M38 jeep fuel flooding

[Bob Phillips]

I seem to recall a discussion we had on this forum about a fuel pressure regulator that could be purchased to solve the problem of too much gas passing the needle and seat and flooding out the engine. Could not find it- anybody recall what the product was or details??
My jeep now suffering from this problem and the needle and seat alone not able to control the flow. Pull off the carb and a half inch a gas is collected in the intake manifold.
thanks...BP

[BCA]

Bob, First, have you checked the fuel pressure coming from the fuel pump? 3 to 4 psi should be no problem for a normal check valve to handle if you have an original M38 Carter carburetor. If the pressure is higher then the spring in the fuel pump has been distorted. Maybe your float is defective and has filled with fuel so that it won't float properly. If you have a replacement Solex or off-shore Solex copy then there has been discussion about needing to reduce the pressure a bit.... Brian

[rob love]

Bob: When you pull the top off the carb, look for little tiny grains of rust in the bottom of the floatbowl. If you are seeing those, then they are what are causing the flooding. Back in the day, you would pull up to a light or stop sign, and suddenly the engine would rumble then stall out. The only way to start it again was to turn off the fuel at the tap on the frame, clear the fuel, and then once running again re-open the valve.

The cause is minute particles of rust in the tank making it through the rather coarse fuel filter system. With the top off of the carb, look in the bottom of the float bowl and it will look like tiny red sand. The solution is an inline filter. You have a choice. You can replace the inlet elbow fitting at the carb with a 90° 1/4 m-f pipe elbow, then install the little fuel filter from a mid 80s Ford (same filter was on the M151A2 Jeep). The steel line then has to be reshaped to fit onto the filter. However, those same particles that reach the carb can also unseat the little check valves in the fuel pump. Remove the top off the fuel pump, clean out any debris,and install an inline fuel filter into the rubber line between the frame and the pump. If you have cleaned out the pump as described, then you don't need the one at the carb.

Personally, I have never seen a needle valve have a problem with the pressures unless either the float is buggered or the problems that I have described above.

[Bob Phillips]

Thanks Brian and Rob for the input.
My jeep will backfire , sputter, and not want to crank over ( liquid isnt comnpressable ) will order a new needle and seat and check fuel pressures. Half inch of gas in manifold is a real problem. I have seen pressure regulators listed for sale on a number of jeep sites starting about $50 US. I believe this is a common problem- I have an M38A1 which sat in a storage building for several years and seized up. The problem as it turns out was that too much fuel was being pumped into the engine and washed /diluted the oil in the top end of the vehicle , bottom end was fine- engine oil badly diluted with gas.
Will check all the items you have suggested. thanks BP

[rob love]

Have you opened the top of the carb and checked the float bowl for sediment?