I'm at a loss for figuring this one out. Friend of mine brought his trike to me, said the bike starts running rough after a few minutes ride, stalls out. Asked me to clean out his gas tank, lots of rust visible through the filler cap. I do it, clean out the petcock, lots of debris in the top & when removing the gas line, it's got a continuous flow of gas which made me think the diaphragm is stuck in the open position. I take it apart, clean up the rubber bits & put back together. No longer flows gas. Put gas in the tank, takes a couple of cycles to get gas flowing & it starts up but won't rev to upper range. I drain the bowl, take the bowl off the carb thinking the main is plugged. It wasn't. No tears in the piston diaphragm. Spray everything down with carb cleaner, put everything back together. Finally, it runs. Get about 5 minutes down the road, roll off the throttle & motor stops running. It fires up instantly but won't idle. I adjust the idle adjuster & it runs. Go for another spin. Acts like it's running out of gas, dies but starts right back up, runs good for a minute or so & dies. This is where I get stumped. When I pull the filter cover off, this is what I see...melted plastic. What in the world is going on with this?
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