Home › Forum › Ask A Member › 1966 20hp Wont Start/Backfire › Re: 1966 20hp Wont Start/Backfire
OK, you had the carb apart and you removed the high speed jet, all is clean.
The motor won’t run unless you prime the cylinders with fuel, then only for a few seconds.
Fuel runs from the carb when you remove the bowl drain plug and pump the fuel line, correct?
How about the carb throttle linkage, perhaps the butterfly is stuck open somewhat. I’m pretty sure the choke linkage on that engine holds the butterfly open a bit to help start a cold engine. So, if the butterfly is stuck, or the choke linkage is messed up, this might explain the no start. The engine starts when primed, but then cuts out/spits/backfires because the throttle linkage is stuck open somewhat.
I’m assuming no major work was done to the engine (other than the carb) since the engine was last run many years ago, no one has messed around with the intake manifold have they?
You might try opening up the low speed needle another turn just to help get it started and keep running, then you can dial it in once the engine will keep running for you.