Old chainsaw engine
 

Hi

Got my engine to run just fine but in the wrong direction, notice after reading the instruction that I had put the sencing pin 35 degrees before TDC not after like the instruction said. Fixing that problem the engine backfire every time and almost crussed my three fingers that I used to flip the prop. Now when I check this again I noticed that I have almost 20 degrees of slack in the TDC area. My question is shall I add my 35 degrees after those 20 degrees or what?

RE: Old chainsaw engine
 

Most gassers run the best at about 28 degrees BEFORE top dead center...You can find TDC by putting something in the spark plug hole to keep the piston from going all the way to the top...Turn the crank clockwise and mark the hub and case at that point..Now rotate the crank the other way and make another mark...TDC is exactly halfway between the two marks...

RE: Old chainsaw engine
 

Now my ignition system wants to have it 35 degrees after TDC if I want it to turn the right direction (ignition system made in 1989). But like you said in the middle of that area.

RE: Old chainsaw engine
 

For an engine to run correctly the spark must occur about 28 degrees before top dead center in the direction you want it to run....An engine timed at 35 degrees after top dead center will not run at all, the spark will occur when the piston is on the way down..Never happen....

RE: Old chainsaw engine
 

The sense pin shall be 35 degrees after TDC because of the latency in the electronics. It's a very old Runtronic system that I got from a friend but it may exist new system that what to have it like you describe.
I had it 35 degrees before TDC and then it started everytime but clockwise instead of counterclockwise. The problem I have is that I wanted to know how to handle to slack in the TDC area.

Like you said I shall start the degrees from the middle area in TDC.

RE: Old chainsaw engine
 

I have a old chainsaw engine and want to convert it, how do I go about doing so???

RE: Old chainsaw engine
 

Good luck on the range check!!!! I have an old McCulloch chain saw engine on my 1.20 size stick, no matter what I do, massive interferance from engine to servos....Trust me, I have tried everything. If you have no problem with yours, please let me know!!! Good luck!

RE: Old chainsaw engine
 

b717doc....

Yours is an unusual problem, as there are lots of us flying these things with no problems. Check my other post on your thread for a few ideas.

Take care,
AV8TOR