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Engine basics => Engine set up tips => Topic started by: frank mccune on July 07, 2016, 08:16:36 AM
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Hello All:
While flying the above engine I notice that it does not run in a nice 4 cycle mode. There is no problem with running this engine in a wet 2 cycle mode. I was wondering if this engine is not designed to run in a 4 cycle mode. In the four cycle mode, it runs very rough but when leaned out a bit it runs in a very smooth 2 cycle.
This is not a flying problem but just a question about the HP Gold Cup .40 engine. This Gold Cup is a joy and pleasure to use.
Comments?
Tia,
Frank McCune
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Hello All:
While flying the above engine I notice that it does not run in a nice 4 cycle mode. There is no problem with running this engine in a wet 2 cycle mode. I was wondering if this engine is not designed to run in a 4 cycle mode. In the four cycle mode, it runs very rough but when leaned out a bit it runs in a very smooth 2 cycle.
The stock engine was certainly not intended to run in a 4-stroke. I suspect it would run smoothly in a 4-stroke at a much higher RPM than you would normally use for 4-2 stunt purposes, but I haven't even seen a Gold Cup run since the very early 80's.
Brett
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Hi Brett:
I think that you got it correct! This engine loves to operate in a wet 2 cycle. So, why insist that it operate where it is not happy? Lol.
I would like to use 11" props but the grass is a bit high for that where I fly. Perhaps a good 3 bladed prop would be the answer. An 11-4 or an 11-5 prop appears to be a good choice for this engine.
Be well,
Frank