Fuel Pump on A/C 620 (update)

[renxgil]

OK JP, Got the fuel pump, installed it and got her running, but I'm having a problem. At a low idle she runs fine, at full speed it will run fine and then start sputuring, clear itself resume running fine, and continue this pattern of peformance. Anyone have a clue as to whats going on? Thanks for your help in advance.......REN

[JP]

Good! Well sorta, Is the timing dead-on? New (or not too old) points, same w/plugs. Breather's clean & the balls too? Sorry don't remember if these were talked about. Is all the old fuel pump accounted for (seems I do remember something about parts & magnets). JP

[powermax_paul]

Ren, Is it possible you have some water in the gas? I get that once in a while and if I'm on an incline the water rolls down to the intake side of the tank and causes some sputtering.

[renxgil]

Ok Guys, Thanks again. Paul, think I'll try some dry gas, and see what the reasults are. JP, how is the timing set on these engines? Thanks again.............RENXGIL

[JP]

Point gap @ .20 & align timing w/timing light 'dead on' the pto marks. If you don't have the timimg tab or think its's bent, the timing marks are on the flywheel (tough to see) & you usually have to move the flywheel to to check the tab where the pto clutch is (which means if you're doing this, the motor is out....) JP

[gretsch]

Could be the carb main jet is set a little too rich or lean. Try seeing if it helps to choke it just a little. If that helps, it is set to lean. If it gets worse, then it is set to rich. It is also possible to have a vacuum leak where it meets at the manifold (use some aviation gasket sealer on both sides of the gasket and it that won't be a problem. Possibly the air filter rubber hose is mounted loose (less noticeable effect but can happen).