Fuel Pump Help???

[MIKE2A6X2]

First of all i want to start out by saying im new to the site. I recently purchased a 51 m37. The engine will run if i squirt gas in the carb so i know the whole AIR/FUEL/SPARK is good. I have the big military style pump without the sight glass. The problem i am having is basically knowing what each line on the pump does. The previous owner put a brand new pump on it but from my experience just because its new doesnt mean it works. Im sure you all know there are 4 fittings on the pump. Because my tank has a hole in it, I ran a hose from my gas can into the inlet (bottom left) of the pump. I then cranked the engine and the fuel came out of the outlet (bottom right???)
I blew air through all the line to make sure there was no blockage.

What i dont understand about that is the bottom right fitting has a steel line going up to the intake manifold. Which caused a half gallon of gas to disappear?? Before i keep explaining everything, does anyone have any input so far???? Please help

 

[vtdeucedriver]

Take a pic of your fuel pump!!! It sounds like your fuel tank is attached to the vacuume side of the pump. Your pump is in two sections, if your looking at your pump and I am assuming that its a Standard M-37 fuel pump. The inlet from the tank should be the upper right fitting (looking from right fender) and your outlet will be the upper aft fitting that goes directly to the carb.

Take some pics
Welcome to the world of M-37s and join us over at the www.g741.org

 

[Oilleaker1]

Double acting pump. Top is gas, bottom is vacuum. Should have the cast label "in" by the hole in the bottom and top sides of the pump. Gas from tank goes to "in" on top, The "in" on the bottom should be connected to the wiper hose, the out of the bottom goes to the intake manifold. The out on top goes to the carb. If the bottom is full of oil, there are seals on the pump shaft that are bad and it needs rebuilding. Same goes if you find gas leaking out, bad diaphram then. To check for spark, you should get the waterproof adaptor if you still have that type system. The carb has a vacuum operated accelerator pump, so you can't just pump it with the linkage. To put in points, condensor, or coil, you can remove the lower fender panel for access over the tire. Patience is the key. A manual is a must for working on these. Lots of answers for you here or over at Willysmjeeps.com. John

 

[MIKE2A6X2]

Sorry it took so long to get back. Well, today i finally got a chance to work on this thing. I had ordered a different style fuel pump. Its just a single IN/OUT with a fuel bowl. After getting some adaptors and bleeding the air it fired right up. I felt like i hit the lottery when i heard that thing run. Thanks for the help guys

 

[MIKE2A6X2]

Heres my next issue. The pump that was on it seems like it was brand new. It looks as if you pulled it out of the box and bolted it on. I took it apart to check the diaphrams because todays gas eats away at those things. I couldnt find anything but i did lose about a half a gallon of gas into my oil. (oil was changed before installing new pump). Are there hard to rebiuld? I want to be able to use my wipers in the future.

 

[Baron3-6]

Check this out:

Matt Gieselman | M37 Fuel pump rebuild