WD-45 Vapor Lock

I have a 1950s WD-45 that keeps vapor locking after about 10 minutes of use. Very dangerous when I'm on a hill. Is there a way to stop it from happening and when it does how do I fix it?

 

Gravity feed fuel systems don't vapor lock. Sure you're not loosing spark?

Why would it help to do that, Lou?

ROFLMAO at Larry's question, not somebody else's misfortune.

Gotcha Lou,LOL.

Either your points /condensor or coil die after they warm up... and fail.. then cool down and work again... OR like Lou's crap in the tank idea... Need to clean fuel system out real good... Check for good gas flow from fuel line down at carb, drain a good quart of gas at that point and see if its full flow from when you turn the tank valve on to the time you turn it off. check for floating debree in bottom of tank that goes over the outlet in tank, such as a bee or soybean ,etc..  Possibly take carb off and clean it and check the inlet to carb and see if there is dirt over the needle valve in there.

Edited by JC(WI) - 19 Jul 2010 at 8:42pm

As a follow up to my problem.  I had the carb rebuilt on my WD45 over the winter.  The problem is that after about 10 minutes of running the engine acts like it wants to die.  if I pull the choke it dosn't die and after a minute of pulling and releasing the choke the engine starts to run normal again for another 10 minutres then starts all over again.

You might want to think about putting a Wix filter #33032 or Fram G-15 in your gas line to filter out the fine crud. I run those filterson the 190 gas...When the filter starts plugging as in tractor starts sputtering, I just slip the filter off the hoses and blow the thing out backwards and get the crap/debre out and slip it back in and go. - I have seen where guys have cut the gas line to put them in..... But I bought a nipple fitting that would go into the carb and about a foot and a half of hose and cut that in two. Then I pushed pipe nut back up the line and slipped the end of the hose over the pipe an clamped that end then slipped filter on and slipped other hose onto other end and hung the filter under the carb and connected final end of hose to hose nipple that you just put in the carb where fitting for pipe origionally was. I then ran a wire through the old fitting and wired it to carb. ---- If at anytime I desire to rehook the line back to the carb, its just matter of minutes and it will be like origional again.

The ten minute time delay is typical of a gas cap that isn't venting, a condenser that is breaking down from heat, and a coil that is breaking down from heat. Usually it takes a while for those to cool or vent. The fact that it runs while choked hints that its a fuel problem, probably low flow to the carburetor, that has been discussed on this forum many times. Among the hidden places for a fuel restriction, there is generally a fine metal screen on the inlet adapter to the carburetor that can get so plugged a tractor will only idle for a few minutes then won't start for 15 or 20 minutes. The fuel line itself can be clogged with varnish restricting fuel flow. The float or float needle can be sticking closed or nearly closed. Sometimes beating on the carburetor will temporarily shake those loose. It could easily be something floating in the gas tank from a chip of paint, to butterfly wings (the pink parts of an ear of corn), to a scrap of paper. It isn't always the same thing giving the same symptoms, because any of these can do it, or it can be a combination of several or all.

Gerald J.

Vapor lock is not possible on a gravity fed system, unless maybe the fuel line were touching the exhaust maifold. Vapor lock happens when the fuel in the fuel line boils and the pump is only able to pump the boiling vapor. That's why large, carbureted vehicles of the 70's and 80's had a return line added to the engine mounted fuel pump. This served 2 purposes, 1 provide an escape path for vaporized fuel in the line, 2 to cool the pump and lines with cooler fuel from the tank to prevent bubbles in the first place. Gravity fed systems have no pump and always have the weight of the fuel on the fuel system except for maybe extreme angles. Any bubbles will quickly flow through an open float valve. It's just not possible with the fuel lines out in the open to get them hot enough to vaporize the fuel to the point you get no liquid to the carb.

feedback is always appreciated! let us know what it was. If you do crap in the tank and it works, don't forget I'm the one that suggested it!

That sounds like the gas cap isn't venting.

It started running after 30 seconds because... as he stood there, the tank was warming.  With a slight negative pressure in the tank, the fuel's vaporization point goes lower, so gasoline is actually vaporizing.  This takes the place of venting, but not right away... once fuel starts vaporizing enough, you'll get a little flow out the hose.

One thing I always do with a fuel system blockage... is use a little air gun at just 10psi or so, remove the gascap, and push some air BACKWARDS through the whole thing.  I watch the tank to see what crap comes out...  then I formulate a cleanup plan, which usually involves a white cotton T-shirt, a big funnel, and a secondary fuel tank...