Yamaha 25 4stroke starts then dies.

[SnookHunter]

I have a 2004 Yamaha 4stroke that won't stay running on its own.

I last used the boat about 6 weeks ago. I tried to start it and it wouldn't start at all. I figured carbs had trash in them. It did. Looked like someone threw up in there. Cleaned them up and then I soaked the carb for about 6 hours in carb cleaner. Bought a rebuild kit as well as a fuel pump just for piece of mind. I also replaced the fuel lines, gas tank, spark plugs, primer bulb,fuel filter, and anti siphon valve. Pumped the primer bulb until it was hard. Ok, try to start it for about 30 seconds and nothing. Check the container with the fuel filter and its dry. Put some gas in there and it turned over very briefly. But never fully started running. There is a black tube with a screen over it above the carb that sucks air in and when I put my hand over it, it fired up. So I quickly grabbed the throttle and reved it up and it died. Ok so I repeat the process and put my hand over the tube and it starts again this time I started pumping the primer bulb and it stayed running and reved up fine. But when you stop pumping the primer bulb it dies in about 30 seconds. It will run fine as long as you pump the bulb. But it will not start on its own unless I put my hand over that black tube.

Any ideas? I should also mention my drain screw broke off in the carb when I tried to remove because it was corroded, but I sealed it with jbweld. Could that be my problem or more trash in the carb? Also are attwood products any good? That's was the gas tank is and it seems like a cheap pos.

Thanks for any help anyone could offer.

 

[rodbolt]

Re: Yamaha 25 4stroke starts then dies.

more trash in the carb and you possibly installed the fuel pump incorrectly or its sucking air.
by placing your hand over the air intake you force it rich bypassing all the carb running circuits.

 

[SnookHunter]

Re: Yamaha 25 4stroke starts then dies.

Thanks for the reply. I don't think I have the fuel pump stalled correctly. It came pre assembled from the factory and I would assume there is only one way to installed it?

Do you think letting the carb soak for 24 hours or so will help get rid of any trash that might be in the carb?

 

[eng241]

Re: Yamaha 25 4stroke starts then dies.

Have had very little luck with carb cleaner. You need to find someone who has an utrasonic cleaner with heat. Those carbs will bee spotless after they are done and you will not have any problems with them.

 

[SnookHunter]

Re: Yamaha 25 4stroke starts then dies.

Soaked the carb overnight in carb cleaner. And then reinstalled everything. I primed the bulb until it was hard and it fired up on its own after 10 seconds of cranking and then died again. It idled fine for about 30 seconds and the nothing. After the intial start up the motor would not start again unless I put my hand over the intake. Wont stay running unless I prime the bulb. I noticed the container that encloses my fuel filter barely had any gas in it. That means my problem is from the carb back correct?

Also nobody answered my question about the drain screw. The drain screw broke off from corrosion when I tried to take it off. I sealed it with jbweld. Could the missing drain screw be my problem?