[MAJIC]

Just last week the tach on our 97 Z252 with a 7.4 carb'ed engine started to act up. It would run true and then not - always reading higher then it should and then it would bounce back to where it should be.

Any suggestions?

[WetWilly]

Hi MAJIC, welcome to the club!

When your rpms change, can you tell if the motor is actually changing or does it seem that the tach is faulty and when does this occur, at WOT, while cruising, during take off and what rpms does it happen at?

If it seems like the tach, you may have a connection issue. Start by accessing the back side of the tach where you'll find a small selector dial for setting the number of cylinders your motor has. Note it's position then turn it back and forth to clean the internal contacts then return it to it's original position. See if this fixes your problem.

Now if it's really your motor that is changing rpm, then it gets a little more challenging as it could be in the carb, ignition and even the prop. So let's start with what outdrive do you have? Also, do me a favor, check you prop for any damage indicating a prop strike.

WetWilly

[MAJIC]

Hey WetWilly - thanks for this. The engine is smooth and consistent - not changing RPM at all - only the tach. I'll figure out how to get to the back of the panel and do what you suggest and let you know. I won't be on the boat until the weekend.

This is a great club and I'm looking forward to participating more!

[WetWilly]

Hi MAJIC,

Hopefully this will resolve your issue as it has for other members in the past!

We too are looking forward to your participation as well, the more, the better, as we all learn from each other!

Good luck,
WetWilly

[Z 202]

Not sure about the 252, but on my 202 the back of the instrument panel is easily accessed by flipping up the headrest for the starboard bow seat, assuming of course you have a b/r....