distributor on non b20 accords BUILD THREAD. Tach check is also correct, if the tach is erratic, then the rectifier is probably going bad. What’s next on your list of diagnostics? I was told it is likely a voltage regulator problem. The boat chinewalks very slightly from 70-75 mph but the boat is steady from there to wot. The tachometer runs fine for the 20 minutes of operation and then the needle swings wildly up and down the rpm scale. Here you will find a large collection of original gauges and clusters* that are just waiting to be retrofit into your vehicle. Step 2 - The idle air control motor (valve) is responsible for controlling the engine idle speed, if this part fails or becomes weak the engine idle speed could become erratic, additionally, this condition may or may not trigger the MIL (check engine, service engine soon light. Hermann Lazy Jack 32, 1979, Stockton Springs, Penobscot Bay, Maine. Doing, am grilled given all. ) become oxidized with time, and this leads first to erratic readings and then to no readings. I feel like the motor needs to be at about 5500 rpm. 0's - same thing. he tells me that he had run boat under power for around an hour, at around 26-2800 RPM, with no signs of issues. Boat gas gauges are notoriously unreliable. horsepower (for example, 3400 rpm). My Profile My Preferences My Mates. It had a 6k tach and you'll never reach that. Ive dismantled the cluster and there are 3 pins behind tachometer which is power, ground and signal - I know which one corresponds to which. I've exactly the same problem ,the tachometer. Tips, comments, help welcomed. the problem is probably in your tach or the wiring to it. On his advice I did this to the tachs on my boat's lower helm and both now read accurately. Sea Ray 205 Sport Manual Online: Important Gauges, Tachometer And Hourmeter, Oil Pressure, Water Temperature, Voltmeter And Fuel Gauge, Magnetic Compass. Example: A boat with "405" as the last digits indicates the boat was built in 2004, but it is a 2005 model boat. The last owner had a 160 deg. The 675 is a big, heavy boat with a deep vee that needs some tough ponies on the back to get it up and moving. If voltage isn't coming up, it probably is bad. com ,the Leading Trading Marketplace from China RPM Boat Tachometer 6000. If your tach is consistently 200RPM off, I doubt the crank position sensor is the culprit. Looking to redo the gauges on my STV. HOW FAST SHOULD MY BOAT GO 2005 322 Cruiser Erratic Gauges By Lonerifle,. Find our best fitting temperature gauges for your vehicle and enjoy free next day delivery or same day pickup at a store near you!. It is often said that for an engine to run you need fuel, air, and spark. Location: The tachometer should be located at least 18"fromamagneticcompass. The tach i'm looking at is a standard Teleflex unit. 11 to 15 RVP (cool to cold weather) fuel will change from liquid to a vapor at lower fuel temperature than 8 to 10 RVP (warm to hot weather) fuel will. This will neither damage a Faria® tachometer nor affect accuracy when not transmitting. Traced all wiring and connectors for continuity and all is good. This photo shows two 24" diameter by 20' long plastic culverts in the boat. When one of these goes bad it can make the speedometer and tach go all over the place and also just. denisefiedler. The tachometer also uses this information to inform its reading. The first tinytach I had used a coax wire with a grounded shield. Turning things off makes them work again. As part of the upfit I have a new vdo vision series tach. Bad Stator Fix--Don't Buy a New Stator for Your Engine! Create a Battery-op Ignition System for Less Than $50: The cost of a new stator can be hundreds of dollars. The computer is not able to determine if the throttle is closed or not. 2000 Grand Prix GT 3. The tachometer is driven by the tachometer signal, but it also operates from the boat 12-Volt battery, and thus any variation in the connection of the tachometer to the 12-Volt power. Spark comes from the ignition system. Talk with your dealer and the service manager, explain your situation, and ask for a test ride with a tech. Most aftermarket fuel senders use a rotating float arm and resistance cards to measure the amount of fuel in a tank which can lead to erratic pointer movements. Erratic oil pressure in late model engines was one such festering issue in the late 1980’s, and it continues to show up on our plates today as well. Drive temp gauge installation instructions Model Number: DCSDT (color) The Livorsi drive temp gauge kit easily installs into most outdrives. A boat owner running a boat without a tachometer handicaps himself significantly. When I'm accelerating and get to required speed my RPM gauge either drops and steadies or jumps up then steadies back. We recommend upgrading. Boat Data. 00 • All clusters LED upgrades vehicle dependent $85. Motor is at 2000 rpm +/-, tach jumps up to maybe 3000, down to 1500, back up - after a minute or so reads fine again and stays there. Erratic