okelly

I have an older 91 Surpass I engine; I started using it after being stored for a while. I adjusted the valve clearance as per instructions and ran the engine on homebrew 20/20 (4/1 synth/cast).After adjusting both NVs, the engine was spinning an APC 15x4W @ almost 10k and idling was @ 1.85k. So far, excellent. Transition was snappy on the way up but on the way down, just before it idles I get a backfire.
BAX you're my last hope, I have no idea.....

Thanks

Bax

My Feedback: (11)

If the engine's running well, and the only problem is a backfire when you rapidly close the throttle, then you have nothing to worry about. It's common on a lot of engines. We'd suggest that you're trying to idle too slowly, but if the engine works well with such a low idle, great!