12 HP Gale Buccaneer knocking

[restornator]

Okay i am not sure what to do. I started it up after making a new head gasket. It only has 70psi compression on both cylinders. It starts, then i hear a knocking noise, strong enough to stall the engine. I got it to rev up in forward and run for about 30 seconds, but the knocking noise was still there. I know it's not seizing up because it cranks over right after it stalls. Crankshaft, connecting rod, worn out flywheel key, my homemade head gasket? I really want to keep this motor, but i not if it has major damage.

Any ideas?

 

[1946Zephyr]

Re: 12 HP Gale Buccaneer knocking

One thing I heard to do if you have a loose connecting rod, is to take both plugs out and turn the motor, till both pistons are at the center point in the cylinders. Insert the dowl in both cylinders while you're turning the flywheel and make sure both pistons are moving in and out. Then turn the flywheel back just a tiny bit (so not to reverse your waterpump vanes) then stick a small dowl in the spark plug hole and see if you could push the piston at all. If you feel the dowl push the piston in a slight bit, then it's very likely that your connecting rod cap has come loose.

 

[restornator]

Re: 12 HP Gale Buccaneer knocking

One thing I heard to do if you have a loose connecting rod, is to take both plugs out and turn the motor, till both pistons are at the center point in the cylinders. Insert the dowl in both cylinders while you're turning the flywheel and make sure both pistons are moving in and out. Then turn the flywheel back just a tiny bit (so not to reverse your waterpump vanes) then stick a small dowl in the spark plug hole and see if you could push the piston at all. If you feel the dowl push the piston in a slight bit, then it's very likely that your connecting rod cap has come loose.

thanks, i'll try. So i put pressure on the dowl while turning the motor? i know they both move in and out, when i had the cylinder head off, i could visually see it.

 

[bktheking]

Re: 12 HP Gale Buccaneer knocking

You sure its the engine and not the rewind starter?

 

[F_R]

Re: 12 HP Gale Buccaneer knocking

If I may take a bit of liberty with what Zephyr said, stick the dowel in the plug hole and just touch and follow the piston as it goes up, then about half way down. Don't push--just follow. When the piston is about half way down, stop turning. Then give a push on the dowel. If you get a clunk, somethng is loose. Same thing he said, but "my" procedure, your choice

Do you want to know the weakness of the 12hp? They have a lousy lower crankshaft seal. Water gets into the crankcase and destroys the connecting rod. You usually figure it out when the rod comes sticking through the side of the crankcase.

But don't jump to conclusions. Could be a loose flywheel or something. But DON'T run it any more till you locate the trouble. You don't want to see that rod sticking out.

And replace that seal whether it needs it or not.

 

[1946Zephyr]

Re: 12 HP Gale Buccaneer knocking

Yea, I talked with a guy today who picked up an old 35 Johnson and it was making noise. All he was able to find was a loose flywheel nut.

One other thing you might check, is make sure everything on the armeture plate is good and secured. I've heard of coils and stuff under the flywheel coming loose and making people think that a rod was going out.