88' Mercruiser 165 harmonic sound

[cyclops222]

I listened again. Why so much valve / lifter noise ? Check all the rocker arms for correct action adjustment. Way too noisy if hydraulic.

 

[nola mike]

I listened again. Why so much valve / lifter noise ? Check all the rocker arms for correct action adjustment. Way too noisy if hydraulic.

No rocker adjustment on that engine

 

[cyclops222]

That engine sounds and vibrates like valve hydraulics or rocker arms need checking out.

 

[tank1949]

Here is an old trick to determine if you have a bad plug. Get you some rubber gloves and pull each distributor plug wire at distributor while examining tack. You sure timing is correct? It may be advanced too much and causing pinging. Just an idea...

 

[cyclops222]

That or the distributor cap and or rotor arm has invisible carbon tracks in it causing misfiring's on 1 or more cylinders. P

 

[Cal-b]

Perhaps pull the dizzy and turn the pump with a drill and long hex rod, see if it duplicates the noise. I used that method to prime my rebuilt 3.7 before firing up

Thanks for the idea! I finally found some time to do this today. See link below. Unfortunately I don't have the means to pull the engine right now, I guess I'll need to let the boat sit for awhile. At least now I know where the sound is coming from.

 

[tank1949]

Thanks for the idea! I finally found some time to do this today. See link below. Unfortunately I don't have the means to pull the engine right now, I guess I'll need to let the boat sit for awhile. At least now I know where the sound is coming from.

My distributor oil pump primer has a sort of bearing it top coming out of dist. I didn't see one on yours. The bearing centers rod and keeps it there.