M151 maint help???

Ok all, here is todays issue.

The m151 idles nice but stumbles on acceleration. It gets a little better with the choke out about 1/2. I figured that it might be on the lean side so I tried turning it up and it got just worse. Now i know I have a exhaust leak at the manifold so the carb is comming off.....................think it needs a rebuild???

I wish I kept my MV magazines, I know there was a article about this not long ago.

mutt

I had that problem on my Mutt and i relpaced the fuel filter and rebuilt the carb. and that fixed it.

RE: mutt

Ditto on the fuel filter. It happened to me before with a NOS fuel filter...

RE: mutt

Now would this be the in tank filter??? There is a inline filter installed on the jeep.

RE: mutt

I will change it but I doubt...........it has a NOS tank

RE: mutt

The hesitation sounds like the accelerator pump. If I remember correctly it has a diaphram and works off engine vaccum when you accelerat. If it has a hole in it then its not pumping. Also you do know that all Mutts have to have the choke pulled out to some degree. The military mechanics whould pull it out till it ran good, then lossen the lock screw on the cable and push the choke knob back in all the way to the dash. This set the choke in the proper position and the non mechanically inclined soilders could drive them.

RE: mutt

Yeah, I can pull it out a bit and it gets better. I will throw a couple of things at it to Freshen it up, then I wont need to worry about it when I am away from home.

RE: mutt

a bit is more like 1/2

check for vacuum leaks or cracked intake manifold

Check the accelerator pump, and your ignition timing.

Yes the 151 is meant to run with the chock pulled out about a fingers width. The studder can be many things, carb, fuel filter, manifold, exhust leak, timing, valve adjustment to name a few.

To get a quick time on it loosen the bolt on the bottom of the distibutor and turn it so that the little box on the end of it with the one wire coming out touches your first and second finger that are together touching the oil filter. Then lock it back down. This will give you a good timing close to dead on...till you can hook a light up to it. Then replace the in line fuel filter and clean the carb sometimes a good cleaning is all the carb needs. If it keeps up look into adjusting the valves.

I've owned a M151 for 20 years now so I hope I know a thing or two about them....

There is not a filiter in the fuel tank there is how ever a screen(sock) in there allso cleaning the fuel lines out will help. I owned a m151a2 four about 5 years and I had all those problems. I never ran mine with any choke about a year before I sold it it ran great with out choking the carb

I can empathize with you. We have a M151A1 that had the intank pump and filter. We also started to experience this cutting out. Near the same time, we put the MUTT on the lawn and decorated it for Christmas with lights. Some kids came up on the lawn when we weren't home and turned the ignition switch on.

Ours had been converted to a Swiss system, which is electronic ignition.

We spent months on forums and lots of money on parts.

We replaced everything ignition wise and it seemed better and then went right back to the same thing.

We got a cheap 12v electric fuel pump and mounted it on the firewall. My son wired it to work with the 24v system by going to the battery, but don't ask me to explain that one. Anyhow, we pulled the pump and filter out of the tank and couldn't believe the crud on it! It looked like what you see divers coming up with from ship wrecks. Since then we haven't had any problem except our light switch quit right after the electric fuel pump was installed and my son just installed a new one today and all is well.

So, the in the fuel pumps can be a problem with the filter or pump. And ignition can do that as well. Do you know what kind of ignition system you have?

Beth

Hi beth,
It has the stock ignition system.

Today I could not sleep so I puttered on it. I pulled the plugs and they looked pretty good. When bonnie got home I had her bump the starter for me and I put my thumb over the whole. Pretty even compression so I am happy there. At some point I will borrow a gauge (mine is in vt) and see what the numbers are.

I did find a busted bolt that was missing that holds the exhaust manifold to the head. This weekends project will be to pull the carb and both manifolds and change the gaskets and remove that broken bolt.