Thunder Tiger 91 4-stroke issue?
#1
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Join Date: Mar 2002
Location: westfield, NJ
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Thunder Tiger 91 4-stroke issue?
After 8 years I got my 91-4 stroke going again but it appears to be leaving fine powdered aluminum in the exhaust oil residue. Is my cylinder degrading or the piston, or the bearings? I am running 10% nitro with added castor oil. Any help is appreciated.
#2
Your best bet is to disassemble the engine and make sure all the parts are moving freely and not rusted or gummed up with castor oil.
#3
I’m going to guess something in the exhaust is loose. A lot of times there is a battle in the muffler that is swagged or riveted in place a s vibration causes the aluminum to wear and shed the particles suspended in the exhaust oil.
#5
#7
Life will be grand if only this one line answer will solve all the engine's ill. No black oil does not have to mean the engine is too lean. There are way too many variables involved. One of the main reasons for black oil means that a muffler is loose and the aluminum is rubbing against aluminum with some oil mixture added. That can happen when the engine is either lean or rich.
#9
OTOH, getting back to the OP regarding the shiny aluminum powder that is most likely a loose muffler since that is the closest aluminum part to the exhaust outlet. Or that could be from something outside of the engine. It is hard to tell without adequate information from the OP.