M151A2 sluggish in 2nd and 3rd

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jamboly

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Steel Soldiers Supporter
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Magnolia, TX
I have been trying to the M151A2 I got last October road worthy. I replaced the electronic ignition module with one from an "extra" used distributorthat came with the Mutt. I put a new carburator on it. I have checked the timing. It idles real good and seems to run real good in 1st and 2nd gear, but when I go the 3rd and 4th, it seems to take forever to get it up to 50 to 55 mph. It may be that I am just not used to driving this small of a horsepower vehicle, but it just doesn't feel right. I do know that the accelerator pump in the new carb is not working right, but I didn't think that would relate to this problem. I did read about the effects of different octane fuels, and I am running mid octane. Also, I don't think the clutch is slipping, even though I do have a pretty good oill leak (source still unknown). So, is it just me or is there something I can do. How fast should it go if running right? :cry:
 

poppop

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Brooklet, Ga
They don't have big power house engines but mine gets up there pretty good. It is very cold natured and requires some choke until it is warmed up. If I recall correckly the accelerator pump is a little different on these carbs. It works off of vaacum pressure. Mine starts better if I depress the petal a couple times while I am cranking. If the diaphram has a hole in it, it won't pump when you depress the petal. Anytime you depress the petal to accelerate it should shoot in extra gas. Maybe in the higher gears this lack of fuel is showing up more?????
 

Uglyranger

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Waverly Hall, Georgia
I have two 1967 M151A1 Jeeps. One has an A2 setup. Both require full choke when starting cold. As soon as they start I push the choke in part-way and run that way until the temperature gets to normal, around 190 degrees. When starting a warm engine, the choke is not required.
Try running with the choke out about 1/4 inch.
Both Jeeps will run 60 mph plus.....down hill....with a tail wind. :lol:
 

nattieleather

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Cleveland, OH
The M151 requires the choke to be out about a 1/4 inch even when warm...I don't know why this is,but that is the way everyone I've ever played with has been. It seems weired...but for a 151 it's normal.
 

jamboly

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I don't have any problems starting it. A little choke and a few pumps on the accelerator, and it's running. I'll see how it does in 3rd and 4th will a little choke. Thanks
 

ohiomutt

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ohio
I drove over 90 miles in my M151A2 on Sunday. I have owned every version of the M151 Utility Truck. Most of the Time it's Full Choke to Start.

As you drive the M151 play with the choke in 3rd and 4th gear very slight movements in or out will increase or decrease your engines performance. As your motor warms to normal operating temp. you will need to adjust the choke..again.

My M151 goes 65mph with no issues and plenty of room to go faster.
 

badgerord

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Kansas City, MO
Mutts will normally need the choke to start cold, because they do not have a fuel pump in the carb and when they sit for any amount of time the fuel starts to drain back to the tank.

You need your carb rebuilt by Brooks engine. I have 4 mutts, all have Brooks rebuilds.

I have rebuilt carbs for 3 of my Mutts to GI spec, still sucked, had to run with choke out, had a real flat spot in power curve around 30 mph.

Bought new in the box carb, was sure it would fix it, Nope!

Sent 2 carbs to Brooks and they made the Mutts run like magic!, sent 3 more for rebuild for the other 2 mutts and a spare.

Video from brooks
 
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