Fuel pressure issues

[dirtybird#7]

Hi all, trying to sort out an issue on my 70 RR where fuel sprays out of my carb air vents after some hard driving and once the engine is up to operating temps and essentially chokes out the engine. It will only fire back up once it’s had a chance to cool down. I do have an external and in line electric Malory fuel pump with no return line and my fuel regulator is keeping between 4-6 psi. I think it may be fuel pressure build up in the tank as I have a non vent cap. Would it be as simple as replacing the cap with a vented one or drilling a small hole in my current cap? I’m running a ProFom 750 4 barrel double pumper carb (same as a holly 4150). Here’s a pic of the carb with circles around where the fuel is spraying out. I think these are simply air vent tubes for the float bowls located directly behind the metering block, my guess is the pressure is unseating the needles allowing the gas to escape.

 

[Ranger]

Have you checked your float level adjustment?

 

[dirtybird#7]

Yes set it in the middle of the window.

 

[dirtybird#7]

well that wasn’t it, as soon as she heated up she choked out and puked fuel through the carb vents, sitting on the side of the road letting her cool...I swear at my wits end on this one.

 

[Russ69Runner]

This is sounding like you might need to put a return line in. Don't know if the vapor lock bowl would help you or not. If you read some of the Manual's here that might give you a good idea of what you might be having a problem with. Had a problem with a Holley one time and called the company. This is something I would do They may have a good answer or suggestion's on how to stop this. Can relate to your frustration when we work so hard to keep these car's running like we want. Hope these ideas will help ya.

 

[dirtybird#7]

Thanks Russ69Runner return line could definitely be in the cards

 

[Russ69Runner]

My Holley was doing the same thing and it ended up being the float's where old. They may have a stronger needle valve for the bowl. I know you have window's on your bowl's maybe try to raise the fluid level a bit higher and see if that help's. Just thinking out of the box. But would call the carb company and express the problem to them. That is always the first thing I do to help resolve issues. Man hope you get it fixed buddy. Nothing worst than a motor that dose not work rite.

 

[dirtybird#7]

I took off a Holly 4150 4-barrel because it was old and in bad shape and I was too lazy to rebuild it, rethinking that strategy LOL

 

[Russ69Runner]

Oh the pain of it all!!!!! Don't trash that one yet Give those guy's a call.