My 2005 3 cylinder Mercury 2 stroke lost power suddenly last week while pulling away from the dock. The boat dropped off plane and now only putts along at slow trolling speed. All cylinders have good compression. All cylinders gave spark. Fuel pump is jumping fuel. It seems to be running on only one or two cylinders. When running if I take the wire off of the top or bottom spark plug there is no change. If I take the wire off of the center plug, the motor dies. Any suggestions on how to fix it or who I should take it to are most appreciated.
Dennis
Got to be something simple, what it is I don't know, that's a great motor, I got a '04 40 Merc that has been run year run since new and gets used and abused heavily, on my 3rd foot now, (logs, stumps), never had carbs gone through or a wrench put on power head, good luck with yours.
I was thinking reeds too. I heard a broken read would cause fuel to spray out of the affected carb while running. I don't see that happening. You think it could still be a damaged reed? The motor has about 500 hours on it.
Try partially choking the top or bottom carbs by placing fingers across the openings. At least this will tell you if it is a carb problem. Plus disconnect the fuel lines to carbs and see if you have good flow thru all.
I'd try the fuel line first.
Thanks for the suggestion.
I choked the miss firing cylinders with my hand and got fuel running down my palm, so there is fuel there. Also the misfiring cylinders are getting spark.
Okay, I removed the old plugs. All three were wet with fuel and the gap was much larger than specified. Will get some new plugs and report back.
Dennis
Hopefully you'll see this before putting in the new plugs. Pull kill switch, wide open throttle, spin it over with the plugs out to clear excess gas out of cyls.
Excellent! I know a couple of people that would already have replaced the power pack, stator, carbs etc.....Always check the basic, simple and cheap stuff first.