se thermal valve

I have a 2003 bf 20 hp it wasn't used for a few years and when I wanted to use i out fresh gas and wouldn't start so i cleaned it and would run but not idle. I went through the carberator again same results. Then i found out about the se thermal valve controls the idle and can't i can't much information,or any part number. I would any suggest. jar001

The se valve controls the starting of the engine. It allows more fuel and oxygen into the cylinders. As it heats up, it's needle closes down the flow of the extra fuel, etc. Then the engine idles through its idle circuit.

If you had the carburetor apart, there is a skinny tube that goes up vertically through the carburetor to the top of the carburetor. Fuel flows up the tube, to the horizontal passage at the top of the carburetor past the idle mixture screw (which controls the fuel/air mixture, to the small pin hole at the rear top of the carburetor behind the butterfly.

If any point of this passage is plugged....no idle.

If you have the carburetor apart and the skinny tube (jet set) removed, take a can of solvent (brakekleen, wd-40 etc) with the straw that comes with the can and stick the straw up into the top of the carburetor that the jet set goes into. When you spray, there should be a good spray coming out of the hole behind the butterfly....as well as the couple of pin holes in front of the butterfly (used to transition).

If it does not spray, then you may need to back probe with small wire into the holes to unplug them. Using some compressed air with solvent sometimes helps too.

When that fails, you will have be remove the idle mixture screw, which will give you more access to that passage. It has a cap on it, to prevent misadjustment of the screw.

There are a couple of very good descriptions of how to do this posted by JGMO. The process for 8hp -20 hp are the same.

You might be able to search for one of the posts.

Do not feel bad....there are a lot of passages in that carburetor (including several in the bowl) that leave even the experienced techs scratching their heads.

Mike

It is likely NOT the se thermal valve. Mike gives good advice as always. But, if you are at all interested in doing it right and learning how these carbs work at the same time. Get the manual. Worth every penny. $39.95 at Amazon and if you have Prime....well, you know.

Here's the link....

http://www.amazon.com/Honda-Marine-...r=8-2&keywords=honda+marine+carburetor+manual

Good luck.

jgmo thanks for your help and will keep in mind