93 yamaha 40 hp runs only when choke is pulled out push it in it dies

Steve

• 696 Answers
• Posted on May 23, 2011

SOURCE: engine runs for about 10 minutes then cuts out and

Hi!

It sounds to me as if the motor is attempting to eat its own exhaust.

An easy way to check is to remove the motor cover and start it. USE CAUTION HERE! If the motor runs normally with the cover removed, you can be sure there's an exhaust leak. Our motor had the smallest bit of corrosion where the exhaust coupling bolted to the block and was leaking. It was fairly difficult to spot, but we finally found the problem.

Hope this helps.

SOURCE: Change question

sounds like a fuel venting problem. Loosen the cap to the gas can and see if that works.

Then (if that fixed it) you will find the vent built into the cap is sticking shut or you forgot to open it.

SOURCE: Johnson 4hp starts first pull runs 5 minutes dies will then only run with choke on

You may have left the fuel vent closed. If working, put a clear plastic fuel line between the fuel pump and the carb. Look for bubbles indicating an air leak between the tank and the carb.

On a rear occasion you can have some varnish flakes floating round the fuel bowl. But these tend to cause random problems than the "about 5 min" problems you are having.