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Synthetic 2-stroke oil

W

Wotan

Contributing Member
Hi there,
Some short while ago I posted a thread,that due to constantly only using synthetic 2-stroke oil I have reduced the mix ratio on my ´86 50Hp 4cyl Mercury to 75:1.
It was running perfectly and actually better than ever all through this and the last season.. until this morning..
I was speeding along and had not noticed that the impeller failed upon me!
All I noticed was a loss of power, -the feeling like fouled fuel, water in the carb, similar.. I reduced power, extreme rough running..it took me all of 10 seconds roughly to realize there is no way anywhere anymore.
Looking back all steam through the cowling. The motor stopped itself the same moment I pulled the quick stop.

A very shameful and embarrassing tow back into port, -and on first inspection after the motor cooled down on the trailer.., it appears no damage happened to the block! Compression on all four.
If that is confirmed on proper inspection, -I can truly say the synthetic oil has payed for itself, -and you can safely use it in smoke free mix ratio!:D
 
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Keep a close eye on engine temps after you replace the impeller/pump. Other damage can occur on a extreme overheat, if it seized from heat it got real hot at the crank. The thermostat may have been damaged as well. Good compression would be a good sign, look under the flywheel for tar dripping off the stator. Monitor charging voltages close as well. Test your overheat horn you did not mention any alarm?
 
If it started losing power the pistons had already expanded and started skirts to scuff and seize. Oil no matter the type will prevent damage on a overheat. It still may have good compression but damage has occurred.
 
I have taken the bottom off, and the impeller appears intact!!
Just if you put it on your finger the center metal bit has disintegrated with the rubber..
 
If its a Serria impeller they will pay for any damages that may have occurred....
and you need to go back to at least 60:1
 
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