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1946 Plymouth fuel pump..help!


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yugprahs
New User

Mar 2, 2010, 2:15 PM

Post #1 of 12 (4878 views)
1946 Plymouth fuel pump..help! Sign In

Hi. New to forum. Glad I found ya'll! I have a 1946 Plymouth Special Deluxe 2 dr. sedan, flat six and bought the car not running... fuel flow problems. The car had set up for years and fuel tank was a mess. I cleaned and relined tank and replaced all fuel lines. I still had no fuel to the carb. I bypassed mechanical fuel pump with a a 6 volt model E8011 (seems to be the common one everybody carries) electric pump. 4 to 6 psi, 30 gph and recommended for my car. Wired it to come on when I turn on the ignition switch. (On a 46, you then have a separate push button to start). Have fuel now, apparently mech. pump was bad.

Now comes the problem. Since the pump runs all the time once I turn on the key, I assumed (I know..lol) that once the carb bowl was full and the needle valve for the bowl closed, that the pump would shut off until the needle valve opened again. The reason I thought this is that there is a small part attached to the new fuel pump that I thought was a pressure regulator or switch of some type. It actually looks more like a small filter. Anyway, I think the pump pressure is overcoming the carb bowl float beacause when the pump is on I have fuel forcing its way out of every nook and cranny in the carb and am in constant flooded condition. I am actually dripping gas all over the place now.

I might add, just to give all info, the carb looks like it had a kit sometime in the past and screws are tight but fuel is even seeping around the (new looking) gaskets. I had palanned on sending caeb off for rebushing, surface planing once I have other issues resolved. Car does run for a short time with no carb leaks if I just leave the pump off and manually fill carb bowl. Just wanted to give all info I could.

So I have gone from one extreme to the other...lol.

Any thought s from you old car gurus?

link removed


(This post was edited by Hammer Time on Mar 2, 2010, 6:14 PM)


re-tired
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Mar 2, 2010, 9:32 PM

Post #2 of 12 (4866 views)
Re: 1946 Plymouth fuel pump..help! Sign In

The pump should go to a self bypass or neutral mode when the flow is stopped and the pressure reaches its set pressure. The needle and float(s) should be able to stop the flow . PROVIDED their not gummed up or trash in the seat. Take the top off the carb a have a look see. If your not carb savy take digital pics and take notes at each step.


LIFE'S SHORT GO FISH


yugprahs
New User

Mar 2, 2010, 10:12 PM

Post #3 of 12 (4861 views)
Re: 1946 Plymouth fuel pump..help! Sign In

Thanks re-tired. I thought the pump would go into a nuetral mode also. I have had the top off the carb several times previously to pour gas in the bowl manually just to fire her up and had even readjusted the float. But now that I actually have gas flowing from the tank, you are right, might have collected some trash. There was no paperwork included with the pump, but I noticed online it said it had a check valve? Would this be the same as a bypass or neutral mode?

If the trash theory doesn't pan out, could having the float set to high cause a problem?

Also, when I aquired the car I noticed a box with the old carb gaskets seats etc. in the trunk as if the carb had been gone thru.

I know just enough to make me dangerous...lol


re-tired
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Mar 2, 2010, 11:15 PM

Post #4 of 12 (4860 views)
Re: 1946 Plymouth fuel pump..help! Sign In

The check valve in the pump is to keep the fuel in the line going to the carb from draining back down when pwr is off and creating a siphon effect that would empty the bowl. Carefully check the needle and seat for the slightest flaw ,a crease line where point contacts seat , even a flake of varnish from the old gas.Use a magnifying glass and strong light. I once had a hair had passed halfway thru the needle/seat , gave a tiny leak that only became a problem during long idle. Also make sure gas cap is allowing tank to vent pressure , it can build in tank and icrease pressure at carb.I've always set my floats so that when the needle is pushed down ,(you may have to hold down the piviot point), the floats are parallel to carb houseing.


