Ford M151A2 sputter.

1959 - 1978, M151, M151A1, M151A2, Technical questions and discussions, regarding anything related to the M151.
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mike2u
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Ford M151A2 sputter.

Post by mike2u » Sat Sep 09, 2017 7:51 pm

Im going to start by saying, I know this has been asked many times but if I don't figure it out I do not know if I will live to see my other trucks restored :shock:

Ok, to the good stuff. My M151A2 ran great for a few years, but sometime after being put aside for a while, it started running rough. I did a complete carb rebuild but it has never been right since. So it sat for a few years. Now, she fires right up but it has this intermittent sputter, almost sounds like a miss. It sounds very similar to my Dodge WC trucks when they flood out. Last year I put all new plugs in. I am at a loss of what is going on here. The oddest part is, last year when I turned the fuel to the engine off, the Ford runs perfect for a second or to before she sucks the remaining gas dry. I have not tried this since I went back through the carb.

I am not an expert on these newer style military trucks, but I would love to get her running for my dad. Any help would be greatly appreciated.


Rickf
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Re: Ford M151A2 sputter.

Post by Rickf » Sun Sep 10, 2017 6:36 am

These carburetors are very picky when it comes to cleaning and it sounds like you may have some garbage in the idle circuit, probably from sitting from the sounds of it. You have to take the carb off the truck and blow out the idle passages with carb cleaner and air. In the throat of the carb under the idle mixture screw you will see a series of holes, these are the idle mixture passages. I usually back the idle mixture screw out almost all the way and then spray carb cleaner into these holes and blow them out with air. This is best done with the carb apart. If you take the carb apart then the little tube in the bowl center that will fall out is the idle jet and shoule also be cleaned out. Be very careful not to lose the very small gasket on the tube.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

mike2u
G-First Sergeant
G-First Sergeant
Posts: 149
Joined: Thu Jun 24, 2010 6:34 am
Location:

Re: Ford M151A2 sputter.

Post by mike2u » Sun Sep 10, 2017 7:06 am

I have had the carb apart before, and I am not sure the idle jet went back into the bowl with the gasket. Is it an O-ring that slides on the idle jet? I cant picture what it looks like.

Rickf
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Joined: Sun Mar 19, 2006 10:04 am
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Re: Ford M151A2 sputter.

Post by Rickf » Sun Sep 10, 2017 7:51 am

It is a gasket that slides on the jet. I have used very small O-rings in the past when the gaskets were missing. I actually have a carb of my own that is missing the gasket and it runs fine but I do not condone that since you never know what the problem is if something crops up. I rebuild these carbs so I know that one is missing the gasket and if it has an issue I will add one. The problem with using an O-ring is getting the jet out the next time you need to. There is nothing to get hold of without damaging it. It has to be a very small O-ring.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

mike2u
G-First Sergeant
G-First Sergeant
Posts: 149
Joined: Thu Jun 24, 2010 6:34 am
Location:

Re: Ford M151A2 sputter.

Post by mike2u » Sun Sep 10, 2017 4:07 pm

Today I pulled the carb back off.Cleaned it well and thoroughly. I am missing that O ring. Regardless, I put everything back together and she will run down the road fine. I can cruise around 50mph with ease, but she still has the same sputter, and really runs better with the choke pulled out a quarter inch.

Rickf
G-Lieutenant General
G-Lieutenant General
Posts: 5911
Joined: Sun Mar 19, 2006 10:04 am
Location: Pemberton, New Jersey

Re: Ford M151A2 sputter.

Post by Rickf » Sun Sep 10, 2017 4:39 pm

Have you adjusted the idle mixture screw at all? I always adjust for best idle then go just a hair to the rich side and that eliminates the need for the choke. That is the cure for the need for choke while driving, choke at idle is something else, That is a idle mixture issue.

How is the rest of the engine tune up? Valve adjustment and timing are critical on these engines. Float setting in the carb is also critical. For a military engine these are very picky in that all of the settings have to be right on the money for them to run good.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone


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