Flooding and Hot Start

[amdavidson]

My 38/38 seems to be having issues.

It idles well seems to drive well, but is having a lot of issues with hot starting.

I'm currently running two fuel filters, one before and after the stock mechanical pump. After letting the car sit while warm, I can see both filters start to empty. At first I thought this was a vapor lock issue, but it's not all that hot here, I'm running the phenolic spacer and it doesn't seem to go away with application of cool water.

I pulled the top of the air filter and looked down the carb and the driver side throat was full of fuel and I could see it dripping in. Assuming it was a float issue, I adjusted the floats again, probably a bit conservative on the shut off to see if I could really get the needle valve to close when the float bowl was full.

But it's still doing it.

I'm not running a fuel pressure regulator, and have no idea of what the pressure is. I'm just running a straight line from the pump to the fuel filter to the carb.

How do I ensure that the needle valve is closing? I read about sinking floats, is there a way to test this? I read my weber carb manual and it doesn't seem to be too helpful in this case.

Thanks for any ideas.

EDIT: The car will start after this happens with WOT and a little extra cranking, but she sure doesn't seem to like it.

[amdavidson]

Oof... No replies.

Let's see if a little bump to the top gets me any suggestions.

[Colin]

Do you have the return line hooked up? On carbed cars, I believe there is a "didta" valve so something to that effect, which takes excess fuel and runs it via the metal return line under the battery box. I disconnected this valve once, back when my car was carbed, and I had the same symptoms which you are describing now.

[PatAllen]

right after you stop the engine disconnect the fuel line that goes to the carb and see if the throat gets still full of gas.

maybe there is over pressure in the feed line from the pump and the needle/float just dont cope with it so the bowl gets overfilled...just a thought.

or the needle/float adjustment or just the needle is crap...

[amdavidson]

Do you have the return line hooked up? On carbed cars, I believe there is a "didta" valve so something to that effect, which takes excess fuel and runs it via the metal return line under the battery box. I disconnected this valve once, back when my car was carbed, and I had the same symptoms which you are describing now.

I do not have the return hooked up, it's sealed off with a bolt and a hose clamp.

The valve for the return is vacuum activated if I'm not mistaken, and I don't have any vacuum ports on my cannon manifold to use with it.

Or is there another way to set it up that I don't know about?

[amdavidson]

The needle is brand new, but I'll try pulling the line to the carb.

I suspect that it's over pressuring the needle valve like you say, but I was surprised to see it because I've seen cars that run the same fuel routing as I with the mechanical pump and don't see over pressurizing.

Should I be looking at getting a bypass regulator if over pressurizing seems to be the issue?

[PatAllen]

The needle is brand new, but I'll try pulling the line to the carb.

I suspect that it's over pressuring the needle valve like you say, but I was surprised to see it because I've seen cars that run the same fuel routing as I with the mechanical pump and don't see over pressurizing.

Should I be looking at getting a bypass regulator if over pressurizing seems to be the issue?

you can use an old Jeep fuel filter, the "over pressure" is built on it. It has 3 nipples, 2 large (in/out) and a small one (return). i know its not oem, but it will work and is damn cheap. ask for a 1977 CJ7 filter. 5$ at local parts store.

[amdavidson]

you can use an old Jeep fuel filter, the "over pressure" is built on it. It has 3 nipples, 2 large (in/out) and a small one (return). i know its not oem, but it will work and is damn cheap. ask for a 1977 CJ7 filter. 5$ at local parts store.

That looks like a great solution, I don't place much importance on OEM. Functionality and simplicity win out for me.

How are you guys stepping up from the 6mm fitting on the pump to the 8mm fitting on the Weber carb?

I'm currently using a filter with a 1/4" fitting and 5/16" fitting on opposite ends to do that, but this filter has 5/16" on either end and would be installed in the same place. Two fuel filters I can dig, three is starting to get excessive.

Any thoughts?

[amdavidson]

Just to report back and close this thread I'd like to say that the G3583 filter worked wonderfully and solved all of my issues.

If anyone finds this in the future with the same issues give it a shot.

[strorg]

how did you return to the fuel tank? my '71 has an unused return line but it is routed to a plastic expansion tank in the trunk, which is routed to the fuel filler neck. i don't think this is suitable for a liquid return, but i suppose i could eliminate the expansion tank.

or can i just dump it back into the supply line from the tank, before the fuel pump?

[amdavidson]

On my 75, there are two plastic lines and a hard line.

One plastic line is fuel that is sucked from the tank by the mechanical pump under the hood. The other plastic line comes from the evap system and it's unused. There's also a metal hard line running down the frame rails on the driver side of the car that I used for the return.

Everything seems to still be running great with that setup.

[eurotrash]

I'm diggin' this solution. Now maybe I can switch to this and ditch the stock vacuum pot recirc system. In the "every little bit helps" mind set, its the last of the smog gear that I haven't had the heart to eliminate for the sake of cool fuel.

[eurotrash]

Got these new at a swap today for a dollar each!

should work just the same..!?

[amdavidson]

Looks absolutely identical to the one that I have. I havent been able to find any information as to how much pressure it will build up before it starts diverting though. So watch for emptying of the float bowl.

I havent seen any issues like that with the Fram version. Just went on a long sporting drive through the hills about an hour ago and she ran like a dream.

[eurotrash]

So finding that filter in a box of random parts was humorous..for a buck, i couldnt pass it up. But this morining I read up on the function of the little guy and found this.. So I'm not sure of the benefit for my usage..

UPDATE: in digging further in the jeep forum, it does prevent vapor lock, but I con't find info on whether it recirculates all the time.. like when the floats close the valve. Still digging..

UPDATE 2:

Here's a pic with a 32/36. this is how I imagined using it, only before the pump.

It appears that it does what we need, just make double sure to install it with the return line in the 12 O'clock position..