Firestone & Scotty with Tillotson Carbs and Similar Problems

[twocyclemania]

I'm trying to resurrect two motors with similar fuel problems. I think they are conspiring against me. One is 1950 Fiirestone 5.0 (two cylinder) and the other is a 1961 Scotty 3.6 (one cylinder). Both have fuel tanks on top. Both tanks have been cleaned, in-line fuel filters added and the flow of fuel is fine. Both also have Tillotson carbs; the Firestone with a metal float (hinge type) and the Scotty with a cork float (no hinge) with a visible pin (out the top of the carburetor bowl cover). When the pin is extended out the top approx 1/4 inch it tells you the bowl is full. Both have had the carburetors cleaned and both motors run great but only for a minute or less. Both are not getting a continuous and adequate supply of fuel. Let them sit or tilt the motors or even squeeze the fuel lines and fuel is restored; they start, run and then run out of fuel. I've even applied pressure to the fuel tank at the fill hole. I need help from someone who's been there with these motors. Why are they starving for fuel? Do they hate me that much?

[tmcalavy]

Sounds like a float or vent problem...make sure the vent hole on the gas caps are open...you are opening the gas cap vent right? Could also be the filter inside the fuel tanks...they get cruddy and plugged with debris, etc...easily replaced. Check both floats...remove them and see if they float okay over the course of a day or two in coffee can with some gas in it. You can solder up small holes, seam breaks in metal floats and recoat old cork floats with superglue to make them fuel proof...you can also make a new cork float if yours is toast using simple tools found in most shops.

[twocyclemania]

Thanks Captain tmcalavy: I did try running them with the gas caps off and no difference. I should have mentioned that. There are no filters inside the tanks. I did add in-line filters from the tank to the carbs along with new fuel lines. The flow right up to the carb is good on both. I'm going to take your advice and remove both floats and check out on how they float over a couple days. The one oddball thing is the one with the cork float has a visible rod (the inlet valve) that rises up through the top cover of the bowl. When the bowl is full the rod extends approx 1/4 inch. If I don't touch the motor the rod will stay in the full position forever indicating it has a fuel and also that the cork should be good. But start it and that fuel is gone in 30 seconds, the rod/valve/cork float goes down and at that point fuel should be let into the bowl but it doesn't happen. I thought maybe the cork was slipping on rod so I put some epoxy on the cork/rod to make sure. Still does the same thing. I'll take em apart and give em another look. I'll let you know.

[F_R]

Try it without those in-line filters just for kicks. You can always put them back.