Rosiesdad Posted March 17, 2013 Share Posted March 17, 2013 I was hoping for something practical. Lol. Don't see myself cruising the marina looking for gas! Latest is... I ran a rubber line from under the car straight to the carb. With a 9psi pump regulated down to 4psi then up to a small fuel filter next to the carb. Now I can restart after a hot shutdown but I see NO fuel remaining in the filter just a trickle in the bottom. On the highway I hoped to see it fill up and displace the vapor but found a high speed starvation issue instead. Next attempt appears to be a recirculation of fuel to the tank. Maybe that will allow the vapor to flush out of the line! Link to comment Share on other sites More sharing options...
Peter J.Heizmann Posted March 17, 2013 Share Posted March 17, 2013 Hello, Phil.Vapor lock has been an age old topic on this forum. A popular check that has come up often is looking at how close gas lines, etc., are to heat sources such as the engine block and exhaust manifolds.If you do a "Forum Search" above in the header block you can read many past posts on vapor lock. This one is a good example: http://forums.aaca.org/f120/can-boiling-point-gas-raised-289338.htmlRegards,Peter J. Link to comment Share on other sites More sharing options...
Rusty_OToole Posted March 18, 2013 Share Posted March 18, 2013 (edited) Vapor lock seems to be more prevalent since fuel injection became universal on new cars. Their fuel system is under pressure so vapor lock is not a problem.There is no reason today for oil companies to make fuel that resists vapor lock.Some have found relief by adding 10% of diesel, kerosene or stove oil to the gas to make it less volatile. Not recommended on high compression engines. Edited March 20, 2013 by Rusty_OToole (see edit history) Link to comment Share on other sites More sharing options...
Friartuck Posted March 19, 2013 Share Posted March 19, 2013 Phil,The 4 psi to the filter/carb sounds low for a pressurized fuel system. Anyway to increase that to say 6-7 psi?? This would address the high speed starvation problem. Perhaps a special bent fuel line (clad in a woven insulating material) from the carb, around the engine (staying away from heat sources) to under the car, where you can put the filter and pick up the fuel line to the pump Link to comment Share on other sites More sharing options...
rons49 Posted March 19, 2013 Share Posted March 19, 2013 Rosie, I doubt you are getting vapor lock this time of year in SF. Fuel starvation, yes. What type of electric pump are you running? I presume you have NO mechanical pump??? If you are using a solenoid pump, that is, Airtex type that looks like a brass filter, I had no luck in maintaining fuel pressure at the carbs in my Hudson. Airtex claims 5-8 psi and more than 30gph... forget it. I checked two EP-11s and the psi was below 3.5 at carbs with the pump at the gas tank, BUT a full 6 psi at the outlet at the pump itself. Not enough for big Buick straight eight or a Twin H 308. IMO,They are fine as a helper for a mechanical pump or priming. The good pumps are the Carter Rotary Vanes. I don't like Electric only. Unsafe unless "roll over shutoffs", an so on , are added. Ron Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted March 19, 2013 Share Posted March 19, 2013 Phil, do you have a pressure gauge in the gas line at the carb? PERHAPS INSTALL A GAUGE INSIDE THE CAR WITH A SENDER AT THE CARB INLET, THEN GO FOR A DRIVE. {Sorry, hit the cap lock} Then the actual pressure under load can be observed. Ben Link to comment Share on other sites More sharing options...
Rusty_OToole Posted March 20, 2013 Share Posted March 20, 2013 4 psi is high for a carburetor system. 6 or 7 would be too high. If it is that high you should have a regulator on the carb to prevent flooding. 2PSI at the carb is plenty. Link to comment Share on other sites More sharing options...
Rosiesdad Posted March 20, 2013 Author Share Posted March 20, 2013 (edited) Thanks all. Lots of good info here. I am bypassing the mechanical pump for now. Once I get get a handle on this problem I would prefer to add the original bits back. I have installed the Airtex E8011 electric pump (9psi) and run it straight to the Carter WCD carb. I am not seeing any leakage around the carb or having any flooding that I can determine. (9 psi appears to work OK although I have not checked the actual pressure). Ron49 suggests It may deliver much less so I will need to rig up a gauge and check. Currently I have a regulator set to 4psi (Max is 5) but had some lean surge on the freeway when hot. I will set it up to 5psi and try kerosene or diesel addition to see the effect. Phil Edited March 20, 2013 by Rosiesdad (see edit history) Link to comment Share on other sites More sharing options...
rons49 Posted March 20, 2013 Share Posted March 20, 2013 (edited) Phil, Don't add anything to the fuel at first. If two factors are added, ie, Psi & kerosene, you won't be sure which solved the issue. Fuel today is lighter, ie , vaporizes faster. No way 2-3 Psi will cover drivability issues in big engines, especially with oxygenated winter gas. Bump it to 5 psi, then let it idle. That's when it will flood if it is going to. If it doesn't flood leave it. Say, why does your pressure gauge only go to 5psi? Are you using those horrific dial in type? They are not accurate and have a good chance of leaking. Edited March 20, 2013 by rons49 (see edit history) Link to comment Share on other sites More sharing options...
Rosiesdad Posted March 22, 2013 Author Share Posted March 22, 2013 Say, why does your pressure gauge only go to 5psi? Are you using those horrific dial in type? They are not accurate and have a good chance of leaking.Ron,I am runnjng a pressure regulator that goes to a max or 5psi. I will probably take it out since the engine wasn't flooding at idle. It's really strange that last year I had no problem and the filter bowl was always nearly full of gas. It looks like the heat riser valve is still jammed closed so maybe all the refineries around here boosted the ethanol content a bunch this year.Phil Link to comment Share on other sites More sharing options...
sambarn Posted March 22, 2013 Share Posted March 22, 2013 This sounds so similar to my '61 cadillac problems a couple of years ago. I did everything you have and it turned out that there was a cracked rubber line that joined the two piece fuel line above the rear axle. when that four inch piece was replaced and the mechanical fuel pump reconnected... problem solved. It was frustrating and I have a pile of fuel pump parts left over but runs like a champ now. the cracks were allow the tube to suck air but they didn't leak gas out. this created fuel starvation issues. Link to comment Share on other sites More sharing options...
Rosiesdad Posted May 5, 2013 Author Share Posted May 5, 2013 The story continues.... At last fill up I am seeing a gas leak from the top of the gas tank area. Not sure if the pick up tube is leaking or what type of connection is on top of the tank (If any). I checked the fitting I can see and the leak is not coming from there. I guess I will drain and remove the tank to see whats leaking up there. Link to comment Share on other sites More sharing options...
Ben Bruce aka First Born Posted May 6, 2013 Share Posted May 6, 2013 The story continues.... At last fill up I am seeing a gas leak from the top of the gas tank area. Not sure if the pick up tube is leaking or what type of connection is on top of the tank (If any). I checked the fitting I can see and the leak is not coming from there. I guess I will drain and remove the tank to see whats leaking up there. I KNOW! I KNOW! It is the sending unit gasket, if my guess is right. Ask how I know. Ben Link to comment Share on other sites More sharing options...
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