Tired Old Man
Posts: 11533
Joined: 2/25/2002
From: Central, CA, USA
Status: offline
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Gas Engine Tuning For Everybody Using the 3MM-53
Open both needles to 1-1/2 to start the tuning process. Use a 22" prop if you have one for the initial stages of the game. Once the engine is running peak the high needle and back off enough to hear a difference. The actual amount is unimportant. Now drop the rpm via the throttle down in the area of 2,500 to 3,500 rpm and peak the low needle. Leave it there and go check the high again at max rpm. Lean it to max and back off a touch. Now cycle the throttle fairly quickly from high to low and back to high a few times. What does it do? Does it stumble when going from low to high? Richen the low needle an amount equal to the width of the screwdriver blade that fits the needle. Everything at this point MUST be done in extremely small increments or you will pass the sweet spot to one side or the other.
It will take a few tries to hit that perfect transition spot, but you should be able to do it after learning how gasser carbs work.
Greg,
I wouldn't monkey with the timing just yet. Try the above first to see if that doesn't take care of it. One thing's for sure and that the max rpm is much too low for the engine. A prop too large will do that every time and make tuning very difficult. You'll be trying for max rpm that doesn't sound or feel right when you obtain it and it will be much lower than what everyone else has obtained. Tuning for max rpm with too large of a prop and at the same time trying to keep the engine rich enough to avoid burning it up is a very difficult way to tune a new engine, and one that's very easy to end up wrong.
< Message edited by Silversurfer -- 4/8/2007 5:40:19 AM >
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If you can''''t fix it with a hammer, you have an electrical problem.
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RE: New 53cc engine now available - 
