Carb Sensitivity to Crud

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m75
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Carb Sensitivity to Crud

Unread post by m75 » February 19th, 2020, 12:34 pm

Well, the A2 started running poorly, almost starving for fuel, then stopped running altogether. Strong batteries, good fuel pressure, etc.

Time to remove the carb and see what happened. After the second time checking, I noticed that the tip of the idle tube appeared to be sealed. Used very fine brass wire, brake cleaner spray and compressed air, blowing the matter out of all orifices I could find.

Wrapped it all back up, cranked (with switch off) to bring fuel back to the carb, hit the ignition switch, cranked again and started right up.

Working backwards from the carb, I found that the in-line filter was clogging as well. Cleaned the filter, added a Fram in-line visible filter as a back-up, and will have to consider draining the fuel tank for a serious look-see for contamination. The tank was repaired two years ago (pin holes) but not sealed such as with a POR-15-type product. I think this is where the next emphasis is going.

It's all a learning game, right?
Jim Peterson
SGM, 31B Retired 2015
1961 M151 -Sold
1974 M151A2, Working It!

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rickf
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Re: Carb Sensitivity to Crud

Unread post by rickf » February 19th, 2020, 2:07 pm

Having that inline filter on there is a good insurance policy, if you use the clear plastic ones you can see what is in there and they are cheap, keep a couple in your spares box. I gutted my original filter out so it looks like it is there just for looks but it is nothing but a hollow shell. The NOS ones did not do much for fine particles as you have found out. And that idle mixture setup is very sensitive to that stuff. Next time you can save yourself some time and effort by taking the idle mixture screw out and blowing some carb cleaner down there followed by a shot of air. Not a big blast of shop air but enough to blow out and crap all the way back to the bowl. Then run the idle mixture screw in GENTLY to the seat and back it out two turns and start it up and let it run for a little bit to get all the carb cleaner out and then reset your mixture. Note, it will be flooded when you go to start it so it will take a little more cranking than usual.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Fil Bonica
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Re: Carb Sensitivity to Crud

Unread post by Fil Bonica » February 19th, 2020, 3:26 pm

I usually change both filters annually .
Depending on mileage it may be more often.

Years ago had the A2 with the same problem.
Several attempts at doing just that did not fix things. In frustration pulled the tank.
On inspection it was found to be contaminated with fine , white crud. Cleaned it out thoroughly with hot water, detergent, then lacquer thinner.Dried tank and reinstalled.
8 years later it us still fine .
Now change filters annually.
K1ABW

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m75
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Re: Carb Sensitivity to Crud

Unread post by m75 » February 19th, 2020, 6:43 pm

Any recommendations as to some type of sealer for inside the fuel tank after cleaning?
Jim Peterson
SGM, 31B Retired 2015
1961 M151 -Sold
1974 M151A2, Working It!

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Re: Carb Sensitivity to Crud

Unread post by rickf » February 19th, 2020, 9:02 pm

I would also be interested in the "latest and greatest" in tank sealers. That white stuff is in all of my military tanks, it has to be something that they coat them with at the factory.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

Fil Bonica
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Re: Carb Sensitivity to Crud

Unread post by Fil Bonica » February 20th, 2020, 2:51 pm

Always thought that the white residue was a byproduct of the gas itself.
First jeep I got had it through the whole tank.
It always seemed to get worse when it dried.
Once clean it appears to stay gone.
As far as a coating goes I would just keep an eye on the tank and keep it clean.
Failing that I would use POR or such.

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Re: Carb Sensitivity to Crud

Unread post by rickf » February 20th, 2020, 3:06 pm

I have never seen that coating in any of the many civilian tanks I have dropped. Only the military ones. If they were galvanized I would understand it but they aren't.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone

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