Post by sisumilitaria on Sept 6, 2017 18:11:47 GMT -5
The old carb on my 43 MB was leaking and grubby so I decided to go the easy route and just buy a rebuilt unit. I got the carb from Midwest Military in Minnesota. I installed the carb and it seems to run very rich. You never need to use the choke as it starts right up cold. If I even touch the gas pedal before hitting the key, it's flooded. Like I said, never have to use the choke. Runs fine once it's going but smells very rich. I thought maybe the float level was high but checked it out and it's actually lower than spec at 1/2" instead of 3/8". The engine ran fine before and the old slobbering leaking carb never ran rich like this. Mixture screw is 1 3/4" turns out. I'm thinking the metering rod or throttle pump might be set to the wrong specs but wanted to ask the experts here before I start playing with it. Thanks!
Post by Scoutpilot on Sept 6, 2017 19:14:55 GMT -5
Can you give me some numbers? Vacuum gauge reading? Dwell and idle RPM? Fuel pressure and flow rate? Part number, gap setting and condition of spark plugs? Condition of the distributer?We’ll start there.
Last Edit: Sept 6, 2017 19:16:40 GMT -5 by Scoutpilot
Post by sisumilitaria on Oct 14, 2017 21:45:08 GMT -5
Sorry for taking awhile to get back here. Jeep is on the farm quite a ways away but went there today. Plugs are Champion J8C gapped at .030 Vacuum gauge reading is a steady 21 inches at idle. When I hit the throttle it drops but comes right back up to 21. Fuel pressure gauge only goes to six psi but fuel pressure pins the needle there. I'm thinking this could be the problem. This pump has been on the Jeep for at least 15-20 years and I never had this rich running problem until recently when I changed the carb. Could the fuel pump be defective? It seems to pump very strongly. Would it be better to use a pressure regulator? Don't know the flow rate. Rpm is about 600 rpm. I don't have a dwell meter. Distributor in good shape. Good bushings, new plugs wires points condenser cap and rotor. The pump on the jeep is a newer style without the glass bowl that I got from napa many years ago. I have a new one on the shelf with glass bowl that I got from Walck's to use on another Jeep. Should I use this pump to replace the one that is currently on this jeep?
Post by sisumilitaria on Oct 15, 2017 9:53:35 GMT -5
Yes, the carb is a Carter WO. Everything I've read says that fuel pump pressure should never exceed 4 1/2 lbs. and this one pins my gauge at 6 lbs + at idle. Could this high fuel pump pressure be floating the needle and making the carb run rich?
Post by sisumilitaria on Oct 18, 2017 22:13:36 GMT -5
Not sure what you mean about being a clone. I bought the pump from NAPA about 20 years ago and never had a problem with running rich until recently. This pump does not have a glass bowl like the original pumps. Will try a regulator and see if it makes a difference.
First. Please post a couple of photos of the carb. I’m curious because you describe a starting sequence very much like a Solex's. Second. Since the mid to late fifties, most fuel pumps, including AC were built with valves that were pressed in, instead of being placed and secured. They look like the original on the outside, hence the name “Clone”. Other than replacing the diaphragm, there is little that can be done to rebuild it and additional failure risk is in the valves.