tachometer boat. When the throttle is advanced one of the engines will show about a 1000 RMPs less and fluctuate. The tach i'm looking at is a standard Teleflex unit. Fuel gauge behaves erratically. This revolutionary design comes with many benefits! This is ideal for applications where a conventional swing arm will not fit due to clearance issues. Also, keep in mind my fuel gauge ALWAYS says empty, and since my fuel tank is almost full right now I want to wait until its closer to empty before I start removing the fuel sender unit to see what the problem is. Automotive tachs will not hold up won't work right. :mad: Anyone happy/unhappy with what they are using currently?. Excess Fuel Consumption. Forget about politicians, used car salesmen, and stockbrokers--if your boat is bigger than a canoe and smaller than the QEII, chances are it's lying to you right now. At about one-third trim travel, the switch should open and the meter should show no continuity. My tach was bad. More modern digital, NMEA-networked, and multifunction gauges may be all the buzz, but the reality is that most boats are still equipped with the same analogue set-ups that have been in use for. The vast majority of recreational boats in service today are still using analogue instrumentation systems. The boat sat for over a year without even running, then I ran it last fall. where the wires come back up they rubed against the dog house that is covered with a auluminum type cover. A transistor or two and a few capacitors and resistors are all that is needed. Low Engine Power. Intellitronix is an electronic digital accessories company based out of Eastlake,Ohio. I was concerned that I would toast my engine so I installed a mechanical gauge and found out I have great oil pressure. I've exactly the same problem ,the tachometer. Get the job done with the right part, at the right price. According to Mercury you can add SC 100 system link analog gauges that will convert the digital signal so you see it on an analog gauge like the SC 100, please correct me if I'm wrong. Technical Discussion. Accompanying the erratic tachometer readings will also usually be very poor battery charging current output, if the rectifier is the cause of the problem. I own a boat with twin 1993 Merc 200's. ELECTRONIC FUEL GAUGES. Your browser does not support frames. The boat comes out of storage this weekend so it's time to tap into the wealth of knowledge on WC. To use the tachometer, merely point it at the propeller from behind, looking through the propeller arc. Normally with my setup I can't get more than 5200 rpms WOT. It categorizes areas of possible malfunction, likely cause and recommended action to bring your new, rebuilt or used Twin Disc marine transmission back to proper operation. How do you get tachometer from 1970 chevelle to work with hei. The gauge is in my buddies Alpina boat. Ive dismantled the cluster and there are 3 pins behind tachometer which is power, ground and signal - I know which one corresponds to which. When I'm accelerating and get to required speed my RPM gauge either drops and steadies or jumps up then steadies back. At first I was thinking the sending unit has gone bad, but when the car is turned off the gauge only drops to half instead of all the way down. This gauge has a white and black face with a chrome bezel, and the mounting hole size is 3 1/4" in diameter. Pressure transducers are the components most vulnerable to damage from pressure spikes. 0 inch VDO with no labels on it and has 4 terminals (12V, Sense and 2 x earths). Brought down a certified verado tech did a diagnostic test and everything is up to spec. The 4th one was plain dead. As part of the upfit I have a new vdo vision series tach. An engine's vacuum readings can tell an awful lot about its running parameters, provided you know how to read the gauge in the first place. When I'm accelerating and get to required speed my RPM gauge either drops and steadies or jumps up then steadies back. Haven't had the problem ever. It is often said that for an engine to run you need fuel, air, and spark. Erratic depth readings There can be several causes for erratic depth readings. This condition is only present on the SmartCraft System Tachometer, Monitor, or SystemView when engine is equipped with a digital trim sender, and does NOT affect analog trim gauges. With a full range of Weather Stations, Forecasters, Thermometers, Rain Gauges, UV Sensors Wind Vanes and Barometers from ranging from £20 - £400 Oregon Scientific has everything for the casual observer to the serious weather enthusiast. This is the tachometer I used http. 65 6 HP 1986-2005 4500-5500 2. Winterized it and it sat through the winter. It is however important to ensure correct alternator belt tension is maintained. 