92 Mercury Classic 40hp Issues

FishAK

Recruit
Joined
Jun 26, 2013
Messages
1
I recently got a 92 mercury classic 40hp 2 stoke outboard. I went to change the spark plugs because the previous owner says they foul out and he changes them a couple times a year. I brought in an old plug to the mercury shop when I got my new ones, but they said they weren't the right plugs and gave me the correct ones. I checked the manual and they did give me the right plugs, however after I installed them the outboard wouldn't start. I put the old plugs back in and it started up. Could that be a weak spark issue? Not sure why the incorrect spark plugs start over the recommended plugs. Any input would be great.

Also, I have been having some issues like it dying under load at low throttle and dying at idle after idling for 30 seconds or so. It seems to run decent out of the water with the garden hose attached. I did some research and am thinking I need to do a carb rebuild. It also seems a little sluggish. This is my first boat so I have nothing to compare it to. I reach about 19-22mph at full throttle, does that sound about right? Motor is on a 17' welded aluminum skiff. If anybody has any other suggestions that would be great. Thank you.
 

Yesterday

Petty Officer 1st Class
Joined
Feb 21, 2012
Messages
354
Re: 92 Mercury Classic 40hp Issues

Top speed sounds about right. Idle for 30 seconds then dying, sounds like plug foul or too much fuel, effectively flooding it what is your idle air screw set at?. Perhaps others may have more useful suggestions.
 
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