tenacious101010

My Feedback: (97)

I purchased a used G-38 Zenoah here on RCU. This is my first gas engine. How do I tune it? What are the starting high and low needle valve settings? Any inputs on tuning would be a great help.
Thanks

jcflysrc

My Feedback: (50)

I think the low needle setting is about 1 and 1/8 turns out, and the high is around 1 and 5/8 out. This should get you close I think.

tenacious101010

My Feedback: (97)

Thanks JC, Will the pinch test work on this motor like we use for the glow engines?

karolh

I suggest that you start with both needles set at 2 turns out, start the engine and allow it to warm up for a few seconds then tune the high end for max rpm.

Then lean the low end until the engine shuts down when you go from idle to WOT. Richen the low end in very small amounts until the engine transitions smoothly from low to high. Retune the high end for max rpm and reduce by 2-300 rpm, and you should be good to go.

The pinch method is not as effective on gas engines as it is on glow, as gassers take a much longer time to react to the pinch.

Karol

arobatx

I tune like Karolh does....works!

Chad