Tach Jumping

[wired1236]

Have a '07 Reinell 185 w/ Volvo 4.3LGS. Just got it and noticed the tack jumps revs when the engine does not. It isn't missing but rather going from what appears to be the correct RPM to a higher RPM at what looks like at a random interval. Any clues as to what's going on?

 

[Erk469]

Re: Tach Jumping

Check you wiring and and then maybe check the prop to see if it is loose.

 

[b18apwr]

Re: Tach Jumping

I've seen this when the ignitor or ignition control module was failing or had a bad connection.

 

[wired1236]

Re: Tach Jumping

Prop is good and the engine isn't reving up. It definalty is an electrical issue. I'll do some troubleshooting on the wiring and then maybe have to take it in for someone to check the control module. I did install a double battery system, (BEP Marine), that works great. I wired the accessories to it so maybe that's it. I didn't notice it before then but I only had it out once. I will put it back the way it was and try it that way. Thanks.

 

[keelhauled]

Re: Tach Jumping

Mine did this for a while. I found it had a bad/intermittent ground. Did it more at idle than at speed.

May not be your problem, but it's something to look at.

 

[cooter2506]

Re: Tach Jumping

probably only corroded connections on the back of the tack or at the coil.

 

[shdw2001h]

Re: Tach Jumping

My tach did the same thing, I had a screw in the back of my tach starting to back out. That caused the same problem. I had to have the boat running when I adjusted the screw. and now it work fine. Just a thought.

 

[wired1236]

Re: Tach Jumping

Not sure if I found the problem but I think I got it licked.

I had put my accessories on my second battery which includes the tach power lead. Thinking the tach is also connected to the engine which is obviously connected to the starter battery, I decided to put them back on the starter battery thinking that may have caused some sort of voltage loop or something.

Anyway, I put the accessories back on the starter battery and it seemed to fix the issue. I started the engine with it changed back and it jumped at first but then took it out on the water and it never happened again. Damn gremlins. Weird huh? I'll keep playing around with it. Thanks for the ideas!