So my single-dual progressive weber ran well until my first gas fill up after purchasing the car. After fill up it ran really rough, no power (1-3 gears), and sounded like a cylinder was missing, plus now backfiring. Drove home 1/8 mile from the gas station (under 30mph) and now won’t start. Turns over, engine cavitates, spits (from the muffler), bangs from the exhaust and does not start. The speedster drove flawless until the fill up. I’ve put 260 mile on it since purchase and first fill up. Before my first fill up were short stints of driving around town/highway with no issues. I would open up to 4,500 rpm here and there but nothing sustained.
I did a lot of research and searching on this site, with a few owners with similar issues.
I checked and noticed that my #4 spark plug wire was off (not sure how) and was sure that was the cause (from forum advice). Reconnected, didn’t change, still banging and not starting. The carb squirts gas on throttle. Checked plugs (black), replaced with new gapped .006. Checked valves, some of the exhausts were a bit tight, reset all to spec .006. Still no start (starter turns fine). I have a brand new optima battery as well. Coil is electric flame thrower installed 2012 (PO) receipts.
So, now I’m figuring the “bad gas” theory I’ve read about on this site. Replaced engine filter and filter before electric pump. Found a ton of crap (pics) before the fuel pump in the filter. Not sure if any had gotten through. So replacing that filter now shows clean gas (in the filter).
I also purchased a carter rotary to replace the electric pulsing pump/w kill switch, thinking the pump has particles in it as well (it’s very loud). Planning to install.
Now I’m looking to take apart the weber and find/clean what I can (first time) and see if that solves my problem. Also, going to run a compression test.
I’m a missing anything and how difficult is to service the single carb myself (cleaning)?