8 volts across the alt gauges 2 rear terminals (just tap it or your test leads may start to smoke:) the pointer should jump and the alt gauge is most likely good. Accompanying the erratic tachometer readings will also usually be very poor battery charging current output, if the rectifier is the cause of the problem. If you are familiar with your engine’s normal idle, compare that to its current RPMs. We’ve put together this quick-guide to reading your vacuum gauge to help you identify potential mechanical or tuning issues more quickly. Vehicle Speed Sensor Description & Related Information. I don't know how your tachometer works. Someinterference (erratic operation) may be noticed on the tachometer during radio transmissions. The world’s easiest-to-use fishfinder, HOOK² 7x SplitShot features Autotuning sonar, Broadband sonar and DownScan Imaging™, plus a simple GPS Plotter -- all at a price that is easy to afford. I 'fixed' the tach on my last boat by doing this. When one of these goes bad it can make the speedometer and tach go all over the place and also just. Hey guys I need a little more help here if possible. Intellitronix is an electronic digital accessories company based out of Eastlake,Ohio. Have someone watch the tachometer while you wiggle the wires on the engine side. In general the speedometer and tachometer are used to measure and display speed but to be specific they differ in what they represent ie Speedometer displays the speed of the vehicle whereas tachometer displays the speed of the engine. Unfortunately, most vacuum gauge manufacturers don't provide easy-to-follow instructions and diagrams to help users interpret gauge readings, rendering the gauges themselves virtually useless. denisefiedler. Chevy gauges that are easy on the eyes and blend in with your car's trend are a lot easier to pay attention to. I got the new tach installed and splashed the boat for the first time this year, this past weekend. Accompanying the erratic tachometer readings will also usually be very poor battery charging current output, if the rectifier is the cause of the problem. Outboard Motor Tachometer Tach/Hourmeter. ) The gauges will immediately start working again. The prop that is on the boat is a Solas 3 blade stainless that is 13x21. Traced all wiring and connectors for continuity and all is good. Turn the power off. John and Linda 'Escapade III'. I "fixed" tach's on 4 boats this year (all Faria). I put the new distributor on, but am still having the same problem. 99% of the time my tach reads fine but on rare occasion it will suddenly jump up and down. What’s next on your list of diagnostics? I was told it is likely a voltage regulator problem. The Honda AquaTrax F-12X performs well and it’s very stable even when it encounters waves up to 2-4 foot. Fortunately, marine gauges are not complicated in their. Throttle Position Sensor Failure. If that bullet connector has come loose and/or corroded or one of the wires at the back of the tach is loose/corroded you can get erratic tach behavior. Checking Boat Fuel Gauges And Fuel Sending Units. Why not choose from one of my many books to help you fix your problems. There are 2 sensors on the engine that sent a signal to the computer and speedometer and tach. *Honda 40 & 50 (2005 & older) hp models may require module (Honda P/N 06383-ZV5305 if tachometer is erratic between idle and 1800 rpm. Erika was an erratic, rather fickle tropical storm that seemed to be heading right for us, so the manager at River Forest had to make a call – hurricane mode or not? And he had to do it in time to get all the boats that would be coming in hauled out and prepped. Some boats may need a lower value if control is not smooth. Should be a sending unit on top of the timing chain cover, it connects to either a blue or green wire which runs back to the fuse blockon my car i had them flip flopped with the water temp sensor and t was reading all funkymake sure you got em on the right sendergoes into the car through the fuse block and same green or blue on inside connects to the tach. Fuel gauge behaves erratically. Want Answer 0. tachometer, first determine your engine's shift point for max. By John Payne. Drive temp gauge installation instructions Model Number: DCSDT (color) The Livorsi drive temp gauge kit easily installs into most outdrives. Sign in to follow this. " Bjmillic1 - GA: 06 Triton TR21X 06 250 Merc. The tachometer should be connected to the power lines dedicated to the engine instrumentation. I have a 2006 Bass Tracker Pro team 190 tx. The fuel level shown is a calculation based on the sending unit input. If you are familiar with your engine’s normal idle, compare that to its current RPMs. Add to Wishlist. Bad Stator Fix--Don't Buy a New Stator for Your Engine! Create a Battery-op Ignition System for Less Than $50: The cost of a new stator can be hundreds of dollars. Forget about politicians, used car salesmen, and stockbrokers--if your boat is bigger than a canoe and smaller than the QEII, chances are it's lying to you right now. Flatscreen? Check. The speedometer has always worked until this year and the tachometer has never worked. Connect a wire to the tachometer stud marked "GND" (ground) and secure with