Fuel Problem?

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
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phil.c
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Fuel Problem?

Post by phil.c » Mon Apr 10, 2017 7:40 am

Tried to fire up jeep this week but no joy. Put fuel down air intake and it started fine, it then runs and ticks over as it should.
Tried it again today and same thing. Carb is a Carter, a bit confused as once it's going it has no issues but seems like I,m getting no fuel from the carb on initial startup.
Phil


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Re: Fuel Problem?

Post by Joe Gopan » Mon Apr 10, 2017 8:40 am

Disconnect the fitting at the carburetor, before and after priming you should get a healthy squirt of fuel when you turn it over (with ignition off). Here's a simple test for volume of the fuel pump.
Turn down the carburetor line fitting and with the tank connected, pump out a couple of strokes to be sure the pump is primed. Using a half-pint bottle or similar measure, pump 1/2 pint of fuel by cranking the engine with the starter motor. Count the strokes necessary to fill the measure. If more than 20 strokes are required, the fuel pump is insufficient, the tank line is leaking air, or the fuel supply is restricted.
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phil.c
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Re: Fuel Problem?

Post by phil.c » Mon Apr 10, 2017 9:41 am

Hi guys, I, m not seeing any fuel inside the carb when I hand operate the throttle.

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Re: Fuel Problem?

Post by artificer » Mon Apr 10, 2017 11:01 am

What have you been doing, loosening, cleaning, checking or replacing lately?
Phil wrote:Hi guys, I, m not seeing any fuel inside the carb when I hand operate the throttle.
If the vehicle is rarely used it is possible the needle valve is stuck closed & there is no fuel getting to the carburettor fuel bowl. Give that area a few good whacks with the plastic handle of a screw driver.

You can do as Joel suggests to see if there is fuel, but forget all that volume stuff @ this stage as it has absolutely nothing to do with starting issues, when one knows there is fuel getting to the carburettor.

If no fuel then there is most likely an air leak on the non pressure side of the fuel pump [this will not show as a fuel leak BTW] or no fuel in the fuel tank. You have checked?

Get yourself a $15.99 HF tool that has many uses including what mechanics do to check & quickly eliminate a fuel pump when problems like yours arise.
http://www.harborfreight.com/fuel-pump- ... 62637.html
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Re: Fuel Problem?

Post by phil.c » Mon Apr 10, 2017 11:25 am

Thanks, just to be clear when I manually pour some fuel down the carb barrel it fires up straight away and then the carb kicks in and performs as it should. It just seems when I first try to start it the carb doesn't supply any petrol.

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Re: Fuel Problem?

Post by artificer » Mon Apr 10, 2017 11:39 am

You must be getting fuel then.
With this Carter carburettor when starting use a little choke [not needed in warm weather] 2 pumps of the accelerator pedal & it should fire up straight away, when the tune is good.

If this procedure doesn't work, a teaspoon of fuel gets you going, then all is fine except when you try to accelerate & the vehicle misses when you hit the pedal there may be an issue with the accelerator pump.
So once everything else simple checks as OK you need to address the fuel pump issue.

It should get enough fuel to start with full choke no matter what the fuel pump is doing, though!
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

phil.c
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Re: Fuel Problem?

Post by phil.c » Tue Apr 11, 2017 10:43 am

Thanks for your reply, took carb apart and found the plunger was stuck. Probably due to sitting all winter.


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