help found small hole in top of lower piston

[mike lewis8]

please help i have a 1980 15 horse johnson , i was changing plugs and found a small hole on top of lower piston , i am not sure it is completly all the way thru and less than one quarter inch round the model is a j15rcsd plugs looked fine and gas is correct what is the problem i am having and is it a big problem , willing to pay for info or to fix this motor

 

[CATransplant]

Re: help found small hole in top of lower piston

You're gonna have to pull the head on that engine and do a thorough inspection. That's no big deal. What you find when you do that is going to tell you what you'll need to do.<br /><br />Holed pistons are always a problem, and you have to figure out how and why that hole got there before putting the repaired motor back in service.<br /><br />If you want to know if the hole is all the way through, though, run a compression test. Holed piston equals zero compression.

 

[CATransplant]

Re: help found small hole in top of lower piston

OK, I see you've already posted this question on the forum before. Please stick to your original post. That saves everyone time and you get all the answers in the same place.<br /><br />One problem: One question.

 

[mike lewis8]

Re: help found small hole in top of lower piston

ok what things should i be looking for as i pull off the head and also any comments on how this may have happened , sorry about posting the question twice i am new to this

 

[mike lewis8]

Re: help found small hole in top of lower piston

i just took a compression test and both cylinders are at 95 pounds is that an ok pressure or ??

 

[Solittle]

Re: help found small hole in top of lower piston

95 lbs is just fine for that engine. If it is running OK I wouldn't worry about it. If you had a hole the compression would be a fat 0.

 

[stratus5]

Re: help found small hole in top of lower piston

Originally posted by realtree:<br /> please help i have a 1980 15 horse johnson , i was changing plugs and found a small hole on top of lower piston , i am not sure it is completly all the way thru and less than one quarter inch round the model is a j15rcsd plugs looked fine and gas is correct what is the problem i am having and is it a big problem , willing to pay for info or to fix this motor

The piston is holed from the cylinder running too lean. Probably a plugged up carb.<br />Clean the carb after you replace the piston.