Vapor lock

B

Buford Adamson

Junior Member
Helped a friend with his 23 Roadster yesterday. The T was running very rough, after some trouble shooting, installed a new timer and all was great. Took it for a test drive and after a couple miles it died. Let it set for a few minutes and it started and ran just fine. Pulled into the driveway and it died again. Again let it set a few minutes and the car ran fine. We are thinking vapor lock. What are the thoughts out there on the Ford Barn.
 
The fuel is pressurized because the tank is higher than the carb. What you have are the classic symptoms of rust in the fuel. Take a container, like a large plastic drink cup or cut the top off an oil bottle. Use the container to collect the fuel when you open the drain at the bottom of the carb. You should get a nice, steady stream of fuel. You will probably get a lot of brown sand (rust) when you drain, and the fuel flow will probably stop completely after less than a cup has been drained. Long term solution is a new fuel tank.

Ron Dupree
 
vapor lock is impossible with a gravity flow fuel system, Ron has told you what the problem is, trash in the tank plugging the fuel filter or the needle and seat, remove the tank, flush it out you can put a small piece of chain in the tank and shake it around to break up the rust, them put in a can or tank sealer to lock the rust in place, if your not worried about originalty install a large filter befor the tank, a visable one if possibe to check on the rust being caught, use a filter that is easily cleaned
 
Check the vent hole in the gas tank cap, some repros do not have one or it could have become blocked. Without one the gas will flow for a while then slow to where it gives trouble.
 
I will have to disagree with the statements that a model T does not get Vapor locks. I have a 1910 Mother-In-Law roadster equiped with an NH carburetor and it did get vapor locks. When driven on a hot Texas day with less than a half a tank of fuel it would start to run very rough. If the tank was almost full it did not have a problem.
After close examination of the fuel system I found that the previous owner had run the fuel line very close to the exhaust pipe for a distance of one foot.
There was enough lenght in the fuel line to reroute it to the frame an to the carburetor, staying well away from the exhaust.
The problem was solved and I did not have to have the tank almost full all the time.
THAT WAS VAPOR LOCK
have fun with those T's
 
I would agree with Willie on vapor lock. Keeping the fuel line away from the exhaust pipe is wise & if you route it so it is always running down hill to the carb it is unlikely to vapor lock.
 
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