fuel pump pressure gives flooding??

[Route--66--]

Hi
I fitted a new mechanical fuel pump last week to my '65 200ci with Autolite 1100 single barrel, went out for a run with everything working ok.
Yesterday started it with difficulty, it ran very roughly then stalled as soon as I tried to move it.

Looked down barrel of the carb to see if petrol was present and even though the engine was off, petrol was still pouring into the carb through what I assume was the main jet and kept doing so for at least a minute or 2! So it was obviously flooding the engine like mad.
So it appears that
The fuel pump is pushing so much pressure that it's forcing petrol past the float chamber needle even when it's full, and even after the engine has stopped.
I confirmed the retention of pressure by unscrewing the filter cannister on top of the pump (pic of pump below) with the engine off - petrol shot out at pressure!

SO ... Rockauto are shipping me another pump totally for free -

As the petrol pump is new I assume it HAS to be that at fault and not anything to do with my carb..

Has anyone heard of that before / is it a defective pump or is my carb float too 'weak' to hold the pressure back?? (or other??!)
(just seems too much of a coincidence for it to not be the pump at fault when I've never had this problem before)

Thanks all

 

[drag-200stang]

Your new pump probably has more pressure because the spring is new. The lever doesn't pump the pressure. It compresses the spring and the spring does the pushing. It could have more spring pressure than a Ford spec stock pump but, I doubt it. Most likely your carb doesn't like the new higher pressure that your old wore out pump didn't have. Good chance taking the lines apart got debris holding the needle open. I guess you could rebuild the carb or install a regulator to reduce pressure. Good luck.

 

[Route--66--]

Thanks mate
I have been wondering about some crud being caught in the needle .. so you saying that makes me consider that too .. hmm.. think I'll take the top off the carb and have a look .. don't want to do a strip down as the carb works well otherwise ..
Thanks for that

 

[jimlj66]

Is that the fuel pump you installed? I don't think that is the proper pump. My fuel pump does not have the canister on it, nor does the pump I have on the shelf I removed from a '82 Mercury Zephyr with a 200. I guess there could be other styles used???

Edit.. I just did a quick google search and the pictures that came up all looked like the one on my '66, no filter canister.

 

[CobraSix]

jim,

You can run either style. Without the canister, you need a filter before the carb. With the canister, you end up with more filter and I don't run another filter before the carb.

 

[rbohm]

8) i doubt that the pump is the problem. even on older nascar engines that used the stock type pumps, you never saw more than about 9psi fuel pressure. as indicated chances are that you have a bad needle and seat. perhaps they are dirty, or the needle is worn out. it is also possible that the float is losing buoyancy as well. if the float is brass, shake it and see if fuel has gotten into the float. if the float is plastic, just go ahead and replace it.

 

[Route--66--]

Thanks guys
I will go ahead and take the top off the carb this weekend as it looks like something stuck in the needle is looking to be the most likely candidate ..
Thanks again!
D

 

[Route--66--]

Rbhom you're a star!
took the top off the carb this morning, float off.. needle out and what was sitting there a nice new shiny piece of swarf!.. must have come from the new pump after the filter !..
took it out, put it all back together and JOB DONE!!!!!
Ran really rough to start with from cold, as thought a couple of cylinders weren't firing and when I drove it off for the first time there was what sounded like a slight backfire thru the carb when I hit the throttle .. but after maybe a minute it was running totally smooth.
So, cheers again all !!!!

 

[chad]

swarf
hafta look around for onea those, must B on dis sidea the pond too...

What was the carb "cough" from? was it a true back fire or just a stumble in the carb? (Just thinkin ahead to some other potential problem. But , as U know, the fellas around here always say "Chad, there U go again, thinkin. You shouldn't oughta do that! All ways trouble.").

 

[Route--66--]

sorry.. swarf is like metal flakes or shavings over here .. it was a just a small piece of metal maybe just a couple of millimetres in diameter..
Noooo idea what the cough was about, it's never done it before .. am just hoping it was a result of the carb 'settling' back in afer I'd had the top off.. it actually was more like a cough like you say rather than a backfire .ie like back-pressure being coughed back up thru the carb ... will keep an eye on it though..
Cheers!
D

 

[bubba22349]

Ran really rough to start with from cold, as thought a couple of cylinders weren't firing and when I drove it off for the first time there was what sounded like a slight backfire thru the carb when I hit the throttle .. but after maybe a minute it was running totally smooth.

You were right to think a couple cylinders weren't firing! With the carb flooding because of the swarf the excess fuel going into cylinders fowled the plugs and it took some time and the heat from the engine running to clean them off so they would fire again, Good job

 

[chad]

Ahhh...
leave it to me mate Bubs, all ways got the scoup.
Good on ya!
(must B some swarf in Cali too).

 

[bubba22349]

(must B some swarf in Cali too).

If there is I never seen or heard of it before today, of course we have the same stuff too I just call it crap or crude.

 

[Route--66--]

Just started it from cold today and ran fine. So guessing you're right on the flooded plugs thing ! Cheers!
D