Zenith 267 carburetor

I worked on a '74 dozer. with a 201 gas. With a Zenith 267 carburetor.

It ran perfect, but now it will start right up, and idle. after a couple of minutes it will die. most the time I need to pull the choke, and it'll start right up again, but will kill right away. With the choke in or out. Some times it will idle after restarting it, as long as I don't touch the gas.

I looked at the fuel filter, and it looked like it had crap in it, and little water. We had cleaned the inside of the fuel tank, last fall. It has not run since spring, when I had to rebuild the engine for him. So the water has to from condensation. It also had a fine rust in it. You can't fell it is so fine.

I then removed the filter and drained the tank, I had only put 5 gallons of gas into it. I had drained it when I was putting the engine back in. It looked clean then.

I put a new filter on it, took the carb off opened it up. It looked clean inside, but I went through it again cleaning all the ports inside, then closed it up. checked the flow, which is good, then I put another 5 gallons of new gas into it.

Does the same thing. If I remember right, I have the jet adjustments around 1 1/2 turns out each. It does get the intake cold when running. Before, and now.

any idea's.

Thanks, Pat

If it dies idling after two minutes, sounds like the flow out of the bowl exceeds the flow into the bowl and it empties in two minutes. Check EVERYTHING pertaining to the flow into the bowl. Sometimes what looks like good flow from the tank line is not enough.

Beware of blowing air into the carb fuel inlet passage. I crushed a float doing that one time.

Also, I have included a cross section of a Zenith carb but not a 221. This is off a DC. Notice the various fuel passages openings within what is circled. Every one of those openings needs to be squeaky clean which means all parts within the passage needs to be disassembled and cleaned. Remove the power jet and the long slender "tube" that screws in opposite the power jet.

I will pull the power jet and tube out again. I did not this last time. I lost count of how many times I have pulled this carb apart in the last two years. I have never had a problem running good, after I have reinstalled it before. It really is a simple carb to work on.

Side note. Back in the late 80's, early 90's. I designed & built a mold that made this carb body, for a guy that ran investment molds (lost wax), at his foundry in MN. After I had sold both my tractors that used this carb. Now mine is a diesel.

No, I would not ever blow air through a float seat, unless, I do it by mouth, or if the needle is out. But thanks for the warning.

Thanks, Pat

Always good to know more about to whom I am writing. Thanks. I am still leaning towards you have a fuel inlet flow problem.

Not sure what you are calling the filter. As you know, sediment bowls have a flat disc fine wire screen in them. Are you calling this the filter?

I have been tripped up by inline filters on gravity flow systems. I have found the gravity flow inline filter should be no finer that a moderately fine screen so that any particle of dirt/rust that passes thru this screen will likely pass thru the smallest holes in the carb system. Paper inline filters seem to need a fuel pump. Often parts people don't know the difference.

Rust in the fuel tank---I find is hard to get it all out. I resort to putting a short stand pipe (about 5/8 inch tall in the sediment bowl inlet. A 5/16 drill about a 1/2 inch deep and a short length of 1/4 ID copper tubing seems to press in nicely. If not add a little Locktite.

I learned that rust particles are about 15 times heavier that gas so any residual rust within the fuel tank tends to only slides around on the bottom of the tank during operation and does not mix much with the gas during normal sloshing. The turbulence of a power-fill nozzle is a different story but very little dirt/rust particles/rust flakes finds their way into the standpipe from the fill nozzle turbulence. The stand pipe always solved my rust problems and is standard procedure for my restoration projects.