1953 Johnson JW10 intermittent knock

[sneuri]

"Hello all,

Last fall, I pu

"Hello all,

Last fall, I purchased a 1953 Johnson Seahorse JW-10. I've rebuilt the carb and installed new plugs and an impeller. I've got the motor running but it began knocking badly last year just before I put it away for the winter. I've riched up the oil/fuel mixture right around 30:1 (I had tried using pro mix that can supposedly be used for any ratio) but I've gone back to a straight two-cycle mix at about 30:1. I had originally suspected a broken piston ring. But, occassionally, it'll smooth right out and run with only a little click every now and then, even up to mid-throttle (above "start"). Then without any warning it'll start knocking again. I've run about 2 tankfulls of gas through it now. When it's knocking ,it sounds like there are marbles rattling around inside."

 

[guest]

"Doesn't sound very good.

"Doesn't sound very good. Oil mix should be 20-25:1 if memory serves.
If it has a rewind assy try removing it then check if the noise is still there.(use E-rope to start) If the noise is still there a remove the flywheel and check for loose mag plate. Other than that I'd say an internal inspection is needed before something real bad happens like a rod hanging out the side of the engine. Really, it sounds like a bearing failure, either from normal ware over the years or from incorrect oil / mix.
Hope you get lucky."