Carb won't prime

[Train]

I replaced the carb on a small push mower. The old one was full of water and rust, tried just cleaning it but that didn't work, so the new carb was put on. I can't seem to get it to prime. If is squirt a little gas into the cylinder, she starts right away and runs fine. Turn it off for a short while and it starts again. But if she's been sitting for several hours I can't get it to start by simply priming it with the bulb. Have to go back to gas straight into the cylinder. Any ideas? The replacement carb is brand new by the way.

 

[cpurvis]

I replaced the carb on a small push mower. The old one was full of water and rust, tried just cleaning it but that didn't work, so the new carb was put on. I can't seem to get it to prime. If is squirt a little gas into the cylinder, she starts right away and runs fine. Turn it off for a short while and it starts again. But if she's been sitting for several hours I can't get it to start by simply priming it with the bulb. Have to go back to gas straight into the cylinder. Any ideas? The replacement carb is brand new by the way.

Can you take the new carb back and ask for another one? You shouldn't have to repair a brand new carburetor.

If that's not possible, maybe you'll get lucky and just need to replace the primer bulb itself. Look for a crack in it.

If that's not it, it becomes a matter of tracing the passages for where this priming gas is supposed to go. Some of those primer bulbs act as the vent for the float chamber. When you use it, you're covering up the actual vent hole in the center of the bulb and pressurizing the float chamber, pushing gas through the jets. You might have to take the carb off and leave it connected to the gas tank to see if it's actually doing that.

 

[bertsmobile1]

If you want help specific to your mower we need to know what engine you have otherwise it will just be generic info like you have already gotten

 

[Train]

This is the carb that's on there. It's a little Murray push mower. No decals on the motor anymore but looks like the typical 3 1/2 to 5 horse. What is that red tube for? If it has to do with the primer, I'm wondering if the end isn't maybe pushed tight against the air filter.

 

[Big- ed]

the red tube is the vent tube most of the time when a carb wont prime its due to bowl gasket not sealing so the fuel will actually push up and out also check the float setting on the new carb

 

[Train]

I'll check the bowl gasket for proper seal. If it was a float problem, wouldn't that affect the way the mower ran? Once I get it started, it runs perfect.

 

[primerbulb120]

From the carb picture I see it's a Tecumseh engine. If you ask me, the primer bulbs on those engines are a horrible design. You have to push them hard and push them all the way in to get the best results. If you post a picture of the actual engine, I might be able to help you find its model number.

I have had the same problem on multiple Tecumseh engines. I'm thinking about putting a choke on mine instead of the primer bulb.