Tach and DDIS

[zero2080]

Alright so first off the boat is 89 Wellcraft Classic 170, Mercruiser 3.0l Alpha One

At WOT my Tach will read ~5600RPM well over my suggested 4600 I am trying to narrow down the cause.

But anyway I was reading manual and was wondering if I read correctly that the DDIS ignition wont let the enigne RPM go over 5000 is that correct in my understanding so am I safe in going WOT till I determine my cause of improper reading at tach.

 

[Fishermark]

Re: Tach and DDIS

am I safe in going WOT till I determine my cause of improper reading at tach.

In the words of the immortal Clint Eastwood: "Do ya' feel lucky?" (I won't throw in the "punk" )

It seems to me a safer course of action would be to verify whether or not you are actually getting an improper reading at the tach. Do you have a handheld gauge / tach you can use to check?

 

[zero2080]

Re: Tach and DDIS

No I dont a test guage Im not sure if there are multiple ways to figure out the problem or not. But sometimes the guage will read ~2000 when the boat is of and not energized, and I want to say I remember last year the guage would read high then sometimes lower but I could be fooling myself. Out of curriosity though is that true of the DDIS system that it prevents the engine from over reving?

 

[Fishermark]

Re: Tach and DDIS

I am mainly responding to put it back on the top as I don't know the answer to your question. Even if it is designed to prevent over reving - things sometimes don't work like they're supposed to... still a good idea to verfiy your actual RPMs.