knocking sound?

[chattyrona]

We got the old 57 35hp seahorse started! Yeah! Only thing it has an obvious knocking noise almost similar to valve clicking noise on a car. Any ideas?

 

[F_R]

Re: knocking sound?

Are you familiar with how they should sound? Quite frankly, they are sort of rattley engines, nowhere near as quiet as a car. Heavy knocking and banging sounds are a different story. Have somebody listen to it that is qualified to know how it should sound.

 

[CATransplant]

Re: knocking sound?

We got the old 57 35hp seahorse started! Yeah! Only thing it has an obvious knocking noise almost similar to valve clicking noise on a car. Any ideas?

Could be one of several things, some serious, some not so.

Possibilities:

1. Broken ring on one piston -- serious
2. Bad wrist pin bearings or main bearings -- serious
3. Misaligned coil or magnet under flywheel -- not too serious
4. Something interfering with flywheel -- not serious
5. Disintegrating impeller -- not serious, since you should replace impeller anyhow.
6. Piston slap -- serious

There are other possibilities. Does it make this noise constantly? Does it appear to be coming from the powerhead? Does it only make the noise when in gear, or even in neutral?