Yamaha F4B Outboard Motor 4 HP..won't run with choke in...help!!!

[Alan]

I posted a week or so ago that my used motor ( A 2003 Yamaha F4B 4 HP, 4 stroke) outboard I purchased with my used alumacraft boat, would not run with the choke in. I then realized that I had not opened the vent on the gas cap for the built in gas tank. (This was my first time using the motor) So I thought this may have been the reason, and a few folks here agreed. I used the choke for the first 5 minutes or so, and then pushed the choke back in and off, and then the motor just dies! This happened today as well,(On my second trip out on the water) and this time I remembered to open the vent on the gas cap. I am really frustrated! If the choke is out, she obviously is running high RPM's, but it runs and gets me across the lake. But I really don't want to wreck my motor by doing this.

Does anyone have any thoughts on what may be causing this? Are there some things I can do to test it and do the process of elimination for what's causing it? I plan on bringing it into Erickson Marine in Hastings to get it looked at if I can't figure it out, but money is a little tight right now, and If I can fix it myself, I would prefer that route.

So, any help, advice or direction from all you experienced boaters out there, I sure would appreciate. I wanted to ask here before I called the shop, because this seems to be the place to come for help or advice on problems with fishing or boating...

Thank you all!

[eurolarva]

I dont know your motor however when running with a choke that means your motor is running lean. This could be from different reasons however the most common is a dirty carb. When you forget to open the vent you put excessive force on the rubber diaphram in the fuel pump and you may have ruptured that however a motor does not usually run at high rpm when the fuel pump is blown. If it were me I would take the carb apart and clean and rebuild it. If that does nothing to fix the problem start working back to the fuel pump, fuel filter and the primer bulb. If your carb has a mixture adjustment I would turn it maybe a 1/4 turn counter clockwise first and see if that helps.

[Alan]

Just talked to the dealer. They told me $200.00 to $300.00 to fix it up, they say it sounds like the carb may be gummed up. Or a bottle of ring free to try first. Anyone ever use this stuff as a shock treatment? Should I try it?

[marine_man]

Ring free is more of a carbon cleaner for the combustion chamber more so than a carb cleaner.

marine_man