Yamaha f20 2008 carb question

[Reefy]

Hi all. I have a 2008 f20 yamaha. Runs bad caughing and spitting. Ive cleaned the carb inside and out. Fresh gas as well.

When I remove the prime start solinoid (on the top of the carb) and place my finger over the hole where the auto plunger needle goes up and down, the engine runs perfect! Take my finger off and stalls.

As soon as I install the solinoid runs bad. The needle moves up when hot down when cold. Seams to function right.

Anyone had similar issues or suggestions?
Thanks!

 

[Reefy]

Actually the needle moves up when cold and down when hot....

 

[Reefy]

Haha I'm talking to myself I don't care I found the cause!

I bypased the fuel pump by taking the line off the fuel pump and putting it directly to the carb. Requires me to pump the ball while the motor is running but now it runs like a top. Must be a cracked diaphragm in the pump which was causing all the smoking as well.

Bad news is one of the screws was stripped....

I guess somehow removing the screw replacing the pump is my next step.

 

[ReelSlim]

Good that you figured it out. Sometimes when you post you will get all kinds of responses and other times you can hear crickets in the background...lol I really think it is topic related sometimes or just timing with when it's posted and who happens to be on-line checking out the forum.

 

[Reefy]

Not out of the woods yet. The stuck screw could cause me big problems...

 

[ryanb]

It's great you posted the outcome... Even if you figured it out on your own. Someone else will find this thread some day when they have the same problem.

 

[Clint r]

If it’s the screw head that’s stripped out, you can sometimes use a new sharp philips head bit and lightly tap it with a hammer to clean up the screw head enough to get a good bite with a screwdriver. First choice after that would be a small hand held impact driver(not the air kind) Or you could use a small wrench on the bit and tap at the same time and it just might come out. I’ve used both methods with some success: good luck however you go about it.

Last resort would be to file flat spots on opposing sides of the offending screw head and try and get a pair of vise grips on it. I’ve used this option a few times too. Drawback is, once you get to this point the head of your screw is nearly done for.

 

[Reefy]

It turns out the screw that was stripped was only to hold the pump housing together. It cracked in half and I was able to open up the pump. I didn't notice any holes or leaking from the diaphragm, but rubber seemed a little weathered/cruddy.

A new fuel pump seems fairly cheap online under fifty bucks. We'll have to see what a dealer will quote me today...

Weird that I didn't see any holes or cracks I fully expected it!

The screws holding the pump to the engine block were totally fine so a new pump will bolt right on.

And it was 100% this place where I read about fuel pumps going and symptoms. Lots of good information here thanks everyone!