86 Mariner 60hp had weak spark now none...

ydduit

Cadet
Joined
Jun 9, 2006
Messages
7
I have a 1986 Mariner 60 HP that was getting increasingly hard to start last season. I determined that I had weak spark on all three cylinders (yellow spark that had a hard time jumping 1/8" gap) and the engine just didn't have any power (on a 17' alumacraft with fishing gear and my 300 pounds it wouldn't plane and top GPS speed was 13-17 mph)...

Fast forward to this week, I was getting things ready for the fishing season and had started the engine...I ran it on muffs and it started very hard (cranking for 5-10 minutes before it would even attempt to fire...I wasn't sure if it was weak spark or just sitting all winter that caused it to be so hard to start). Once running it sounded and acted like it should. I let it run for about 15-20 min to charge the battery and shut it down. I then tried to start it again right away. Same problem, I cranked and cranked for what seemed like for ever before it finally fired, but once it fired up, it acted ok. This morning I bought an adjustable tester to verify that it did indeed have a weak spark and while testing I found that I no longer had a spark on any of the cylinders.

Where should I start to troubleshoot this? Does it sound like my stator was going last season and finally crapped out on me today? Any help is appreciated as electrical testing is my weak point and in looking at my Seloc manual, test procedures are not very clear...
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: 86 Mariner 60hp had weak spark now none...

First thing is to charge that battery, and clean BOTH ends of the battery cables, also clean the short cable that links the starter to the relay.

This ignition has a minimum cranking speed of 300 RPM to generate enough voltage to function. Slower cranking can give a weak or no spark condition, even tho it seems to crank OK.

Second, get a DVA Meter and download the FREE Ignition Troubleshooting Manual using the link found at www.rapair.com

This will guide you in step by step testing of the ignition system to determine any fault.
 
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