Tachometer question

[TightlineT]

I got a new to me boat a week or so ago. The tach seems to hang up around 3200 rpm. I peck on the gauge and it will jump up and seem normal. Sometimes it will read something like 5000 when I'm just barely going and you can peck it down to a reasonable range. I've had my old boat for about 15 years now and this is not normal to me, so should I be concerned enough to change it or is this kinda normal (talked to another guy who is having the same problem)? Also, the boat is a 21' Stratos with a 26 pitch 4 blade prop on a 225 Mercury - what should I expect rpm wise for this setup and what is too much??? I'm kinda slow go, so I'd rather lay out of the pedal than hurt the motor. Thanks for any info

 

[wrechin2]

Depends on what 225 you have. The 225 pro max has a rev limiter @ 6850rpm on most factory boxes. If a 225 3.0L carb it will not have a limiter and if it is a 3L 225 EFI it will have a limiter in it as well but I am unaware of what it is. Most cases if the tac will hang at a rpm and you change the rpm a lot and it stays the same, it is ususally the tac. A stator problem will using cause a hunt where the needle bounces up and down with no rpm change. Just my experiences.

 

[TightlineT]

wrechin2 - 10/10/2011 10:20 PM

Depends on what 225 you have. The 225 pro max has a rev limiter @ 6850rpm on most factory boxes. If a 225 3.0L carb it will not have a limiter and if it is a 3L 225 EFI it will have a limiter in it as well but I am unaware of what it is. Most cases if the tac will hang at a rpm and you change the rpm a lot and it stays the same, it is ususally the tac. A stator problem will using cause a hunt where the needle bounces up and down with no rpm change. Just my experiences.

Thanks James. The motor is a 225 EFI 2003. Most of the time it will accellerate and just stop at around 3200 rpm until I peck it and it seems to go to what I think sounds like a normal rpm. I did notice the other day that it was reading around 2k while I was at idle when normally it reads less than 1000. If it is a stator problem, is that a big problem for the engine or just the tachometer. Thanks for your help.....Jim

 

[SamDHarris]

my tac done the same thing. Mine had an adjustment on the back of the guage that had different settings. I took a screw driver and turned it back and fourth 5 or 6 times and put it back where it was at originally. It has worked fine ever since and that was over a year ago.

 

[Jason F-18]

Mine was reading weird as well. As Sam said, look at the adjustment screw, mine was set to a 5 cyl reading. I turned to 6 and it worked fine. Check the ground as well. A bad ground can cause all sorts of phantom problems

 

[TightlineT]

Thanks for all of the suggestions. I'll have to give it a try. Jim