fuel problems.... (too much of it..)

[undy]

Well ....... finally got a chance to take an extended ride with the new 482" KC Pond S/O in 80 deg+ weather yesterday. Lemme say .... t'wasn't any fun. It took 6 break-downs (flooded carb) on the bumper-to-bumper interstate/side roads to get the Cobra back home. I sure hope I don't have any ring/cylinder scoring from the washed down cylinder walls.

I think two basic things are causing this..

1. The elevated temps under the hood caused by higher outside temps and the in-depth inlet radiator shroud I installed that keeps air from bypassing the radiator. The air that used to bypass the radiator kept under-hood temps down, which no longer happens. This would aggravate an already rich condition.

2. I had repiped the fuel system with a larger electric pump and a new 8AN single pipe system when I installed the 482. With the engine off or idling w/the fuel pump running the fuel pressure starts at 6psi and slowly creeps up to 15 psi. It eventually overcomes the Holley 950HP's bowl float needle valves and dumps fuel in the engine and on top of the engine (not cool or safe either).

My thought process leads me to the following corrective measures:

1. Redo the fuel system to have a bypass type regulator, run new return line back to the tank and make a bypass system that WILL maintain the mandated 6-7 psi. This should also keep the fuel actually cooler as it enters the carb too.

2. Remove the carb and disassemble to ensure no debris is present in the bowls, needle valves, orifices and jets.

3. Not much I can do with engine heat (turkey pan maybe??) I can either have a cool radiator/engine or a cool carb/fuel lines, not both. I won't cross this bridge unless I need to. I'm thinking the other remedies should take care of the problem anyway.

I'm very interested hearing other's thoughts and experiences along these lines..

Dave

[blykins]

I would just install an inline regulator.....a $30 Holley regulator worked fine for me. I think the needle coming off the seat is really your only problem.

Also, I'd change the oil just in case...gas will break down the oil and etch the bearings.

[RedBarchetta]

Originally Posted by undy

I can either have a cool radiator/engine or a cool carb/fuel lines, not both.

Why not? You can:
1) run a base isolator shield between the carb and intake
2) insulate your fuel lines with heat wrap material
3) install a cool can if you're that concerned about warm fuel

Looking at your pics in the gallery, you're feeding the beast from the firewall side, so I don't see where hot fuel is an issue?

I believe you can also use a fuel pressure regulator without the need for a return line. I suppose the return line reduces the stress on the electric pump, but a lot of guys don't run return lines and I haven't read a lot about the need for that on this forum.

I'd also ditch that glass, see-through fuel filter. That's a weak link on so many levels.

-Dean

[blykins]

Dean's right...I'm not using a return line with my electric pump.

[undy]

Originally Posted by blykins

I would just install an inline regulator.....a $30 Holley regulator worked fine for me. I think the needle coming off the seat is really your only problem.

Also, I'd change the oil just in case...gas will break down the oil and etch the bearings.

I have a current new regulator, single line 2 port Holley "big port" regulator. The pressure still creeps. That's why I'm going with the bypass type w/return.

Roger that on the oil change...

[undy]

Originally Posted by RedBarchetta

Why not? You can:
1) run a base isolator shield between the carb and intake
2) insulate your fuel lines with heat wrap material
3) install a cool can if you're that concerned about warm fuel

Looking at your pics in the gallery, you're feeding the beast from the firewall side, so I don't see where hot fuel is an issue?

I believe you can also use a fuel pressure regulator without the need for a return line. I suppose the return line reduces the stress on the electric pump, but a lot of guys don't run return lines and I haven't read a lot about the need for that on this forum.

I'd also ditch that glass, see-through fuel filter. That's a weak link on so many levels.

-Dean

The pics are old and the fuel lines are different now, no ghey glass bowl fuel filters now..

The return/bypass system will keep the fuel in the lines the temp of the fuel in the tank. (constant recirc)

When the supply line's "dead-headed" with no return there's always the propensity for escalating fuel pressures. The pressure would also creep with the Cobra's old single pipe fuel system too (different pump, filter, lines, regulator, carb and fittings)

I did just added Holley's new .260" thick carb/ fuel bowl spacer/insulator to my order. All I have is a little more than 1/4" between the top of the air cleaner and hood. It "should" help too.

[D-CEL]

Dead-head regulators can creep, big time If you run a big pump. The constant high load will also kill the pump faster. I like a return style fuel system. They can be a pain to plumb depending on your tank config. but worth it in my opinion.


Jason

[undy]

Got the new return system plumbed in and done. I also have the carb base insulator/heat shield installed. No more flooding or even rich running for that matter. She runs better than ever. It's amazing how well it'll run when it has the right amount of fuel at the right time..

Now the fuel sending unit's not reading right. It took some jolts with the tank removal. Luckily there's an inspection plate in the trunk over the sending unit . It won't be bad to access. It'll give me something to do in my spare time...