a nut and lock washer. Also, if the vehicle speed sensor signal was fluctuating, the cruise control would have problems maintaining a constant speed. When under way the needle will stabilize at a normal reading of 3,000 to 3,500 then spike repeatedly to around 5,000. AIR CORE GAUGE OPERATION Short sweep air core gauges function from resistance or voltage inputs. RPM's erratic at times Thread in 'Nitro & Tracker Owners' started by Kenny Guess, Jun 19, 2011. The Strike King KVD Square Bill is designed to the specifications of BassMaster Classic Champ Kevin VanDam. Seems like every boat I've had has had this. Some interference (erratic operation) may be noticed on the tachometer during radio transmissions. Rough Engine Idle. tachometer, first determine your engine's shift point for max. Support this group and join the ads-free movement to make online. Do not ground on the frame, do not use a common ground wire. I'm replacing the multi-tach with two VDO tachs tomorrow (removing the useless speedometer). If the oil is cold or warm the control head still regulates it at spec. For example, I would keep the car running at 4K then the tach meter bounce back and forth from 1k then 4K the whole time I'm driving the car. Something that is known good. Merc XR6 150 problems, mechanics i need your help!!! my tach was erratic, and inaccurate. Erratic Reading. "Be number of poles on the alternator can be determined by checking the Faria* Outboard Tachometer Application table. If the oil is cold or warm the control head still regulates it at spec. Accompanying the erratic tachometer readings will also usually be very poor battery charging current output, if the rectifier is the cause of the problem. Three large square gauges provide a functional and intelligently laid-out reading of the engine’s speed, fuel data, trim and tacho. I tried tapping the 12v supply to the signal to provoke a response but it cause erratic behaviour and I dont want to risk damaging it anymore. 3/ 4" long. (make sure that you replace it with a marine duty tach. ) become oxidized with time, and this leads first to erratic readings and then to no readings. 00 • 04-06 Nissan Quest with display. Services/Products GM Instrument cluster repair. A faulty sending unit will not cause fluctuation but a faulty gauge will. I have owned numerous boats and been in friends boats and have never seen tach's this bad. Low Voltage symptoms are weak erratic firing of cylinders. We also supply a large inventory of Detroit Diesel engine parts and subassemblies with online ordering. We have Porsche Parts for 911, Carrera, 914, 356, 944, 924, 928, Boxster and more. It's possible you have a bad ignition switch. I have had a lot of boats in the past with this problem. But you also need compression and the correct spark timing. To use the tachometer, merely point it at the propeller from behind, looking through the propeller arc. If yours is erratic it is probably bad. Made with the same design, mold, and dimensions as the Original Hot 'N Tot, the Madflash moves with that classic Hot 'N Tot erratic diving action and side-to-side swagger for an irresistible profile in the water. when it starts acting up it's basically like a bad miss but then when it's not under a pull and the tac stabilizes it runs fine also at an idle the oil pressure drops to nothing its full of oil no tappet noise or knocks. Location: The tachometer should be located at least 18” from a magnetic compass. About 3 months ago she developed a miss. com ,the Leading Trading Marketplace from China RPM Boat Tachometer 6000. de installation manual 77 nyrhslideshare. david hill. My first new boat, and my first I/O. But a problem where your speedometer drops to zero randomly can be very hard to pin down. The Honda AquaTrax F-12X performs well and it’s very stable even when it encounters waves up to 2-4 foot. Boat gas gauges are notoriously unreliable. I went around the boat with my multi meter, checked all the connections under the dash and the fuse panel, nothing out of the ordinary whatsoever. I just replaced the oil pressure sensor as it was pegged out at the max and ran into the same problem on my mada. This ammo’s main objective is to make sure that people can access the best and cheap ammo for the 9mm concealed carry. com, Well installed new on and it still reads full up and the new sender ohm chk is OK. Fixes for 12V Signal Style Tachometers If your tachometer needle is bouncing or reading too high: Problems with Early 12V Signal Style Tachometers If your tachometer needle is bouncing or reading too high: If the car’s tachometer RPM reading is too high when the engine is running, or the tachometer works OK to a certain RPM,. The gauge is in my buddies Alpina boat. 2006 Dodge Ram - Tach or speedometer erratic (tach goes fully clockwise). The boat started fine and all other accessories operate but for some reason the dash has no power. MERCRUISER HORN WARNING SYSTEMS Page 4 / 10 90-898301003 JUNE 2007 1995-Current 5. By John