i ran a 1 1/2 tanks of fuel through this new motor with a 11/6 prop. i noticed some fuel coming out of the top head screw and the joint between the muffler halfs so i tightened up all the screws on the motor. is this normal ? also is this enough breakin so i can fly it now ? i'm also using %15 nitro mix with %18 oil and one tank full throttle and half tank variable throttle.
doug,
If the engine will hold a wide open slightly rich throttle without sagging, you should be good to go...
The loose screw problem you had is common, and is caused by the soft screws stretching slightly... Get rid of them in favor of harder socket head machine screws.. DuBro has them in their car parts line... The screws OS uses for mufflers, and the JIS head screws used for the heads on the newer engines are junk; not fit to be on a decent engine... Like every major change OS has recently made, it seems to be a cost-cutting, rather that a quality measure...
Cheers,
Hey Bill........ your comments make me think you might be able to answer this question - what type of threads did OS use in the early
1970's???? The major diameter for my OS 60 Goldhead head screws is identical to a 6-32, but there are more TPI than 32. I'd sure like to replace those &*#%$ philips head screws.David
The closest Metric thread to a 6-32 (.1372") is a 3.5mm (3.485mm). The thread pitch is .6mm, roughly about 42 tpi.
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