Low compression cilynder due to damaged piston??

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Eddyhifi

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Sep 2, 2012
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Hi everyone ,i removed the damaged piston and i attached pictures. Why those rings stuck like that in the piston ???
How can i prevent it does not happen again in the future? Yamaha 130hp 1998 carburetor 2 stroke.Thank's
 

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Capt Ken

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Re: Low compression cilynder due to damaged piston??

That cylinder leaned out and over heated. Cause of the lean condition will have to be solved when the engine is rebuilt or it will happen again. Usually it's due to a dirty carb.
 
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Eddyhifi

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Re: Low compression cilynder due to damaged piston??

Thank's a lot for your help.I have been running this engine for about 4 years without cleaning carb. I opened the one that work with the damaged piston and was dirty. I bought the original gasket and was almost $30. Do you think is better buying the whole kit and replace all the parts? or, just cleaning the old ones and replace the gasket?
 
RogersJetboat454

RogersJetboat454

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Re: Low compression cilynder due to damaged piston??

Eddyhifi said:
Thank's a lot for your help.I have been running this engine for about 4 years without cleaning carb. I opened the one that work with the damaged piston and was dirty. I bought the original gasket and was almost $30. Do you think is better buying the whole kit and replace all the parts? or, just cleaning the old ones and replace the gasket?
Click to expand...

Get a kit. You should be doing all the carbs, as well as making sure your fuel supply system is in good nick. You have a fuel filter too, right?

With a piston that looks that bad, what does the cylinder it lived in look like? Post pictures.
 
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Eddyhifi

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Sep 2, 2012
Messages
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Re: Low compression cilynder due to damaged piston??

The cylinder has some visible marks but you can not feel it when you touch it. I clean it up but some marks made by piston are there.Do you think is ok just replacing this for new piston and 1207122349.jpgrings or the overhaul is the only solution.Thank,s in advance
 
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Capt Ken

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Re: Low compression cilynder due to damaged piston??

You are going to have to have each cylinder honed at the very least. Then measured at the top, center and bottom. You will probably find the cylinder bigger in the middle. If there is, you will need to bore the cylinders. I can tell there is a ring groove at the top from the picture.
 
gm280

gm280

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14,605
Re: Low compression cilynder due to damaged piston??

That bore really doesn't look good. Take it to a quality machine shop and have them evaluate it. IF it does have to be bored, and it looks like it will, make sure you do all bores and not just the one bad. Otherwise you will have a serious problem on your hands in the long run. Bore, new pistons and rings will fix this for sure. But do have the connecting rods and bearings checked as well. May as well check everything at this stage and turn out a trouble free engine in the long run... A little extra money now will save a lot of money later on...
 
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boobie

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20,826
Re: Low compression cilynder due to damaged piston??

You don't have to bore all the cyl's if they and the pistons are okay. A new set of rings on them will do. Save some meat in them if you have probs in the future.
 
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