Payne. Example: A boat with "405" as the last digits indicates the boat was built in 2004, but it is a 2005 model boat. Connect an ohmmeter to the switch bullet leads. Replacing the MMDC will erase the hours. So, I've been on the water with my '99 Sportster 1800 a lot over the past few days. When one of these goes bad it can make the speedometer and tach go all over the place and also just. The key is understanding what your gauge is trying to tell you. 0 and 5 speed tranny. Checking Boat Fuel Gauges And Fuel Sending Units. Accompanying the erratic tachometer readings will also usually be very poor battery charging current output, if the rectifier is the cause of the problem. de installation manual 77 nyrhslideshare. Meter should show continuity with drive unit in down position. There is a pink wire that goes down to the transmission Her. I spent considerable time comparing the VMSpc gauges like oil pressure, air pressure, alternator voltage and tachometer to the console gauges and both sets are preforming exactly the same. Holley offers a variety of fuel pressure gauges, depending on use. I started the car and the tach went to roughly 4000 after making sure that the tach connection was solid from the new kit. Connect opposite end to the boat's electrical ground, generally available in several locations at or near the instrument panel. Welcome to the Classic Boneyard. Flatscreen? Check. I can turn things back on and the gauges will continue working for a while but will eventually fail. Set the desired RPM by turning the adjust knob on the back of the tach, the pointer will move. 2L Horn Output Possible Cause Corrective Action Engine Usage Available For Consumer Solid horn on key on, but goes off when oil pressure switch. This is a general guide which will list symptoms for 944 starting and running problems and common causes of those problems. If the float sticks in one position due to mechanical deficiencies, a bump in the road may jar it loose, and normal function returns. On the back of most tachs is a switch that allows the tach to be used on 4/6/8 cylinders, I moved that switch back and forth to clean the contact internally and then put back to the original setting. Jun 19 I had the exact same problem with my boat. Repair Cost $229 - 2006 Dodge Ram Tachometer. Precision stamped and balanced mechanical advance weights eliminate erratic timing. When the dashboard lights in your vehicle malfunction or cease to operate, the resulting effects can range from being a mere annoyance to posing a safety hazard. Alternators and Outboards Charging Systems. 120 litre (APPROX) FRESH WATER TANK. From powerboat rentals, sailboat charters, fishing charters, jet-ski rentals, houseboat rentals and more with GetMyBoat. Some interference (erratic operation) may be noticed on the tachometer during radio transmissions. If out of range, the sensor needs to be replaced. Location: The tachometer should be located at least 18” from a magnetic compass. Let us know what you think! Please use our Contact Us page for issues that require a more immediate response. The 4th one was plain dead. E xcuse me, sir, have you any idea how fast you were going? That's the question every motorist dreads being asked by a police officer at the side of the road. I changed the the Tach out with a new one and cured the problem. (not finished, but still very useful) Note! A fully charged battery will show no charge under many circumstances. Ranger & B-Series - erratic Tachometer - I have A 94 Ranger XLT Supercab 4X4, 4. " Bjmillic1 - GA: 06 Triton TR21X 06 250 Merc. The boat chinewalks very slightly from 70-75 mph but the boat is steady from there to wot. If you suspect your tach to have this problem, locate the capacitor, carefully unsolder the capacitor, and replace it with a new one. iT GOES FRFOM 1000 TO 5000 RPM. This tach(a teleflex) was installed new last season, along with all new gauges and electronics. If out of range, the sensor needs to be replaced. From this screen you can also change the LCD to metric. If you’re 47 years old, drive a Mercedes or a Corvette, operate your own business, have a net worth greater than $1 million, and enjoy power boats, then it’s not a bad bet that you also own a Trojan International series boat, probably a 10 Meter. These can be fuel injected engines or carbureted engines. Check out our new, complete online catalog for Auto Enthusiast Gauges. Top end was around 48MPH @ 4500 RPM and no gear, and only half a tank of gas. My Gas Gauge Reads Empty When It Is Full Of Fuel One thing I see and hear quite a bit of from customers is that they complain that their fuel gauge is inaccurate or acts very erratically. My boat was purchased from a deceased estate and the tacho has never worked for me. Hi there, thank you so much for connecting with us. Installation 1. Be certain to use stranded, insulated wire not lighter than. de penta ms megarh. Now this summer, It's had this problem of not starting. Why is this happening -- I have learned that