Need help fast!

[will941s]

'98 Merc 25 HP, 2-stroke

Took the boat out today - ran great, started great, ran for about 2 hours and everything was fine. Shut motor off and started it back up - it was hard to start and would not run idle, but when the choke is pressed it will stay running. As you push the choke and put it in gear the boat will run fine. The boat will not run if the choke is not engaged.

Motor was just serviced, carb was just cleaned, it has a water fuel separator, there are no apparent fuel leaks, and gas tank vent cap is open. Also, compression on both cylinders is 135 PSI.

Please I need help fast - any help is very much appreciated. Thanks.

 

[Really Old Guy]

Re: Need help fast!

I would look for an air leak in fuel system.

 

[will941s]

Re: Need help fast!

Going back out tomorrow to look at it again. When you give it the gas it runs great...even without the choke, it just won't idle unless the choke is engaged. If I sit there and keep milking the choke button it will idle all day long. While I am "milking" the choke I can put it in gear and take off and everything is great, then when I come off full throttle and go back to idle, if I dont keep it a little above it idle it will just die in gear. Just caught me off guard because the whole day it ran like a champ. I shut it off, restarted it, then it died, and the problem started. Got back to the ramp....and checked the compression (gauge kept in the boat) and that was great. I will update the post when I find the problem. Keep ideas coming if anyone has any.

 

[verado7]

Re: Need help fast!

give your idle mix screws a 1/4 turn to the left -sounds like they set too lean and that will give you hard to no starts and stalling at idle - if you need more go another 1/8th turn .

 

[will941s]

Re: Need help fast!

Thanks Verado, I checked the carb setting and the thing as rich as it can get. The plugs are pretty wet, pistons are wet, and it has the nice black oily residue around the prop hub. I am scared to death of a lean mixture and if I see dry plugs it gets adjusted. I even run it at 35 to 40:1 ratio just for the extra comfort. Plugs are cheap, motors are expensive. I read up on the enricher, and if I'm correct it pretty much loads the carb with gas. So when I am pressing the button and it stays running, would it be safe to assume that the "extra" gas it should be supplying is now supplying just enough to keep it running? If so then where do I start in the trouble shooting process?, other than looking for a leak.

 

[rosser1]

Re: Need help fast!

Is this the first time you been out since cleaning nad maintance job ?? if so, yep i would say too lean. Try a 1/8 turn to left to start, try that if need more then go another 1/8 always when fine tuning go by 1/8ths. Mine was ran fine in driveway and not idled enough for when in water. give it trottle it would die. so i adjusted carbs on water and worked out great. So try adjusting !!

 

[will941s]

Re: Need help fast!

This was the 9th time since the service the boat was out. All the other times there were no problems at all, just half way through this trip. Im going to recheck all the lines and take it to the boat ramp and tinker with that mixture screw a little bit. I will update when I find the problem. Thanks for the help.