ETW1 carb issues (M37 NOS unit)

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wc56daveyboy
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ETW1 carb issues (M37 NOS unit)

Post by wc56daveyboy » Fri Oct 09, 2015 5:03 am

I recently went thru my entire fuel system on my M37. relined gas tank, brand new drop in stainless steel filter in the tank, all brand new armoured lines up to the NOS fuel pump and NOS carb. you cant do much better that that! :wink:

anyway, as this truck is at a remote location, and I dont get to it often, its weeks between when I can run it.

Last time I was there, I was making adjustments to timing, etc...I noticed the carb was running poorly.

WT?

I took it for a ride, and coming to a stop, the truck just died.. would not idle.. fast idle, its fine...under load, acceleration, just fine.

I tried adjusting it.. the idle mix screw, completly out or completly in, did little to nothing...

I got to thinking, using past memory, having this issue before, ended up that the carb had sediment, or crap in it. requiring a cleaning

now how could this be? its all new.. I did run the old carb for a spell on the truck after the lines were put in, just for the reason that IF I left a small spec of something in the lines, it would flush out before I put my nice brand new expensive carb on!

anyway.. the entrie system.. its all new. I bought a NOS fuel pump and NOS carb from VPW.. at the time of purchase, I voiced my concern over the NOS units over a more modern rebuilt unit as I read about the interanl diaframs and such may or may not be compatiplabe with todays fuels.


they said that the NOS carb, even though built in the 80's are fine with todays fuels, and that I should NOT be seeing any gasket failures due to the fuels.. they think, however, that the gaskets could shrink, and cause vacuum leaks.. and that my first thing to do should be to tighen all screws around the carb and see it that fixes it.

I will try that first.. but...I think I may pull it apart as well and clean out what offices I can with a can of carb cleaner.

anyone have any similiar experiences? anyone have a general guildline for me to start?


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Re: ETW1 carb issues (M37 NOS unit)

Post by motto » Fri Oct 09, 2015 9:56 am

It surely sounds like contamination of some kind causing a blockage in the idle circuit. It doesn't take much.
I would also be a little wary of installing a NOS fuel pump although my pumps go back to WW2 and what you have is more recent. I once severely damaged a Chev engine with a NOS pump in which the diaphragm had become porous allowing fuel to fill the sump (oilpan).
It just occurred to me.
Another possibility is a vacuum leak, you haven't broken or damaged a wiper supply line have you? Perhaps a rubber connector or line perished somewhere?

David

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Re: ETW1 carb issues (M37 NOS unit)

Post by wc56daveyboy » Mon Oct 12, 2015 10:10 am

thanks for the reply

well, had an hour or two to fiddle with the truck on Sunday before getting back on the road for home.

Started at the carb.. tightened all screws. nothing was loose...

So I took it off the truck, and opened it up for the first time it was assembled at the factory.

yep.. as expected. full of sediment.. not fine rusty stuff as I had seen in the past, coming from rusty tank and fuel lines, but more of a yellowish in color fine silt of sorts. :?

not sure what this is.. is the inner diaframn on a fuel pump this color?

anyway, I did clean the carb thoroughly and put back on the truck.

I didnt fire it up, because I didnt want the same thing to happen. (i.e. fill with the same sediment)

It will need to wait until I return with a modified fuel line from the fuel pump to the carb, containing an clear in line filter, so I can see if more of the sediment comes from the fuel pump or further down the line.

my guess is the fuel pump beign the culprit, seeing as I have a 100% cleaned tank, in tank stainless filter, and brand new fuel lines from the tank to the pump.

I already talked to Steve at Vintage about this, and as expected, he will honor any return on it, if its either carb or the pump. he did offer some assistance on the trouble spot to look for, like tightening the carb screws (they were tight) as well as other places to look.

will see once I get her running again with an additional fuel filter just before the carb

thanks!

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Re: ETW1 carb issues (M37 NOS unit)

Post by softskin_driver » Wed Oct 14, 2015 11:39 pm

What did you line the tank with? Is the yellow contaminate metal or yellow dissolved non metal particles? Check the inlet needle valve and seat...brass material here, also look at the accelerator pump seal. The only other yellow stuff would be an old filter or the stuff you coated the tank with. Run it with a lawn more tank or other temporary tank. Does the problem go away? I have seen silicone sealer, Teflon tape and tank coatings all in different trucks cause similar issues. Knew a guy that had silicone in his fuel tank roaming around it would out of the blue cause vapor lock symptoms and non starts. You could jump up and down in the bed and fix the issue temporarily by sloshing the fuel around.
Another friend for some reason used teflon tape on every fitting when replacing the fuel lines. And I had a cheap needle and seat disintegrate and cause me all sorts of stalling and flooding issues. Check one thing at a time starting with the tank and eliminate them and move on. you'll find the issue. Good luck
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Re: ETW1 carb issues (M37 NOS unit)

Post by wc56daveyboy » Thu Oct 15, 2015 4:51 am

thanks for the reply.

