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1951 M37
Oliver in Georgia

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Re: engine dies after 3 min

Discuss fixes, upgrades and modifications to your M37

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Re: engine dies after 3 min

Postby RMS » Thu Dec 07, 2017 4:04 pm

markkish79 wrote:if I used the etw1 parts kit on the CDN model carb, it would cause some issues and or not work ?


im not saying that your problem is due to the etw1 kit being used on the canadian carb. but that it will always run on the lean side due to the smaller jets.

I still believe your problem is somewhere in the idle circuit. I know you have two filters so the chance of something bypassing the filter is slim. .....but it only takes the smallest bit of crud ( bit of rubber shaved off the fuel line during instillation?) to block up the low speed jet. specially when said jet is smaller than stock. requiring it to work harder by delivering more fuel at the same vaccume pressure at the throttle plate. the idle bleed hole can also get plugged up by contaminants entering the air cleaner elbow but unlikely.

pull the top off the carb once she dies if the bowl is full your fuel delivery is fine. if you see any bit of crud or fuzz the idle circuit could be plugged remove low speed jet (clean and inspect) and blow comp air through the idle adjustment screw hole ( inspect and clean screw) cover top of carb with clean cloth when blowing to see if any contaminants come out. do not blow down through the carb as that could lodge crud deeper into the circuit.

your low vaccume signal could be due to the mixture (carb) or timing witch should be no more than 6 deg btdc. all my long head flattys pull 18 to 22 @ idle.
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Re: engine dies after 3 min

Postby markkish79 » Sat Dec 09, 2017 3:39 pm

Ok I actually gained some ground today, lucky for me its been snowy and freezing. So its not the carb, but all great Intel from all of you thank you for your experience and expertise. I ran a jerry can straight to the carb like suggested earlier and she ran for 20 min straight. So its either that new 24v elec pump acting up and cutting out. The pressure switch I ran the fuel pump to so she runs only when oil is moving in the engine, or some sort of vapor lock happening from the old gas cap, or the fuel pick up. Idk if the fuel pick up would have anything to do with it. I know the vent line that goes to the engine is a little stripped and I put some fuel silicon around it. I just didn't think it was a big deal plus this started happening before I messed with the pick up. Would the fuel cap cause it to rev up and die? Could it be that stupid?
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Re: engine dies after 3 min

Postby rickf » Sat Dec 09, 2017 5:14 pm

Like I said three times now, Put a vacuum line in the suction side line and see if you are drawing a vacuum. You keep asking the questions and we keep giving the procedures to check it but we cannot tell you the answers without doing the tests.
1953 M37
1964 M151A1
1967 M416
1984 M1008
4/1952 M100
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Re: engine dies after 3 min

Postby jim lee » Sat Dec 09, 2017 9:56 pm

C'mon, To be fair he did the jerry can test. And now he has 1/2 the issues to worry about. His engine & carb are fine.

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Re: engine dies after 3 min

Postby rickf » Sun Dec 10, 2017 7:38 am

OK, But some instrument testing is going to HAVE to be done to find the problem. It is either that or start throwing parts at it until you find the right part. That can get real expensive real fast. And being a master mechanic that is quite contradictory to my way of thinking. Sorry for the rant, it just bothers me when advice is given and ignored. And then asked for again for the same issue.
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1964 M151A1
1967 M416
1984 M1008
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Re: engine dies after 3 min

Postby jim lee » Sun Jan 14, 2018 12:06 am

So I'm dyin' to know, how did the story end? Was the fuel system plugged up? Did the pump actually fail? Did they get married in the end?

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Re: engine dies after 3 min

Postby vargaspj » Thu Jan 18, 2018 12:04 pm

You don't have the gas cap screwed all the way down do you? It's supposed to be loose unless fording. If it's screwed down tight it creates a vacuum in the line.
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Re: engine dies after 3 min

Postby rickf » Thu Jan 18, 2018 4:07 pm

Say what?!! That is why there is a fording valve in the cap. I have never heard of leaving a cap loose. You would have gas spilling all over the place.
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1967 M416
1984 M1008
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Re: engine dies after 3 min

Postby RMS » Thu Jan 18, 2018 4:13 pm

wish I could afford to fill her up that far :lol:
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Re: engine dies after 3 min

Postby rickf » Thu Jan 18, 2018 4:24 pm

Wouldn't have to go much above half a tank to have it splashing against the cap. My motor home gets 6 MPG, I judge everything else I have off of that and it all sounds good then. :lol: :lol: :lol:
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1984 M1008
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Re: engine dies after 3 min

Postby just me » Thu Jan 18, 2018 4:54 pm

The tank on an M37 vents through the carb airhorn elbow. The correct cap does not have a vent and is supposed to be kept screwed down tight. Otherwise, dirt and water will get in the tank.
There is a fitting on the top of the tank connected to a line from the tank to the front of the truck. From the side rail, it goes to the engine hardline through a rubber hose about 7" long.
If someone hasn't 'field modified' your truck, there shouldn't be a vent issue.
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Re: engine dies after 3 min

Postby jim lee » Thu Jan 18, 2018 9:43 pm

My ventes all around the inspection plate that the fuel level sender goes through. A total pain in the B&^%!.

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Re: engine dies after 3 min

Postby NAM VET » Fri Jan 19, 2018 6:25 am

I made up all new hard lines, here is a pic of the top of the tank, showing the sending unit, and the vent connection and the as-yet-unattached fuel line. I made them up with copper/nickel lines from FedHill. The chap there told me he could not get quality hard line connectors, so to reuse my old ones, which I did. He did have new USA made fittings for the flared end connections. By the way, it was going to be difficult to precisely bend and cut the two hard lines from the tank and master cylinder coming forward to attach to the two flex lines coming from under the alternator (mine is the big 100 amp thing), so had my local shop make up two longer flex lines, then I made up FedHill hard line extensions and when my motor was back in the truck, trimmed them and put a short piece of rubber hose connecting them with fuel injection clamps to the hard lines coming forward to my tank and master. Here is a pic showing in the center the two new lines before trimming them when mounted. It was easy to remove my truck's bed, using an engine hoist, the only thing that took a little time was removing the rear shackles to get to the back nuts. Will post the pic of the tank next.

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Re: engine dies after 3 min

Postby NAM VET » Fri Jan 19, 2018 6:26 am

and here.....

[url][url=https://postimg.org/image/lhg3tif11/]Image[/url][/url]
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Re: engine dies after 3 min

Postby just me » Fri Jan 19, 2018 6:28 am

jim lee wrote:My ventes all around the inspection plate that the fuel level sender goes through. A total pain in the B&^%!.

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McMaster sells sealing washers that slow that down some! Same as used on Harley FI tank covers.
https://www.mcmaster.com/#94154a300/=1b71471
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