os 91fx problem
 

Hey guys my os 91 hasnt been run in about 3 years. upon looking over the engine alot of rust was inside, I used navy jelly i bought at lowes did the job. Its not sucking gas with very little compresion, could it be the piston rings ?

RE: os 91fx problem
 

rust might have eaten some of the piston ring away as well as the liner and a bunch of other stuff. making a sufficient gap to loose compression (piston rings and sleeve), If I where you I would change piston liner (if it had rust) and the piston ring. Also check the carb, SPECIALLY the needle valve assembly which tend to get rusty and give everything a good cleanup. Change anything you see damaged. 3 years without use can be pretty tough on this engines. hope this helps!

You can find the replacement part here:
http://www3.towerhobbies.com/cgi-bin...I=OSMG0591&P=Z

RE: os 91fx problem
 

thanks rzarikian, im ordering new ring for piston

RE: os 91fx problem
 

Ahhhhhhhhhhhhhhhhhhhhhhhh: The price we pay for not doing things right the first time is amazing. What if??? ENJOY

RE: os 91fx problem
 

garygee :

Remember to BREAK-IN your engine after you install the new rings! do it per manual exactly as if it were new. I know its kind of boring but it will give you way better performance once you do it. You can download the manual at osengines.com

RE: os 91fx problem
 

Yup, had that problem before. Most likely your ring.

RE: os 91fx problem
 

thanks guys

RE: os 91fx problem
 

also if rust was in the engine you need to replace the bearings or your new top end will be ruined by the bearings!!!!!