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Anyone ever heard of this on carbureted engines?
Fuel line insulation to remedy vapor lock?
- Thread starter The motor guy
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I have never had vapor lock on any carbureted engine.
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I've been having issues with poor re starting when hot, you have to give it throttle to get it to restart, then it runs a tad rough for 10 seconds or so
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You would think on a hot engine it would start back up without having to pump it.
Originally Posted by motor_oil_madman
Anyone ever heard of this on carbureted engines?
I know a few people in the early 70's who used it when I first became a car enthusiast. Some said it helped.
Anyone ever heard of this on carbureted engines?
I know a few people in the early 70's who used it when I first became a car enthusiast. Some said it helped.
Fairly common in the marine world.
See if you can install a check valve, similar to this: http://www.boatfix.com/merc/Bullet/99/99_07.pdf
I've also heard of people using heat wrap tape with some success: Heat Wrap Tape on eBay
See if you can install a check valve, similar to this: http://www.boatfix.com/merc/Bullet/99/99_07.pdf
I've also heard of people using heat wrap tape with some success: Heat Wrap Tape on eBay
Originally Posted by motor_oil_madman
Anyone ever heard of this on carbureted engines?
Yes, absolutely.
Several decades ago, when I lived in Phoenix, I had vapor lock issues with a 70 Pontiac during the summer months. I split a rubber fuel line and slipped it over the hard line from the pump to carb and had no more issues. Todays gas is worse. My 66 (signature) would boil the gas whenever outside temps were in the 90s until I made some insulators to install under the carbs.
Anyone ever heard of this on carbureted engines?
Yes, absolutely.
Several decades ago, when I lived in Phoenix, I had vapor lock issues with a 70 Pontiac during the summer months. I split a rubber fuel line and slipped it over the hard line from the pump to carb and had no more issues. Todays gas is worse. My 66 (signature) would boil the gas whenever outside temps were in the 90s until I made some insulators to install under the carbs.
Yep, was common. My mother and brother barely made it to a funeral on a hot day, because of her '77 Impala vapor-locking.
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It is on a boat with a 350 and Holley carb. A buddy of mine showed me how the fuel lines go along the block on each side of the front of the carb and are very close to the engine. I'll try the split fuel line trick the other poster mentioned to put over the steel lines.
All you have to do is keep the fuel in the float bowls cool by installing a heat shield.
![[Linked Image]](https://joeysmusclecars.com/wp-content/uploads/2016/08/na9-7.jpg "[Linked Image]")
While it may be vapor lock it could be a plethora of other issues with carb causing your start issues including rich mixture.
What leads you to vapor lock?
What leads you to vapor lock?
Heat shield as mentioned, there is also spacers for some applications for this problem to lift the carb up a bit to reduce the heat-soak.
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Good points already yet Funflyers insulator gasket under the carb should solve it.
Summit has a plate that goes under the carburetor to eliminate vapor lock. 71 Chevelle had this problem called them and sent plate no more problems. Seems like height of plate was different. I am sure other changes we didn't see. Cheap fix
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Originally Posted by madRiver
While it may be vapor lock it could be a plethora of other issues with carb causing your start issues including rich mixture.
What leads you to vapor lock?
Won't restart when hot
While it may be vapor lock it could be a plethora of other issues with carb causing your start issues including rich mixture.
What leads you to vapor lock?
Won't restart when hot
If your intake manifold has an exhaust crossover, that is the first thing that needs to go. Easy way is to use one of the FelPro intake manifold gasket kits that includes stainless restrictors and block-offs for the crossover. I've watched water boil off of the intake manifold where the crossover comes through.
Phenolic carb spacer or the "thick" carb gasket (if Quadrajet) is the next thing to do.
Your carb engine almost certainly does not have a fuel cooler, so I wouldn't worry about that.
Unless you have some serious restriction in your fuel lines, I wouldn't worry about that or insulation. Your engine doesn't have bare exhaust manifolds glowing with exhaust heat. You also don't have an engine bay baking with 200° heat after shutdown like a car.
Phenolic carb spacer or the "thick" carb gasket (if Quadrajet) is the next thing to do.
Your carb engine almost certainly does not have a fuel cooler, so I wouldn't worry about that.
Unless you have some serious restriction in your fuel lines, I wouldn't worry about that or insulation. Your engine doesn't have bare exhaust manifolds glowing with exhaust heat. You also don't have an engine bay baking with 200° heat after shutdown like a car.
Boiling fuel out of the carb is not vapor lock. That is heat soaking and boiling fuel ...
Vapor lock is vaporizing the fuel in the supply line from the tank. 1940's and 50's Chevy's were famous for this. Pulling a hill on a hot day the exhaust heat would warm the supply line until the partial vacuum between the tank (rear) and pump (front, engine) would allow the fuel to change state to vapor. Then no fuel to the engine. Pull over and let it cool down and hope you had enough battery to reprime the pump when it was cool.
Best fix, install electric fuel pump to push the fuel, instead of sucking it. Shade tree fix, insulate the line. Hot rod fix, dual exhaust moved away from fuel line
Vapor lock is vaporizing the fuel in the supply line from the tank. 1940's and 50's Chevy's were famous for this. Pulling a hill on a hot day the exhaust heat would warm the supply line until the partial vacuum between the tank (rear) and pump (front, engine) would allow the fuel to change state to vapor. Then no fuel to the engine. Pull over and let it cool down and hope you had enough battery to reprime the pump when it was cool.
Best fix, install electric fuel pump to push the fuel, instead of sucking it. Shade tree fix, insulate the line. Hot rod fix, dual exhaust moved away from fuel line
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