Hi all, first time posting here, hoping for some opinions and ideas. 98 Fatboy, 29000 miles, never an ounce of trouble. Yesterday took her out on her first ride of spring , eased into it with about 50 miles. Stopped and fueled up to head home, she started sputtering after about 2 miles, eventually stalled. Pulled both plug wires, had good spark. Pulled air cleaner off, noticed a weak and intermittent spray from the carb rolling on the throttle. Pulled the fuel line off, no fuel. Left fuel line off and cranked her over, no fuel from the line. Pulled petcock face off, no clog in the tank screen. Was ready to order a manual petcock and block the line, decided to pull the vacuum hose from my S&S carb, pulled some vacuum on it with the fuel line disconnected, today I have fuel. But she is periodically missing now. Seems reasonable that my petcock diaphragm is taking a dump, but why am I pushing it home yesterday, but it starts today? Thanks in advance!

 

Maybe your filters breaking down and clogging the petcock?

 

reminds me of a walbro carb when the fuel pump section diaphragm gets hard from alcohol fuel and quits pumping.
i gutted mine a long time ago. i run high speed and can not afford a lean out when the manifold signal is lost at wot.

 

well, that was mu first thought. Pulled the face of the petcock and the valve out of the petcock body and it flowed through the tank screen like. Faucet. Am wondering if that diaphragm could have vapor locked or just been stuck in the seat. Also noticed it pops a bit, I think even though it was running yesterday again, that it is starved for gas.

 

Think I’m just gonna pull that OEM vacuum petcock out and go manual, plug the vacuum line. I only use non alcohol fuel, but it had 20k mi on it when I bought it, the previous owner may have used cheap gas, will see once I dissect that bad boy I guess. My bigger concern was that I was maybe missing some other reason why it would have been blocking fuel to the carb. But other than the fuel valve which Is fine, that diaphragm seems to be the only other link in the chain between the petcock and my carb.

 

You have 2 options..
1) get a Pingel and never look back..
2) pull the valve out of the petcock and make a gasket and plate so it will always run..
just make sure you turnoff your fuel when not in use....