Hot engine hard to re-start Vapor Lock???

[cobrakidz]

I put a rebuilt Holley on my 289 and it now has the same problem--hard to start after it gets hot and sits for a little while. The starter spins fine (high torque) but the car just won't start. I might try a heat shield before I give up and change the carb again.

[lambogriff]

Hello all ,

the "Hot start Problem" is very well known by TVR-Owners . But there is a functional and cheap solution , that will help eliminating this problem . Take a look at the following site : " Mod-Wise.CO.UK "
Good luck !

Greets from Germany

lambogriff

[Dinobyte]

Originally Posted by BDR879

Dino,

I'm working through the same issue on my BDR and this option is the next on the table. A couple of Q's for you:

- Does your return line loop back from the carb back to the tank (long loop) or is it routed from the outlet of the elect pump back to the tank((short loop)?
- What elect pump did you use?
- Does the elect pump flow through the mech. pump?

Thanks

The loop back is from the carb to the tank.

Holley 12-801-1
Holley 12-801-1 - Holley Red Electric Fuel Pumps - Overview - SummitRacing.com

The electric pumps through the mechanical pump.

[BAsque1]

Hi All:
Changed the starter for a high torque wrapped it inside a heat shield, timing is fine, battery cable has the appropriate gauge for a trunk installed battery. Battery is 6mos old. Change the inline filter element and was a big improvement, also eliminated the gas preassure regulator also helped quite a lot. Just got the 1/2" (not much clearance there) phenolic spacer and will e installed this coming weekend. Will keep you guys posted. Running temp is between 180F-220F except today which were hitting the 100F mark not moving it out.

[BDR879]

Sounds like great progress. Sounds like your engine temps are solid and in the proper range from what I can gather from other FE owners.

Next week my car is going in for:

1) dyno tune and proper carb setup. Apparently if the system is running lean, the engine will run hot. The car had never been tuned and it will be worth the $300 to see if that's compounding my issue.

2) 1/2" phenolic spacer installation

3) Re-plumbing the fuel line from the firewall to the carb with braided hose (currently have tubing) and covering it with heat shielding where applicable.

If the above does not work, I will go the electric pump and recirc to the tank route similar to Dinobyte's.

Good luck and keep up posted

[BDR879]

Originally Posted by Dinobyte

The loop back is from the carb to the tank.

Holley 12-801-1
Holley 12-801-1 - Holley Red Electric Fuel Pumps - Overview - SummitRacing.com

The electric pumps through the mechanical pump.

Perfect....thanks!!

[snakebittexan]

I have the carb heat shield. Paid $27.00 for it, you can have it for $20.00 plus shipping cost. I installed a phenolic spacer.
Holley 108-70 - Holley Carburetor Heat Shield

[BAsque1]

OK guys here it is the report:
Installed the 1/2 phenolic spacer (easy job) tested the car twice for over an hour driving and starts like a charm, I would say problem solved.Tks to all you guys with your valuable solutions.
Cheers
Lou

[Michael C Henry]

Years ago I experienced vapor lock. Carb floats regulate liquid not vapor (boiling gasoline). Gasoline vapors spilling all over the from the float bowl vents. Most fuel pumps move fluid not vapor and when hot gasoline has the presure reduced by pumps pulling rather that pushing, gasoline can seperate from liquid into vapor. I went to a higher presure and volume fuel pumps (maybe too much higher) mounted low just infront of fuel tank sump. But the thing I used at the time was A BG diaphram adjustable fuel log . I mounted it on the right side close to the carb inlets with short connectors to dual carb single inlets. Adjustable outlet spacing, adjustalble presure (6 psi). I ran a hose from the rear fire wall forward and turned it to enter the fuel log at the front. Fuel circulates rearward down the fuel log. The return type diaphram adjustable fuel presure regulator is now located at the rear of the fuel log. It holds back 6 psi and returns over supply fuel to tank. Always fresh cooler fuel from tank available (circulating) just about a couple of inches from carb inlets. All wrapped in reflective heat barrier material. Bg seems to have gone under but there are lots of fuel product manufacturers still out there. The BG fuel log has never given me any problems. I do nont know what I'll do if it ever does.

[Michael C Henry]

Years ago I experienced vapor lock, of sorts. Carb floats regulate liquid not vapor (boiling gasoline). Gasoline vapors spilling all over the from the float bowl vents. Most fuel pumps move fluid not vapor and when hot gasoline has the presure reduced by pumps pulling rather that pushing, gasoline can seperate from liquid into vapor. I went to a higher presure and volume electric fuel pumps (maybe too much higher). I mounted the fuel pumps low just in front of the fuel tank sump. But the thing I used at the time was A BG diaphram adjustable fuel log . I mounted it on the right side close to the carb inlets with short connectors to dual carb single inlets. Adjustable outlet spacing, adjustalble presure (6 psi). I ran a fuel hose from the fire wall forward and turned it to enter the fuel log at the front. Fuel circulates rearward down the fuel log. The return type diaphram adjustable fuel presure regulator is now located at the rear of the fuel log. It holds back 6 psi and returns over supply fuel to tank. Always fresh cooler fuel from tank available (circulating) just about a couple of inches from carb inlets. All wrapped in reflective heat barrier material. Bg seems to have gone under but there are lots of fuel product manufacturers still out there. I have never had any problems with this BG fuel log. I do not know what I'll do if and when it does.

