Power and ignition issues

DuckFan

Cadet
Joined
Jul 9, 2003
Messages
23
Perhaps some of you have had this issue and can help me:
I have a 1992 Mercury Mariner 60hp that I am having power and ignition issues with. The problem only seems to exist when I have been running the motor for a long period of time and working it hard such as running out in the ocean. The problem acts like a fuel demand issue. The motor will run along fine but then after a while 30 min or so, it will hiccup and stop. Then it I will start it back up again and hit the throttle only to have it sputter and die. Then I will start it up again and ease the throttle to about 1/4 but then when I give it any more it will sputter and die. I have completely gone through the fuel system including filter, pump, and even drained the tank. It seems to be getting plenty of fuel. I put brand new spark plugs in for this last trip out where it acted up again. I am wondering if it might be related to the coil or other ignition parts. It only seems to do this after it heats up and has been running for a while. If I let it cool down and get cold I can run it again for a period of time (30 min) before it starts acting up again. I have only experienced this problem in big water such as the ocean or large bay. Is there a way to check the electrical components to see if that is the problem? Do you think it is electrical? Is there an other possible cause to this issue that I have missed?
Thanks
DF
 

wtwe2step

Seaman Apprentice
Joined
Mar 21, 2008
Messages
36
Re: Power and ignition issues

Could be electrical. Do you have spark when it dies after getting warm?
 

DuckFan

Cadet
Joined
Jul 9, 2003
Messages
23
Re: Power and ignition issues

I have not been able to check for spark when it has heated up and died. It is a rare occasion that I work the motor that hard to get it to do re-create the problem. I did take it to a shop when I thought it was a fuel issue and they said that they could not get it to re-create the issue either. I am not sure how hard they tried. Should a shop be able to check for that spark issue fairly easily? I have had some people suggest that it is the stator. Is there a way that I could check that?
 

wtwe2step

Seaman Apprentice
Joined
Mar 21, 2008
Messages
36
Re: Power and ignition issues

It very well could be the stator but if it is only acting up when it is hot, it would test out in the shop. The trigger is another posibility. Does it happen more on hot days when the motor gets a little hotter? The best way to find out is to get it to happen and then test for spark to see what cyls have no spark. There are ohms and DVA test that can be performed but my guess is that they will pass the test when cold. The other option is to start replacing parts
 
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