Best way of fixing vapor locked carb?

I like the comradery,the way HAMB members step up!

 

The problem is more than likely todays fuel that boils at a much lower temp than 10 years ago or so. I recently went through this on my dad's '58 Chevy with a 348. I tried all the usual remedies like carb insulators, insulating the fuel line, moving the fuel line etc. I also tried an electric fuel pump. Nothing worked. The problem was that the fuel would boil in the carbs when you were sitting still in traffic on a hot day. I read a thread on the Hamb about vapor lock, and someone suggested running a return line back to the tank using an early 80's Jeep fuel filter. It would allow a constant supply of cool fuel to enter the carbs. It worked great, and I have fixed several other cars using the same Jeep fuel filter.

 

#33;
" I read a thread on the Hamb about vapor lock and someone suggested running a return line back to the tank using an early 80's Jeep fuel filter. It would allow a constant supply of cool fuel to enter the carbs. "

Is that a can type filter with a small 3'rd nipple out the top side?
Tom S.

 

can i reply with a question?are some cars more likely to have this problem more than others.growing up i remember my dads 260z doing this all the time.i have a big motor in a little truck with no clearance never had any problems

 

I usually install a filter up front that has the return port back to the tank. I just secure a fitting in the filler tube to accommodate this return. When the carb needle is closed, fuel will flow back to the tank and keep things moving. Never has failed me yet.

 

Yes, that is the type.

 

Would you please post a picture from the filter to the tank??
I have the stock tank behind the seat and I would like to take a shot at this if my problem persists.
Thank you

 

I always use an electric fuel pump, as close to the tank as possible. A fuel pump can push fuel so much easier, than it can pull. I haven't ever had any problems, since.

 

If I mount a diaghram pump two feet above floor level and pipe gasoline from a tank on the floor up six feet and into the bottom of a five gallon bucket, I would venture to say that I could light that fuel in the bucket on fire and still pump fuel into faster than it could burn off. So, explain this vapor lock and boiling in the float bowls again.

 

Bump - what was the fix? Thanks

 

yesterday my car spittered and sputtered and engine died. I pumped the pedal and it fires right up but dies real quick. I looked at my see thur filter and it was alomost empty. I turned the key on and wiggled the line with the filter and the filter refilled itself and engine started right up and died. filter was empty again. I called for a flat bed waited an hour by the time I got home 1:30 min had passed and when we took car off the flatbed it fired right up. we stood there with engine running for well over 50 min and when temp got to 195 it started running as if it was running out of gas. pushing throttle pedal made it stutter worse. no fuel? a pressure gauge indicates pressure being 10lbs before regulator and 4-5psi at the carbs after engine has cooled off for an hour in my underground parking (which is cold on the hottest of days). I suspect the fuel is so full of junk that it boils off to quickly inside the line causing this vapor lock situation. we disconnected the fuel line at the fuel log and with the key on pump humming away it would not push fuel thru an open line. squeeze the rubber line a few times a fuel pumped out of the line in a Big way! the pump is working. however just to be sure...I installed a brand new pump and within an hour it did the exact same thing. engine would start and die after 30 sec of running. the distributor is new the coil is new Loads of spark from MSD ,the lines and pump are new even the carbs and intake are new.nothing is touching anything hot. no lines are blocked. this is heat /fuel related carb spacers helped a wee bit but not enough to cure this problem. the pump is located real close to the tank and no where near the exhaust. after chatting with an old Mechanic that's in his 90s this is what he said. " cars that are as old as yours need to have leaded fuel to run correctly. add lead additive to your tank " and he said I will find the fuel will be cooler and not have a vapor lock problem. I will try this altho Im not 100 percent this is the solution. but if there is some 10 dollar bottle additive that cure this problem will stock up on it . has anyone ever heard of lead additive bringing down the fuel temp? or stopping vapor lock?

 

I've heard tell of a pint or two of Kerosene in a tank of fuel helps for this, but I dunno. Maybe marvels would work too, if this is the case.

 

Also consider...

A) Fuel tank not venting properly.

2) Plugged in-tank fuel strainer on the end of the pick-up tube.

 

"73 Chev PU, 383 engine. I was travelling through Nevada and had fuel supply failure right after filling up the tank. Struggled to get to Tonapah even though it was a cool day. Figured it was bad gas so purchased a 2" aluminum filter (they didn't have Quadrajet carb filter) and installed in the line. Had problems on and off with what appeared to be vapor lock for next two years. Moved filter to before pump and installed electric booster. Still problems. Thought about it and realized all my problems started with the filter installation. Duh! Took it off and no more problems.

 

Actually a carb cannot "vaporlock" the terminology comes from the fact that a fuel pump cannot pump vapor.

What normally happens with the new fuel is that it evaporates while you are setting. 2 simple cures are electric pump near the tank to push fresh fuel into the carb before you try to start it or isolate the fuel system including the carb from the heat.

 

Here is what cured my vapor lock problems

https://49fordcoupe.smugmug.com/Fighting-Vapor-Lock/

 

I was having a similar problem and could be driving and the car felt like it was literately running out of gas,there would be no gas in the filter,I replaced the pump & the filter while I was at it.

I also rebuilt the carburetor.several weeks went by and the problem reared it's head again and left me sitting on the side of the road,I called a rollback and had the car taken to my pal Earls Garage and a few hours latter i got a call to come get my sedan.

When I arrived he said the car is fixed and it was going to cost me 50 cent.

I said "HUH?"

He got it on the rack and noticed the small hose between the pickup and the fuel line had a split in it,after we talked about it I reakized that hose was more than 20 years old.

I spent about 200 bucks chasing a 50 cent problem. but I haven't had a problem since then. HRP