Put the boat in the water (Whaler 170 Montauk 2004 with Merc 90 4-stroke - carbs) and it appears the tach is reading high - I know the feel of the engine and performance and it can't be right. AT idle (750 rpm) it reads 1500, at cruise (about 4000 rpm) it reads 5500. If you push it past cruise it pins the dial over 6000. The engine recently had some maintenance, but the dealer does not recall looking at the tach. So I don't know if it happened then or during Winter storage.
It is not erratic but very consistent and repeatable. My feeling is it must be the gauge, since the tach pickups I know about on outboards are very simple affairs that detect the magneto poles as they fly by. I cannot conceive of a pickup or engine problem that would cause this behavior. But I am not that familiar with newer Merc outboards.
Anyone else have an idea?
It is not erratic but very consistent and repeatable. My feeling is it must be the gauge, since the tach pickups I know about on outboards are very simple affairs that detect the magneto poles as they fly by. I cannot conceive of a pickup or engine problem that would cause this behavior. But I am not that familiar with newer Merc outboards.
Anyone else have an idea?
