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Starting problem on OS 70

Old 09-19-2006, 07:17 PM
  #1  
vetter63
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Default Starting problem on OS 70

I have an older FS70 4-stroke that has been run only about 10 times and it ran well, mounted upside down on 10% nitro fuel. I just moved the engine to a different plane mounted rightside up running 15% cool power and it positively won't start, or even fire. I've checked the glo plug out of the engine and it looks OK. Have also tried a different plug. It too, checked out outside the engine. Fuel seems to reaching carb during cranking. I even tried hand priming the carb and still it won't fire. I've taken the carb apart to assure no dirt or obstructions. Thinking something was wrong with the in-plane set up, I've set the engine up on a test stand with the same results. All start attempts have been with an electric starter. I've taken valve cover off and and valve movement seems normal. Help!
Old 09-20-2006, 09:27 AM
  #2  
Bax
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Default RE: Starting problem on OS 70

If an engine has good compression, a good plug, and is getting fuel, it should fire. The only reason it won't would be if one of those three are lacking.

When we choke the engine, we have the glow plug battery OFF the plug, open the throttle to full, and cover the intake with a finger or the choke valve (if there is one present). We crank the engine forwards until we hear fuel starting to 'spit' out the exhaust port. We then close the throttle to about 1/4, add the glow plug connector and spin the engine. If we're hand-propping it, we'll go backwards through compression. It will usually then fire and kick forwards, running.

If the engine won't fire at all, then one of the three is lacking. It has bad compression, the plug's bad or not lighting enough, or the fuel needs to be replaced (or just gotten to the cylinder). You'll need to do some detective work to see.....or you could send the engine to us for inspection/service.

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