Dies When Cold
I have an older Wisconsin engine with a Stromberg Carburetor that powers a 1500 watt generator.
I recently purchased a carburetor kit from Mikes Carburetors, which I had installed by someone I know who is very good with Carburetors. Even though he did not replace the float, he said it was in good condition. I believe the Carburetor is a model #L45A2 or #425041. The kit recently installed is #K6139.
The engine did not want to stay running when you first start it, and still does not stay running after putting in the new carburetor kit. It has a small street elbow coming out of the bottom of it, which is stuffed with what looks like steel wool, that gets wet and drips gas when you first start it. It is obvious when you first start it, that it is running rich, as there is a lot of black smoke coming out of the exhaust.
I have been able get it warmed up enough at times to get it to idle by starting several times, and adjusting the carburetor several times. If I can get it to that point, the generator works well, running an electric 4” hand grinder at normal speed.
I would like to know a proper setting for the lower valve, which I believe is the main jet. I understand from the instructions I got with the carburetor kit, that the fuel mixture jet, gets richer as you turn it inward, and leaner as you turn it outward. I would like to know your recommended setting for that jet also in starting. I would like to also know what the proper setting is for the float.
Having put new points in the magneto, it starts reasonably easy, under normal conditions when cold. My problem is in getting it to idle when it is cold.
However, the carburetor which runs richer when you turn any adjustment clockwise is rare — most run leaner. I suspect that this may be at least part of the problem.
General rule for “baseline” adjustment of an updraft of that era:
High-speed mixture (lower adjustment): 2 counter-clockwise turns out from bottomed.
Idle mixture( upper adjustment): 1.5 counter-clockwise turns out from bottomed.
From those adjustments, you work inward (clockwise, engine warm) to obtain the correct adjustment.
Is the gas fresh? Or does it smell sicky-sweet?
Has the ethanol separated from the gasoline? If so, ethanol is heavier than the remaining gas and it goes to the bottom of the tank where the pick-up is — engines won’t run on pure ethanol.
Is the choke valve opening completely?
Is the float/needle/seat system completely shutting off the gas flow from the tank? He may have to remove the carb, turn it upside down and suck on the fuel inlet to see if any air passes through it (it shouldn’t).
Could the fuel pump (if so equipped) be over-pressurizing the carb? (pump on an engine such as that would deliver about 2-3 lbs. max).
Is the float “gas-logged”? (sloshes when you shake it).