Well, I coated the tank with a sealer system I have been using for years with fantastic results. in fact, I have a local supplier right near by.

http://www.kbs-coatings.com/

I have used it now on three military vehicles tanks as well as both of my crawlers gas tanks and have had no issues. I know the tank is not the issue here as I have been inside the tank when I installed the fule sender unit, months after the coating was applied and gas sitting in the tank.

Besides, its silver in colr, the liner material I mean.. so thats not the culprit... thanks for the pointer in that direction though!

I also did NOT use any thread sealer or teflon tape on any of the flare filltings or pipe joints to the system, ruling that out.

I am wondering, however of two issues:

1) the inside of the carb, as it sat for so many years, NOS or not, I beleive the the base material, being a aluminum? or other non ferous material, has a residue, or white rust as its sometimes called, on the inner surface, breakign down now that fuel is sitting in there. thats one possibility.

2) or the fuel pump diaframn is breakign down wit the modern day fuel.

either way, both units are NOS and from the same supplier, sold as such, so once I determine which unit it is, Ill return it.

For now, the carb has been cleaned thouroughly awiting my return NEXT weekend to put on an additional see -thru filter just ahead of the carb to eliminate any additional residue coming in.

If its somewhere donw the line before the carb, Ill know as more will accumulate in the new filter.

If its the carb, disinegrating inside the bolw, that too will be evident.

in any case, your right.. Ill get to the bottom of it!
thanks again for posting and for potential leads to where to look! always helpful.

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Re: ETW1 carb issues (M37 NOS unit)

Post by Marty, SoCal » Thu Oct 15, 2015 4:29 pm

There is a large brass screw on the top center of the float bowl. It is actually an emulsion tube which bleeds air and fuel for the idle circuit. If you remove it and blow the tiny orifices out with carb spray and/or compressed air, then reinstall it, it may clear up the idle problem. (It usually did on my friend's Dodge WC)

I recommend and often install a larger than stock fuel filter made for fuel injected vehicles on any old car with a suspected contamination issue. The element in an EFI type filter traps smaller particles (10 micron) compared to the original filter or the typical carb type filter. They also will not bypass if plugged. The metal case will never leak and will hold pressures well over what a carb system runs at.

The one I use for 5/16" (8mm) lines is one made for a 1977 Datsun/Nissan 280Z (Fairlady Z in Europe and Japan). Readily available at most local parts stores. Wix part number 33022 or equivalent. It has push on nipples for use with regular hose, no special fittings needed. On my friend's Dodge WC56, I installed it in the rubber hose between the frame and fuel pump and it cured it's dirt problem.
http://www.oreillyauto.com/site/c/detai ... &ppt=C0023
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Hope this helps!
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Re: ETW1 carb issues (M37 NOS unit)

Post by cooler king » Thu Oct 15, 2015 6:26 pm

My old case backhoe with gas engine, kept plugging the fuel filter, due to rust in the tank. I needed the backhoe now.
I happened to have a remote oil filter in my junk. I had second thoughts about using an oil filter ( screw on type) for gas.Thought it might disintigrate or melt or some thing.Gave it a shot anyway. That was 8 years ago works great. I Unscrew, screw on a new every couple of years.

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Re: ETW1 carb issues (M37 NOS unit)

Post by wc56daveyboy » Fri Oct 16, 2015 6:14 am

thanks to both you gentleman for your suggestions!

Cooler King: great idea, but I dont think I got that kind of room for a spin on remote oil filter unless I route it far and away.. good out of the box thinking though. Love it!

Marty: yea, I bought an el-cheapo see thru plastic job, in line filter.. I like this WIX better, so if the clear one does the trick, ill buy this one for a more permanent solution.

I hate having had bought all NOS stuff only to having to resort to this "band-aide". something I would have done for a rusty, un-attended to system, when I replaced EVERYTHING to avoid this to begin with!

Geez. well, maybe Ill find the true culprit to my woes and fix it.. it takes time.

thanks all for your suggestions and time to respond..

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Re: ETW1 carb issues (M37 NOS unit)

Post by Keyslammer » Fri Jan 19, 2018 11:47 pm

I just rebuilt my ETW1 carb on my 1953 M37. I had a bad float valve and decided to go thru it. After reassembly, I used a marine priming bulb to fill the carb and bench test it. I discovered that my carb is leaking fuel between the top and bottom halves. All the fasteners are tight and the carb body is not cracked. Is there a BETTER gasket then the rigid Grey one found in the rebuild kits?? Is there a reasonable sealant that can be used?

Thanks for any advice!

Keyslammer


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