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1986 Classic 50

B

Bpos

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After priming, Walbro carbs run good on fast idle, only to die after a few seconds. No low idle and I have to reprime the bubble in order to crank. Carbs are adjusted at 1 and1/2 turns. I've tried less but not more. How do you know if air might be getting sucked in to the system? No leaks. Plastic tank about 10 years old with new fuel line. Thanks.
 
I have rebuilt both carbs complete. Am I correct in saying that the fuel pump is built onto the carb where fuel enters the carb?
 
It's got me frustrated. That's for sure. New fuel lines from tank to carbs. Old plastic tank. Wondering if there's a vacuum somewhere affecting the idle. I've read where the primer bulb should be pointing upward. Carbs fill up, motor tachs on up but only for a few seconds and then it dies and I have to reprime it. Sure it's simple but may have to take to an expert. Thanks for your help.
 
The primer bulb has an arrow pointing to the engine side. It is a lot easier to prime if the primer bulb is in a vertical position . Is it possible you got the fuel pump gaskets backwards? Or the spring and the plastic part that pushes the diaphragm in wrong? When you prime the carbs do you see any fuel leaking? Possible the float is not set properly? Low speed jet may be plugged? Go over your carbs again .
 
No leaks. Didn't realize the fuel pump gaskets could be installed wrong. They seem to fit only one way. Is there some video of placing these gaskets in the right order? All I can find are black and white parts list. Not much help. I did notice the pick up tube in the tank inserts loosely into the pick up cap assembly. In fact the first pick up tube fell off and lies at the bottom of the tank. Maybe that doesn't matter. I'm grateful for all your help.
 
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