[Michael C Henry]

Years ago I experienced vapor lock of sorts. Carb floats regulate liquid not vapor (boiling gasoline). Gasoline vapors spilling all over the from the float bowl vents. Most fuel pumps move fluid not vapor and when hot gasoline has the presure reduced by pumps pulling rather that pushing, gasoline can seperate from liquid into vapor. I went to a higher presure and volume fuel pumps (maybe too much higher). I mounted the electric fuel pumps low just in front of the fuel tank sump. But the thing I used at the time was a BG diaphram adjustable fuel log . I mounted it on the right side close to the carb inlets with short connectors to the dual carb single inlets. Adjustable outlet spacing, adjustalble presure (6 psi). I ran a fuel hose from the fire wall forward and turned it to enter the fuel log at the front. Fuel circulates rearward down the fuel log. The return type diaphram adjustable fuel presure regulator in this configuration, is located at the rear of the fuel log. It holds back 6 psi and returns over supply fuel to tank. Always fresh cooler fuel from tank available (circulating) just about a couple of inches from carb inlets. All wrapped in reflective heat barrier material. BG seems to have gone under but there are lots of fuel product manufacturers still out there. I have never had any problems with this BG fuel log. I do not know what I'll do if and when it does.

[PDUB]

Originally Posted by Michael C Henry

Years ago I experienced vapor lock. Carb floats regulate liquid not vapor (boiling gasoline). Gasoline vapors spilling all over the from the float bowl vents. Most fuel pumps move fluid not vapor and when hot gasoline has the presure reduced by pumps pulling rather that pushing, gasoline can seperate from liquid into vapor. I went to a higher presure and volume fuel pumps (maybe too much higher) mounted low just infront of fuel tank sump. But the thing I used at the time was A BG diaphram adjustable fuel log . I mounted it on the right side close to the carb inlets with short connectors to dual carb single inlets. Adjustable outlet spacing, adjustalble presure (6 psi). I ran a hose from the rear fire wall forward and turned it to enter the fuel log at the front. Fuel circulates rearward down the fuel log. The return type diaphram adjustable fuel presure regulator is now located at the rear of the fuel log. It holds back 6 psi and returns over supply fuel to tank. Always fresh cooler fuel from tank available (circulating) just about a couple of inches from carb inlets. All wrapped in reflective heat barrier material. Bg seems to have gone under but there are lots of fuel product manufacturers still out there. The BG fuel log has never given me any problems. I do nont know what I'll do if it ever does.

Originally Posted by Michael C Henry

Years ago I experienced vapor lock, of sorts. Carb floats regulate liquid not vapor (boiling gasoline). Gasoline vapors spilling all over the from the float bowl vents. Most fuel pumps move fluid not vapor and when hot gasoline has the presure reduced by pumps pulling rather that pushing, gasoline can seperate from liquid into vapor. I went to a higher presure and volume electric fuel pumps (maybe too much higher). I mounted the fuel pumps low just in front of the fuel tank sump. But the thing I used at the time was A BG diaphram adjustable fuel log . I mounted it on the right side close to the carb inlets with short connectors to dual carb single inlets. Adjustable outlet spacing, adjustalble presure (6 psi). I ran a fuel hose from the fire wall forward and turned it to enter the fuel log at the front. Fuel circulates rearward down the fuel log. The return type diaphram adjustable fuel presure regulator is now located at the rear of the fuel log. It holds back 6 psi and returns over supply fuel to tank. Always fresh cooler fuel from tank available (circulating) just about a couple of inches from carb inlets. All wrapped in reflective heat barrier material. Bg seems to have gone under but there are lots of fuel product manufacturers still out there. I have never had any problems with this BG fuel log. I do not know what I'll do if and when it does.

Originally Posted by Michael C Henry

Years ago I experienced vapor lock of sorts. Carb floats regulate liquid not vapor (boiling gasoline). Gasoline vapors spilling all over the from the float bowl vents. Most fuel pumps move fluid not vapor and when hot gasoline has the presure reduced by pumps pulling rather that pushing, gasoline can seperate from liquid into vapor. I went to a higher presure and volume fuel pumps (maybe too much higher). I mounted the electric fuel pumps low just in front of the fuel tank sump. But the thing I used at the time was a BG diaphram adjustable fuel log . I mounted it on the right side close to the carb inlets with short connectors to the dual carb single inlets. Adjustable outlet spacing, adjustalble presure (6 psi). I ran a fuel hose from the fire wall forward and turned it to enter the fuel log at the front. Fuel circulates rearward down the fuel log. The return type diaphram adjustable fuel presure regulator in this configuration, is located at the rear of the fuel log. It holds back 6 psi and returns over supply fuel to tank. Always fresh cooler fuel from tank available (circulating) just about a couple of inches from carb inlets. All wrapped in reflective heat barrier material. BG seems to have gone under but there are lots of fuel product manufacturers still out there. I have never had any problems with this BG fuel log. I do not know what I'll do if and when it does.

Is there an echo in here?

[BAsque1]

Ok Guys, here is an update:
after installing the phenolic spacer, removing the useless fuel regulator (I have a mechanical gas pump) changing the filter element the car is doing fine. If it gets too hot after a hard drive, I pump the accelerator 2-3 times and its starts fine. I guess it is a malady germane to Cobras and we kind of have to work around it. I still love my snake.
Cheers
Lou

[windsor 351]

If your motor turns over fast like normal and won't fire, sounds like a fuel issue.
If it turns over slow and lethargic it might be a starter issue if your are running over 10-1 compression. I had the same issue with my stroker 347. A gear reduction starter fixed that prob. Never had any issues since..