Jeep Won't Run

???

 

It appears from all the pictures the arm on your fuel pump is the correct length and curvature. Leading me to two possible causes. First, possible cam lobe worn down. Second, improper fuel pump installation (This to me seems most probable). You confirmed your replacement pump works as designed by manual actuation. Hang in there, this forum will have you back running around and playing with your jeep soon enough.

 

I am late to the thread but have recently been getting fuel pumps that require an 1/8" spacer to make them work. I tried every part number offered anywhere (Probably $300 into this problem at this point) and none of the new ones work without the spacer. I actually bought the spacer on my current L-head test motor from kaiser willys as there description states that the pump requires a spacer. The quality of the spacer was bad as the holes were too small for the 5/16 bolt to go through and the hole spacing was too narrow. Probably the worst quality part I have ever received from kaiser willys. However, every pump seems to work with the spacer installed.

 

Thanks Daryl. Interesting. I know it was needed for the dual action pumps. Guess with changes over the years in pumps, manufacturers must have settled in on one type and now even the single action pumps require the spacer to work properly.

 

I can make one from1/8" aluminum flatstock easy enough

 

From the description the pump arm already is not making enough contact to work, and a spacer is not going to help with that.

 

Found this video. The fuel pumps install the same on L134 and F134 engines . Hope it helps.

Installation Of The Fuel Pump On A Willys MB L134 Engine - YouTube

 

The spacer is used with some of the long-arm style pumps.
-Donny

 

Here is a good discussion on fuel pumps in general which also touches on the use of the spacers.

https://oldjeepcarbs.com/thread/14/572-single-action-fuel-pump

 

New pump from rock auto/Carter brand is the same as my flaps unit. Arm is 2 3/16" long.

 

This is basically it, right? I don't see how a spacer would help?

 

I don't know what I'm missing here. It's pretty straightforward. How/why would a spacer help?

 

A spacer is NOT required for a single-action pump and will only exacerbate the problem if installed. It is my belief that you have an air leak in the fuel line.

 

Some pumps need spacers, some do not…There is a very good and easy to understand write up on different F134 fuel pumps and spacers on Derek’s CJ3B page: http://cj3b.info/Tech/FuelPump.html

 

I am with Rick, and think you have an air leak. A spacer is NOT going to help.

 

i am not saying you are wrong. you are most likely right. but even with an air leak, shouldn't there be some resistance to installing the fuel pump?
wouldn't the lower part of the diaphragm at least chatter when I crank the engine over? with the fuel pump bolted to the motor, and the the cap part off, that does not move at all when i crank the engine over.

my new gas tank/sending unit and fuel pump arrived last week, should have some time this week to address it all. but im still not understanding why the pump isnt appearing to move at all when the engine is running.

 

It has been lurking in the back of my mind for a while. The light just went on after reading your signature. You are trying to install a single-action pump on an F-head motor. The S/A pump is for the L-head motor. You need a fuel/vacuum pump.