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Honda BF50A

Hi,
Does it seem to be oil fouled or fuel fouled?
Have you tried swapping that plug with one from another cylinder?
 
carruthers.steve@outlook. said:
yes. and i have cleaned carbs twice
I believe it is in the thermal valve.
How can that be tested
Click to expand...
Remove SE valve and inspect the needle for wear or scratches. Pinch the needle valve with thumb and forefinger and GENTLY pull outward, no more than a fraction of an inch, to ensure that you feel the internal spring resistance.

Then, hook a 12 volt battery positive to the brown/white wire and negative to black wire.

The needle valve should begin extending in around 2 to 3 minutes and be fully extended....(1/8" to 3/16")... in 3 to 5 minutes depending on ambient temperature.

CAUTION! The valve gets VERY hot during this test so don't touch with bare skin.

Remove the 12 volts and see that the needle fully retracts as it cools to ambient temperature.

I highly doubt that the SE valve is causing one plug to foul but....who knows?

Have you ever adjusted the valves?

Did you synchronize the carburetors after installing them?
 
You've checked/adjusted the valves?
There's a great pro tech named Ian on this site that recommends a certain valve lash for the BF 50 if I'm not mistaken. He says it will help with a better idle.
I'll see if I can find his post for you.
 
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