Lorne@pro-rc.ca
50cc
Jetpainter;4251 wrote: Nebwake, I just checked the needles on my GP61. The low is at 2 1/4 and the high is 1 1/4. That's a long way off from stock, but it runs good there.
That sounds a little lean on the top.
I have tuned a bunch of customer engines and most are lean on the top. (When warm the rpm will drop further and motor will run hotter)
Make sure it is a little fat on the top by getting it 200 rpm rich and then lean back 150 rpm. Remember to compare a warm engine to a warm engine.
The only problem with the GP61 and 123 is they get hotter when lean but don't fall off rpm too much