Newly tuned Merc 225-HP 2-stroke runs rough, stalls

Frank O

Seaman
Joined
Nov 2, 2006
Messages
62
Earlier this month I took my 21' center console boat with 1994 Mercury 225-HP 2-stroke outboard in for annual service. When I got it back in the water to move it to its slip, it seemed to run fine at harbor speeds. Then it sat in its slip for a couple of weeks during bad weather.

This morning we took it out. Seemed to run normally getting out of the harbor and to our first fishing site. We then trolled for 10 minutes or so at 5-6 knots. At the end of this time it hesitated and died. It wouldn't start up with the throttle in the normal neutral position. If I pushed in the button on the side of the throttle and advanced it so that it was set to high throttle but out of gear, it would start up. When it was time to head back to the harbor, it seemed to hesitate when I moved the throttle up. At fast speed it ran, but made sounds every few seconds like a misfiring cylinder. At harbor speeds it stalled a couple of times, and I had to do the thing about taking it out of gear and advancing the throttle to get it to start.

The outboard shop that did the annual service on it is currently closed for the holidays. Any suggestions on what to investigate? I've usually used the procedure with advancing the throttle out of gear when the engine's been flooded. Would these symptoms be consistent with a stuck needle in one of the carburetors? One side note -- by our Southern California standards it's been very cold lately (30's Fahrenheit when we get to the boat).
 

mikeneal

Senior Chief Petty Officer
Joined
Jan 28, 2004
Messages
710
Re: Newly tuned Merc 225-HP 2-stroke runs rough, stalls

I might suggest water in the fuel. Check water sep. filter as a start.
 

Frank O

Seaman
Joined
Nov 2, 2006
Messages
62
Re: Newly tuned Merc 225-HP 2-stroke runs rough, stalls

Thanks. Since I only have limited opportunities to work on my boat (it's not stored at home), if it looks like water in the fuel isn't the problem, would there be a next line of investigation to try?
 
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