fuel delivery issue

[Brett]

Is it possible that you may just not have enough fuel in the tank? If you completely drained the tank, 5 gal is not alot to put back in a 24 gal tank. Always check the simple things first.

Brett

[monkeymissile]

I'd add to make sure your tank is vented-if the cap has the fording switch and is in the incorrect position (closed), vacuum build up in the tank can prevent the fuel from flowing.
Gary

Thanks Gary, no fording switch on mine and I believe the tank is venting properly. How would I check?

[m37jarhead]

Bruce:
From a $$ standpoint you're probably in luck because the 12V fuel pumps are plentyful and are generally cheaper than
the 24V versions. Check the prospective pump you want to buy for pressure. It should be in the 4psi to 6psi range and
operate on demand.
The wiring is not in your harness unless previously installed by another owner. Buy an on/off switch, run the wiring
to the pump and there you have it. Place the pump as close to the fuel tank as possible. A good in line fuel filter before
the elec. pump is also a very good idea.

New fuel lines may be in your future. If you want to save a buck, first flush the lines with carb cleaner or similar.
Used pressurized air. Repeat until clean. Use in line filters after cleaning. Check for future contamination. Then decide if you
need new fuel lines. Old fuel lines will continually produce rust particals but they can easily be handled by filters. If the
collection of "crud" continues to be unacceptable, consider new lines.

As suggested check the vent on the cap too. Vapor lock is also common on M37's. Your only choices are to check every
possible fuel issue from the tank to the carb. until you find what seems to be the problem.

Also do a "search" on this site for anything related to fuel. There are volumes of discussions on fuel pumps, filters,
lines, etc.
JB

[Tuko]

heres a link to a 24V fuel pump I bought for a good price, so far so good!

http://www.ebay.com/itm/NEW-CASE-ELECTR ... e4&vxp=mtr

[ZGjethro]

Buy an on/off switch, run the wiring
to the pump and there you have it. Place the pump as close to the fuel tank as possible. A good in line fuel filter before
the elec. pump is also a very good idea.

This is how I wired my 24v pump to get things rolling. I always intended to run the circuit thru an oil pressure sending unit, so when I run into a tree and get knocked out, at least the pump is not still spewing gas from broken lines into my hot engine bay. It has been three years now and I still have not rewired my "temporary" fuel pump switch.

[Tuko]

i tapped mine right off the wire running to the ignition coil. the ignition on/off switch takes care of the juice flow to the fuel pump. If I hit a tree im screwed too.

[ZGjethro]

Tuko, I might wire mine that way. Currently, I operate my M37 by the rule of three everytime I turn it on or off. I turn on 1) the battery disconnect. 2) the ignition. 3) the fuel pump.

I have a separate circuit for the ignition and the pump, but I am sure they would both work off of the same fuse.

[Cal_Gary]

Hey MM, should be a small vent tube connected to the fuel tank pickup on top, not as large as the fuel line, and routed forward toward the carb and intake. Check this image from the VPW catalog, items L to AA to D to C:

http://www.vintagepowerwagons.com/pdf/parts/03fuel.pdf

One way to tell if the vent line is plugged is if you take the fuel cap off after running it and a big gush of air rushes into the tank. Mine was eaten up, disconnected, and somebody had a plug in place of the vent tube.
Hope this helps,
Gary

[monkeymissile]

Hey MM, should be a small vent tube connected to the fuel tank pickup on top, not as large as the fuel line, and routed forward toward the carb and intake. Check this image from the VPW catalog, items L to AA to D to C:

http://www.vintagepowerwagons.com/pdf/parts/03fuel.pdf

One way to tell if the vent line is plugged is if you take the fuel cap off after running it and a big gush of air rushes into the tank. Mine was eaten up, disconnected, and somebody had a plug in place of the vent tube.
Hope this helps,
Gary

thanks again Gary, I will check. I do recall not hearing anything when I took off the filler cap during my initial investigations, but it's never a bad idea to check again. After I got it running again, I noticed the fuel level was slowly dropping in the fuel filter so I still have an issue somewhere!

[m-37Bruce]

Bruce:
From a $$ standpoint you're probably in luck because the 12V fuel pumps are plentyful and are generally cheaper than
the 24V versions. Check the prospective pump you want to buy for pressure. It should be in the 4psi to 6psi range and
operate on demand.
The wiring is not in your harness unless previously installed by another owner. Buy an on/off switch, run the wiring
to the pump and there you have it. Place the pump as close to the fuel tank as possible. A good in line fuel filter before
the elec. pump is also a very good idea.

New fuel lines may be in your future. If you want to save a buck, first flush the lines with carb cleaner or similar.
Used pressurized air. Repeat until clean. Use in line filters after cleaning. Check for future contamination. Then decide if you
need new fuel lines. Old fuel lines will continually produce rust particals but they can easily be handled by filters. If the
collection of "crud" continues to be unacceptable, consider new lines.

As suggested check the vent on the cap too. Vapor lock is also common on M37's. Your only choices are to check every
possible fuel issue from the tank to the carb. until you find what seems to be the problem.

Also do a "search" on this site for anything related to fuel. There are volumes of discussions on fuel pumps, filters,
lines, etc.
JB

Re-conditioned tank, mostly new lines, pressure cleaned and all new fittings, re-built Zenith carb, now the pump and a relay switch. Did I mention that I plumbed the old pump to itself?
Thanks for Heppin JB,