LIFE'S SHORT GO FISH


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 3, 2010, 2:18 AM

Post #5 of 12 (4857 views)
Re: 1946 Plymouth fuel pump..help! Sign In

Just a note on pumps: Most even when they stay running will not exceed the pressure rating as it's a spring that wont allow over, infinite pressure same as the mechanical ones.

Don't know this specifically but many old mechanical fuel pumps were also a vacuum pump on top and fuel on bottom if wiper or other things used vacuum motors instead of electrics. If so, you should be able to use manifold vacuum, storage ball (universal) and a check valve but wiper will quit (if vacuum motor) while going up hill or accelerating!

T



re-tired
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Mar 3, 2010, 8:46 AM

Post #6 of 12 (4845 views)
Re: 1946 Plymouth fuel pump..help! Sign In

Right you are old timer . The old straight 4's & 6's were low compession and low vacume engines. Thus the need for additional vac to run the vac wipers . I drove a 53 flat fender jeep for years. Had vac wipers. Everytme i would gun it to pass(you know your going too slow when passed by a flat head four )Anyway ,that's right when the wipers would stop. they had a little handle so you could manually move them at these times. There were also generators with vac pumps on rear . For the youngsters a generator was a un-rectified alternator that weighed about 50 lbs.


LIFE'S SHORT GO FISH


Tom Greenleaf
Ultimate Carjunky / Moderator
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Mar 3, 2010, 10:22 AM

Post #7 of 12 (4843 views)
Re: 1946 Plymouth fuel pump..help! Sign In

No shortage of "Old Phartness" here!

Vacuum motors! What are those? Hydraulic power windows - nah - really - YES! I actually know how to true a spoked wheel! Wooden ones - now you are beyond meWink

T



Loren Champlain Sr
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Mar 15, 2010, 6:53 PM

Post #8 of 12 (4809 views)
Re: 1946 Plymouth fuel pump..help! Sign In

yugprahs; I just looked up specs for your vehicle. Fuel pressure should be 3-4 psi. Looks to me, that the fuel pump that you are using is too much, over-riding the needle & seat.
Loren
SW Washington


yugprahs
New User

Mar 15, 2010, 7:06 PM

Post #9 of 12 (4805 views)
Re: 1946 Plymouth fuel pump..help! Sign In

Thanks for the info Loren. I looked for a lower psi pump and didn't find one. I am thinking about going back to the mechanical and using the electric ahead of it on a toggle switch just to prime after sitting and for vapor lock. I have heard of a lot of people doing this. In the meantime...been working to much...haven't had time to fool with her. I still want to send the carb off for refurbish when I can. Have it rebushed and surface planed, etc.


Loren Champlain Sr
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Mar 15, 2010, 7:10 PM

Post #10 of 12 (4803 views)
Re: 1946 Plymouth fuel pump..help! Sign In

>>just to prime after sitting and for vapor lock<< Hey, that's not a bad idea. Never heard that, before. Had a '40 Ford Coupe for many years and many flatheads. Vapor lock was a real problem. Wooden clothes pins on the fuel line helped, but not enough room for enough of them..LOL. Finally, went with an electric pump, like you. Mounted it back by the tank. Manual pressure regulator.
Loren
SW Washington


yugprahs
New User

Mar 15, 2010, 7:32 PM

Post #11 of 12 (4799 views)
Re: 1946 Plymouth fuel pump..help! Sign In

I did just find a lower psi 6v pos. ground pump,after replying to your post, but the bummer is that I can't return the one I bought. But, hell, I knew old cars were money pits when I bought my first one back in 19 hundred and dirt.



What did the clothespins do? Absorb heat?


Loren Champlain Sr
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Mar 16, 2010, 2:53 PM

Post #12 of 12 (4789 views)
Re: 1946 Plymouth fuel pump..help! Sign In

Clothes pins? LOL. Besides being able to dry my clothes while driving, they were 'supposed' to help dissipate the heat before entering the carbs???? (Two, 2-bbl Stromberg 194's). The last flathead that I had in there was bored .120 over. Cylinder walls were the thickness of paper, LOL. Always had a tough time keeping it cool, even with two water pumps (one in each side of the block).
Loren
SW Washington






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