Just got a carb back from being rebuilt. Quality was great, not knocking the rebuilder...i think something got out of wack during shipping...... im at 11 initial w/ 31 total for timing. 1 3/4 turns out on adjustment screws. Idles great and has GREAT throttle response and get up and go...unless......... After she warms up and you get down the road it jerks, spits and sputters at light throttle low speeds/rpms. If you lay into it, it clears up and is fine. If i leave it in second and keep the RPMs up around town its a dream. Even at idle in gear it wants to jerk/lurch forward. Rebuilder said he set the float to 10/32 or 11/32. I am getting gas seeping out of the upper front gasket neat the accelerator pump shaft...but not out of and around the pump shaft its self...just seepage from the front of the gasket..... Am i running to lean at 1 3/4 turns out still? I am going to try to turn it back out to 2 1/4. I'm thinking float set to high?? Something else?
Sounds like it is flooding to me. The float level may be too high. Could be a defective float or needle/seat. The idle mixture screws have nothing to do with it.
Did he put a new float in it? If you're seeing seepage, the float could be "heavy", if it's a composition one. This has the same characteristic as being set too high. Do you see black smoke coming out the exhaust? This indicates a rich condition. If you are not seeing it, your float is probably OK. HOWEVER, looking at the original complaint, I'd say it's the accelerator pump/circuit. The choke, partially closed, can cover up a lean condition caused by a weak pump shot.
I'm thinking the float or needle & seat may be one thing, but the part-throttle issue sounds like a sticky power piston. Devon
When engine is warming up, the choke is on and enriches the fuel mixture. When the engine warms up the choke is no longer in play and the additional enrichment is also not there. It may be too lean at cruise speeds, it may be as simple as replacing the primary metering rods with a richer rod. If you have (for example) 45B rods, try swapping them out for 43B rods and see if this makes it better.
