Motor/Tach question

Need some help please.

My tach is reading more RPMs then the boat has ever turned. First thought it was the hub, and replaced it. That improved the performance, but the tach still reads a little too many rpms and nothing has changed on my set up.

My mechanic said if it wasn't the hub, then I may need a new tach, which is around $167 ... or there about. I've also had someone suggest I check to make sure the tach cable is tightened correctly, and not slipping. I know how to check the cable behind the tach, by removing the dash, but where does the tach attach to the motor?

I have a 2002 Mercury Optimax, and where would I look to find the tach connection?

Thank you in advance for your help.

Danny

I have had the same problem from my '01 Opti. It sometimes reads 400 rpm's too high but, not all the time. If you have a smartcraft guage on your boat you can check the tach. I'm not sure if it's a loose wire or if the tach is just going bad. I know I'm not turning the rpm's it shows at WOT because the rev limiter isn't kicking in. I've chosen not to replace mine since it doesn't happen all the time and I've run my boat so much I can pretty much tell you what rpm it's running by the sound of the motor. Not much help but, just letting you know your not the only one experiencing a problem.
KTB

Danny: What kind of boat are you running? I just got through replacing the tach on my stratos. I had a recktifer (sp?) go out on the big engine that runs the charging system to it and the boat repair shop stuck a white tack in the middle of my console. Black guages with white letters on the mph and systems check tacks and it looked like a sore pe*ker throwed in there. I went off when I seen what he had done. I went to the local stratos dealer and he ordered a factory tach to match the rest of my console. After a month of waiting and one or two they (stratos) sent the dealer which was the wrong ones and didn't fit, I called stratos myself and talked to them. Come to find out they no longer make the same exact tack like I had, so I got one close with black background,white letters, with some gold dash marks in it, and it looks great. Also my old tack went up to 80 and the new one only goes to 70, but hey I am not going to be running that fast to tact it out anyway. I took the white one out and the boat repair shop gave me my money back on it which was right at $100 bucks. The stratos dealer was going to charge around $129 bucks through him, but he is a friend and a good guy, so he told me to run it through his account when I picked it up at the stratos boat plant and paid cash for it in murfreesboro, Tn. since I had so much trouble trying to get it. Ended up costing $45 dollars and I put it in myself which was pretty easy. The only really bad thing about the whole deal was I missed the best part of spring fishing this year not using the boat and running the white tack since it is electrical to get my money back on it...283

Thanks Guys,

I have a Triton TR21, 2002 model, same as the motor. My tach is showing approximately 1,000 RPMs more than it should.

For instance, my boat is not supposed to exceed 5,750 RPMs, and running wide open, my boat turned 5,600 RPMs, and GPSed at 77, although I rarely exceed 70 anymore...LOL.. actually, I don't normally go over 65. BUT, now the tach is showing 6,000 RPMs while only running around 55 or so.

The first time I had the problem, the tach bounced around wildly. The dealership put in a hub, and it was fixed. This time he suggested the same thing before trying a new tach. I put the new hub on this time myself, and the boat showed remarkably better and for the first half a day, it seemed the tach was working correctly. However since then it is back to showing about 1,000 extra RPMs at 55 mph.

A friend suggested since I don't have the digital read out, that I check the tach cable ends to make sure they are tight, and not slipping. As I said, I can find the one behind the dash...LOL.. but where on the motor does it attach so I can check that one?

Also, thanks for reminding me about the rev limiter. I had forgotten about that safety feature to keep the motor from over revving. I do know if the motor is over revved it voids the warranty, and I still have some left, and prefer not to lose it just yet.

Any other help will be appreciated...

Danny

I had a Mercury, sometimes the tach worked sometimes not, sometimes bounced wildly. Had to have the rectifier replaced and no problems after thet.

OK, what's a rectifier?

Pretend I am dumb as a stick when it comes to mechanics, in fact, let's not pretend. *smile*

Thanks,

Danny

Go to bassboatcentral.com and you will find someone who has had the same problem that can help you with that. Excellent site for tech questions.

Sounds like a rectifier to me. Hope yours doesn't go on the water.............lots of smoke and cooked wires. Had mine go on a 150 EFI.... small fire with lots of smoke and a long trip back to the ramp with the trolling motor.

The rectifier is an electronic part, mine was located under the flywheel. Better bite the bullet and get it fixed.