S.T. 51 Runs ok for 30 seconds
04-20-2009, 12:07 PM
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S.T. 51 Runs ok for 30 seconds
My ST51 has been mounted on two different planes with the same results. Running 15 nitro and 18 oil, and have tried # 3, #5,#8 plugs with same outcome. Engine starts and idles ok, I advance to full throttle and motor rapidly advances,,after about 20 to 30 seconds of doing this things change. Next time I advance the throttle the motor takes 20 seconds to accellerate. Sounds like it is laboring to rev up. Once at full throttle it will stay running. If I reduce to idle it will stay running. If I advance the throttle again quickly it will die, no sputtering, just falls off. I removed the carb and started at the beginning (so I think) on adjusting. Mid range , then high then low all with same outcome. I really like ST motors and know I am just overlooking something. I have tried two seperate fuel delivery assemblies, same result. Motor has acted like this since new out of the box from the hobby shop. I bought it last year and lost interest and now find I need to use it. All carb passages are clean and not restricted, leaving the glow stick on does not cure the problem. I am thinking of pulling the head just to investigate. Just to mention again first 30 seconds everything sounds great then it starts taking 30 seconds just to rev up. Prop size I failed to mention is 11x6. After motor dies the prop still turns freely.no bearing seizing up. Any thoughts?????????
