1988 mercury 45 hp. runs on 3 cyl then 4

Status
Not open for further replies.

mbp102

Recruit
Joined
Jul 31, 2003
Messages
2
I have a 1988 mercury classic 50 45hp. Most of the time it will not fire the top cylinder. The top rpm is about 4200. Then at times the top cylinder will fire and get up 5200-5400 rmp. I have used an inline spark tester which shows the problem. I have also switched the plug wires and plugs but top cylinder always has the problem. My guess is that the coil is bad, but is it possible that it would work sometimes but not all the time. Does anyone have any thoughts on this. <br />Thanks, <br />Mark
 

The Marine Doctor

Commander
Joined
Jul 25, 2003
Messages
2,177
Re: 1988 mercury 45 hp. runs on 3 cyl then 4

Yes...coils generally work until they warm up. Although..so does the power pack.<br /><br />Take and switch your coils around and see if it fails still.<br /><br />If not..time to change the powerpack.<br /><br />TMD
 

Outboard dumbie

Recruit
Joined
Nov 21, 2019
Messages
1
I seem to have the same issue with my 1988 45hp mercury classic 50. I've switched the coil from 2 to 1 and still no spark on #1 cylinder. No matter what I try. There is no spark on the #1 cylinder. When we ground the plug wir we get spark so, it seems to be a ground issue on the #1 plug but I'm not sure how to fix it. Any help?
 

The Force power

Commander
Joined
Feb 3, 2019
Messages
2,241
I seem to have the same issue with my 1988 45hp mercury classic 50. I've switched the coil from 2 to 1 and still no spark on #1 cylinder. No matter what I try. There is no spark on the #1 cylinder. When we ground the plug wir we get spark so, it seems to be a ground issue on the #1 plug but I'm not sure how to fix it. Any help?


welcome to IBoats, read the intro about postings first

https://forums.iboats.com/forum/forum-rules-and-guidelines
Then
here's a link to diagnose
http://www.cdielectronics.com/wp-con...de-Digital.pdf
 
Status
Not open for further replies.
Top