Lack of power climbing a hill

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
csmarcher
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Lack of power climbing a hill

Post by csmarcher » Fri Apr 20, 2018 9:15 pm

I'm a bit puzzled here. I've just had a complete engine rebuild on my 42 Ford, and although me engine is running fine, it's struggling to get up a fairly long grade even in 2nd gear with my foot all the way down.
What if anything should I be looking at as a diagnosis ? I'm purging the fuel system, having the tank cleaned, the fuel filter replaced, and I'm considering replacing the fuel pump as well.

Any help, suggestions or advice would be very much appreciated


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Re: Lack of power climbing a hill

Post by artificer » Sat Apr 21, 2018 2:01 am

Hook in a vacuum gauge after first setting the point gap @ 0.020" or alternatively dwell @ 42* [both tell one the same thing one is mechanical the other is electrical] & see what the vacuum reading is. Let us know.
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.

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Re: Lack of power climbing a hill

Post by Joe Gopan » Sat Apr 21, 2018 3:38 am

It wouldn't hurt to check your accelerator pedal linkage adjustment to see if the carburetor is getting its full range of motion when the gas pedal is depressed.. The Throttle rod is adjustable. Your TM9-803 has a trouble shooting section. Read paragraph 71, 72 in your TM.
You can check the travel by disconnecting the rod at the carburetor and depressing the accelerator pedal and adjusting the rod to go thru the throttle lever in wide open position.
(Do this with the engine shut off)
Is your gas pedal bent (like in sway back?) It should be flat.
Last edited by Joe Gopan on Sat Apr 21, 2018 6:55 am, edited 2 times in total.
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Re: Lack of power climbing a hill

Post by dinof » Sat Apr 21, 2018 5:49 am

Since you mentioned it's a new engine, you may want to do a compression check, as well as check the timing. These 2 things are easy to do. Don't replace the fuel pump. Test your old one first. Easy to do also!
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Re: Lack of power climbing a hill

Post by Marty, SoCal » Sat Apr 21, 2018 6:49 am

I'm with Ben on this, first check to see if you are getting full throttle! Out of the last four or five old jeeps I've worked on, only one was getting full throttle! Sometimes it's wear in the linkage, but usually it was the adjustment that was off.
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Re: Lack of power climbing a hill

Post by Joe Gopan » Sat Apr 21, 2018 7:08 am

And how old is your fuel, E-10 can go bad in the gas tank while your Jeep is sitting unused. Mine has done that once over the years. The gas turned to a green slime in about 4 months during winter storage, even with Stabil.
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Re: Lack of power climbing a hill

Post by Chuck Lutz » Sat Apr 21, 2018 8:06 am

Try the linkage check first...when overhauling the motor, guys often add the rubber baffle where the pedal linkage goes through the firewall which can stop the full movement of the carb linkage.
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Re: Lack of power climbing a hill

Post by artificer » Sat Apr 21, 2018 11:14 am

I agree on the throttle adjustment/s not being right as a possibility especially after having an engine out.

Checking for wide open throttle is a part of any tune on these type vehicles.
How to:
Remove the 90* connection from the top of carburettor air horn.
Check & make sure the choke is right OFF when the choke cable is pushed fully home @ the dash.
Next, have someone fully depress the accelerator pedal & check the throttle butterfly, directly under the choke plate, in the carburettor throat is fully vertical, just under the the choke.
If it is not there is an adjustment issue & if it is, move on.
Takes a couple of minutes & costs nothing.
Never start fooling with fuel until one has eliminated all possible ignition problem sources.
Takes another few minutes & costs nothing.
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.

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Re: Lack of power climbing a hill

Post by Joe Gopan » Sat Apr 21, 2018 11:32 am

That's a lot of extra work when all it is necessary is to simply check and or adjust the threaded throttle rod to ensure the throttle is all the way open.
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Re: Lack of power climbing a hill

Post by JAB » Sat Apr 21, 2018 1:45 pm

I don't disagree with the advice provided so far, but want to share an experience that may help. I once had a problem with the master cylinder on my CJ that didn't allow the brakes to retract all the way after things warmed up. It was just a slight drag, and not all that noticeable until you tried to go up a long hill and needed more power. Did you replace the master cylinder heat shield after re-installing the engine? Are (any of) the wheels warm to the touch after a drive? Easy to check and could cause the same symptoms.
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Re: Lack of power climbing a hill

Post by dinof » Sat Apr 21, 2018 5:23 pm

The brakes will be warm after driving around. Or at least when I drive my jeep it is city driving. Many stops & go between lights. THAT will warm the drums. Now a drum that is Very hot to the touch is another thing. But like jab said, easy to check / confirm that no drag is going on.
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Re: Lack of power climbing a hill

Post by JIMN » Sat Apr 21, 2018 6:00 pm

Ok, here might be the obvious....
Perhaps the hill is just that steep. Do you know of another similar vehicle in the area that you could compare yours to? There are hills where I live that are rather tough for a ww2 jeep. I imagine California has plenty.
Did it go up the hill better before you rebuilt it? Or is this the first time you have tried that hill.
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Re: Lack of power climbing a hill

Post by Joe Gopan » Sun Apr 22, 2018 8:18 am

Does your brake pedal get harder as you drive the Jeep?
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HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
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Re: Lack of power climbing a hill

Post by Chuck Lutz » Sun Apr 22, 2018 10:15 am

A friend complained once that when he drove his recently rebuilt GPW down a long stretch of road with a slight incline against another well-running jeep that the other jeep blew his doors off (parenthetically speaking as if the jeep had doors!).

Following the Golden Rule to check the easiest thing first...
I told him to remove the cotter pin holding the throttle linkage rod to the Carter throttle and to check the amount of "throw" the Carter throttle had. He then held the maximum amount of throttle on the Carter and moved the loose throttle linkage rod back and forth to ascertain what "maximum throw" would be.....he found that the linkage was no where NEAR accentuating the Carter throttle to "FULL".

I told him to unscrew that throttle linkage from the pivot block until he was just about at the end of the threads on it and to repeat the above test.
Now he had achieved FULL THROTTLE on the Carter!

I think having to mess with just ONE COTTER PIN to do that test is the least intrusive.

FYI....if you run out of threads on that rod before it achieves the length to match the Carter throttle attaching hole, then check to see if the boot on the pedal linkage is obstructing full depression of the pedal.
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Re: Lack of power climbing a hill

Post by artificer » Sun Apr 22, 2018 1:00 pm

artificer wrote: ↑22 Apr 2018, 05:14

Checking for wide open throttle is a part of any tune on these type vehicles.
How to:
Remove the 90* connection from the top of carburettor air horn.
Check & make sure the choke is right OFF when the choke cable is pushed fully home @ the dash.
Next, have someone fully depress the accelerator pedal & check the throttle butterfly, directly under the choke plate, in the carburettor throat is fully vertical, just under the the choke.
If it is not there is an adjustment issue & if it is, move on.
Takes a couple of minutes & costs nothing.
Never start fooling with fuel until one has eliminated all possible ignition problem sources.
Takes another few minutes & costs nothing.
Above the amateur method. :roll:
Ben Dover wrote: ↑22 Apr 2018, 05:32
That's a lot of extra work when all it is necessary is to simply check and or adjust the threaded throttle rod to ensure the throttle is all the way open.
Thaty's how hands on mechanic does it :P
Same goes for the chocke :wink:

Luc

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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.


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