Any ideas?

[Dan Thiem]

I have a 1984 Johnson 25 horse. Faithful service for many years. Yesterday it decided to be wierd on me. I could ony keep it running if I kept the choke butterfly 3/4 closed. Almost all the way closed sometime. I take the choke off and it just idles down and kills. The ball is hard and the vent caps is loose. It's worked fine all year. Fresh gas too by the way.

Anybody have an idea where to check?

[Valv]

Time to do a carb job Dan. If it runs with choke only the needles are plugged or has problems with gas flow in the carb......Try to take carb/s apart and clean it/them VERY VERY well.

If you can try to find a good inline filter, it will help a lot with the "dirt" that you find in gas tanks.

[Keith_MN]

Dan,

You may not have to go as far as actually tearing the carb off. I would start by taking the gas bowl off first (which you would do to get to the carb anyway), especially if the motor was running good prior to this. Clean out the bowl and make sure the float and needle are clean.

I have a mid-70's 9.8 hp Mercury that pulls this on me occasionally. The needle on the float sticks in place in the closed (ie up) position which prevents gas from getting into the bowl. Often times I can get it to come loose (ie unstick) just by tapping the bowl lightly with a hammer. But if you haven't taken the bowl off in a long time its probably due.

Then run some carb cleaner thru it with the gas. I personally am a big believer in Seafoam.

Good luck.

[Guest]

Pull the carb off and clean the needle valves and jets.. make sure every little hole is clear.

It will run fine after if you get everything out.

A carb kit is usually inexpensive and will take care of plugged jet issues also.

[Dan Thiem]

Excellent advice guys! Thank you so much.

Another reason why this site is the best!

[kato811]

try tightening the carb bolts it might be loose

[delmuts]

after you get it cleaned; run seafoam all the time.( i was told to do this after having the carbs cleaned at a shop) it will help prevent this happening again.