this can't be normal..

[photoguy66]

I posted a few days ago about my 90hp merc problems and tonite I went and worked on it .problem is it is running rough, although it seemed intermittent at first. While it was running I pulled plug wires one at a time and noticed a difference in how it ran on all of them except #3.It made no difference when I pulled that wire, so I changed the plug(which looked as if it hadn't been firing)and switched the three wire with the #2 wire just to rule both of them out and still no difference. I have heard some motors only use some cylinders when idling so I upped the rpm's to 2000 and still no difference when I pulled the wire,I am guessing its a bad coil but just wanted some knowledgable input from you all. I did use a spark tester but I had very weak spark on the #3 and strong spark on the rest. I also noticed a lot of unburnt fuel in the water while it was running, it seemed more so than normal. Anyway thanks in advance for any replies.1984 90hp merc<br /><br />Rick

 

[stougas]

Re: this can't be normal..

Yes,<br /> Sounds like you need a new coil or plug wire. Make sure you check the coil ground before replacing the coil. Swap the coils between cylinders and see if the problem follows the coil. If it does you need a coil.