caterpillar. For general, non-boating topics please use our "General Discussions" section. Their tech guy gave me a great tip, he says the tach's internal contacts on the engine selector switch (4 cylinder, 8 cylinder etc. Find out what type of fuel is in the boat’s fuel tank. Even the breadboard to build it on and test it are available at Radio Shack. Dolphin Instrument & Gauges are manufacturers of precision, high quality, reliable gauges for the automotive industry. If a tachometer is going bad will cause erratic starting, runs sometimes, dies unexpectedly,sometimes starts right back, don't start at other times, runs great at times, synchronizer will show rpm balanced, yet port tach will show 1200 more rpms, than starboard which by ear isn't so, I've replaced coils, dist modules, shift switches, etc I'm. Get the best deal for Other Boat Accessories & Gear from the largest online selection at eBay. A lot of people don't realize their boat has two tanks. I seem to be in the same boat as you with my Tach gauge on the QX. Stop when it reaches the desired shift point. For example, I would keep the car running at 4K then the tach meter bounce back and forth from 1k then 4K the whole time I'm driving the car. My dad has a bottom of the line Cutter with a Faria tach and it works fine. Organizations across Oregon recognize the value in restoring Willamette River habitats and have provided funding to help Salem accomplish their restoration goals. (This will result in PerfectPass disengaging). I went back to the instructions and they said a bad ground often causes erratic readings. Call 801-221-1460. Fuel gauge behaves erratically. in it moves around between roughly 160 and 215. Browse your favorite brands affordable prices free shipping on many items. It's seams to me I have a low voltage issue but don't know whats causing it. Take a small screwdriver and turn the screw back and forth a couple of times, finally returning it to the original position. In gear, with my foot on the brake, the idle would surge from 600-900, maybe a 2 second cycle. The other would be to purchase one of our 240-33ohm scaled gauges and the matching #3262 sending unit, or if this unit will not fit your specific tank type, a similar 240-33ohm fuel level sending unit from your tank manufacturer. I changed the the Tach out with a new one and cured the problem. When I'm accelerating and get to required speed my RPM gauge either drops and steadies or jumps up then steadies back. I put the new distributor on, but am still having the same problem. Old No7 is VIP+ Member. What would you do to improve our website? We're always looking for ways to improve JEGS. Additionally, if the engine turns more quickly, the change in the magnetic field becomes more radical, generating higher voltage. Do not ground on the frame, do not use a common ground wire. To use the tachometer, merely point it at the propeller from behind, looking through the propeller arc. All info subject to change, correction, frequent updating. The chart below shows the areas boat owners have most common questions on when trying to troubleshoot why their Twin Disc ® marine transmission MG5111A underperform. This will neither damage a Faria® tachometer nor affect accuracy when not transmitting. Title: Untitled-3 Created Date: 5/9/2006 12:00:36 PM. Aren't the Point A and Point F tests doing exactly that? I know the point F test is a test to see if the voltage output is greater than or equal to the battery and the point A test is taking point A and jumping it to the positive battery post. There are many reasons why you could have an faulty ECU. Find outboard engine specs, special financing, accessories, and Honda Outboard Motor dealers near you. However, most of our inventory is a balance of new boat parts, new "old stock" marine parts and genuine replacement boat parts made by the original manufacturers. This will neither damage a tachometer nor affect accuracy when not transmitting. So, I've been on the water with my '99 Sportster 1800 a lot over the past few days. If out of range, the sensor needs to be replaced. John and Linda 'Escapade III'. When the dashboard lights in your vehicle malfunction or cease to operate, the resulting effects can range from being a mere annoyance to posing a safety hazard. Then [the tachometer reading] returns to normal. friend of mine has a 1980's 1GM diesel that is well cared for and in good shape. What/how do I need to check on it? I've heard if it's missing a paddlewheel, that could cause it. ihrsegeltraumbystuis. --The organization of the motor torpedo boat squadron is similar to that of an aircraft squadron in that the squadron, rather than the individual boat, is the commissioned unit. mercury outboard tachometer and speedometer not working? my boat has a 1995 mercury 90HP outboard. alternator gauges in ford and mopar use a different setup and can be checked by applying a large d. have a 76 vette and once I installed the 6A, the tach starts to act erratically. My tach was bad.