(800) 853-2651
SHOP NOW

Vapor lock

H

HWess

Member
I have a 1/4 inch OD copper gas line gravity feed from the tank to the carb on a car. Occasionally experience symptoms of vapor lock. Would a larger,3/16 OD, be less likely or more likely to cause vapor lock?
 
Senior moment. I meant to say 5/16. Also I forgot to say it must go near (2 inch) the exaust pipe.
 

Clip clothespins to line to dissapate heat. Worked on a 1955 Buick, for a while. Finally had to get a new fuel pump. Wrapping line in aluminum foil to reflect heat might work, don't remember if I tried that.

KEH
 
I have thought about what you said and I don't think you can get vapor lock with gravity flow. If you do get vapor the head pressure will push fuel down pushing the vapor with it. the vapor will end up in the carb. and vent out there. I don't believe that all the fuel coming down could turn to vapor starving your carb of liquid fuel. Now with a fuel pump that is different. The fuel pump can't pump vapor. That is when fuel flow stops. the vapor gets to the pump and that is the end of pumping. What kind of car are you talking about where the fuel is higher than the carb. Unless it is something homemade or cobbled up, it doesn't need or have a fuel pump.
 
Reroute it away from the exhaust pipe that is to close for comfort. Or put a heat shield between them to dissipate the heat.
Walt
 
fuel pumps were installed to help prevent vapor lock. the higher the pressure on the fuel, the hotter the fuel has to get to boil. Same as a radiator cap. so fuel pumps and careful routing of the fuel lines pretty much eliminated vapor locking.
 
You need a less volatile fuel. Todays vehicles have high pressure fuel pumps so fuel from the refinery is more volatile than in the past. Adding a can of 2 cycle oil at a mix of 50/1 should fix your problem and also give that old engine some top cylinder lube.
 
Yes, I knew some cars had gravity flow. However I never knew a gravity flow system had a fuel pump. The 2 you mentioned for example did not have a fuel pump. You didn't say if your case had one. I'll bet it doesn't because it doesn't need one. I think you will find your problem something other than vapor lock. As I said, Mother Nature is making your fuel go down hill to the carb.
 
sotxbill, I disagree fuel pumps were installed to prevent vapor lock. They were installed because fuel tanks were placed below the carb. The 32 Ford for example put fuel down low and had to have a fuel pump to get fuel to carb. That is when vapor lock problems started with Ford. Sooo fuel pumps were the cause of vapor lock, not the cure for vapor lock. You are correct proper routing of fuel line can help. What has eliminated vapor lock is the fuel pump being put in the tank or way back where there will be no vapor. The fuel pump will then pump and any vapor that may happen near the engine is pushed on by the pump just as gravity (head pressure)pushes when the fuel is higher than carb. Did you ever see a car, tractor,etc. with gravity fuel system and a fuel pump?
 
Nancy,

It is an arbitrary term that means, "I can't figure this thing out".

I've been turning wrenches the better part of 60 years and have yet to run into a case of ACTUAL vapor lock. It is often used just as an excuse. :>)

Allan
 
(quoted from post at 08:50:36 08/11/09) Nancy,

It is an arbitrary term that means, "I can't figure this thing out".

I've been turning wrenches the better part of 60 years and have yet to run into a case of ACTUAL vapor lock. It is often used just as an excuse. :>)

Allan
Click to expand...

Allan, I have been involved with quite a few cases of fuel vaporization problems. The most spectacular was on an 1800 international truck with a 478CID engine. On hot days when running under light to moderate loads the fuel would vaporize in the fuel line before it got to the fuel pump causing the engine to run lean. Unfortunately that engine had a very bad habit of blowing the mufflers apart when that happened. The problem was solved by installing an electric pump back on the frame and rerouting the fuel line on the outside of the frame and not using the mechanical pump on the engine.

Another one that has a less successful ending was an I-574 with a loader on it. When baling hay it would start to miss and shear the bolt in the baler flywheel. Insulating the fuel line and rerouting it away from the engine helped but the owner decided to work with it that way rather than remove the loader which he used almost daily. He should have used your solution and gotten more tractors !
 
(quoted from post at 06:55:51 08/11/09) ........ Did you ever see a car, tractor,etc. with gravity fuel system and a fuel pump?
Click to expand...

I have two of them. My IH W9 and I-2444 both have fuel pumps.
 
You must log in or register to reply here.

Similar threads

H
Propane to Gasoline
Replies
5
Views
470
Moonlite37
M
B
  • Question
Courage Pro Backfire
Replies
5
Views
517
T.R.K.
T
A
Oliver 1755 Gas
Replies
7
Views
1K
scootergmc
S
B
MH 44 Won't keep running.
Replies
19
Views
449
stevieb49829
stevieb49829
W
Addition to quick fix: Not to steal Tgrashers post;
Replies
0
Views
386
Wheat47
W
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top