Mercruiser Coils and Sea Start

[moonshine33uk]

My Mercruiser 5.0L is eating coils. This is dangerous as today I ended up anchored off a lee shore in quite rolly conditions waiting for Sea Start to arrive whilst Solent Coastguard monitored the situation. Oooh er.

Facts: Boat had a mega (£1100) service when bought in May 2004. Coil was replaced. Don’t know why. Boat had been stored ashore for over a year. Guess the engineers saw/heard something they didn’t like.

Ran ok until end of September 2004. Coil failed. Was arcing badly. Replaced under warranty by another Company. Batch numbers were the same. Thought was a faulty batch. Noted that battery was charging at 14.58 volts at 4000 rpm.

Boat ashore end of September 2004.

I bought it.

Launched today after another mega service. Engineer actually came out on the sea trial. All ok until 20 miles later the engine died. Coil arcing again. Sea Start covered it in grease to stop arcing and engine fired immediately!

Anybody got any experience of this fault or bright ideas? Thanks in advance.

Further to previous threads Sea Start were amazing. Towed me to Lymington and then spent an impressive amount of time trying to working on the problem. Highly professional and recommended.

 

[corncob]

The coils suffering from carbon tracking. Remove the coil lead, lightly coat the lead and boot with diaelectric grease. Should sort the problem.

 

[Its_Only_Money]

What causes carbon tracking, I've always thought a clean, dry coil would be OK unless it failed internally? Is it standard practice to have to coat coils in this grease or is it a mercruiser special requirement due to the coil design?

 

[corncob]

Carbon tracking is just a name that the americans refer to? I belive this can be related to moisture on the coil. Diaelectric grease disperses the moisture and prevents arcing. However, it has been known for the coil to split at the top of the tower, its usless if this is discovered. cheap coils thats the problem, not designed for marine use!

 

[moonshine33uk]

Thanks a lot um where do I buy the grease? Never heard of it. /forums/images/graemlins/confused.gif

 

[Its_Only_Money]

Sound's like a better quality coil might be a better fix!?!?

Maybe mercman can advise???

 

[Oldhand]

Or change to diesel power?....

 

[Col]

Depending on year / ignition you may have a non ballasted coil system with a ballasted coil fitted. If you know the year or the ignition type I may be able to tell you which type you should have.

 

[moonshine33uk]

Hi Col the engine is 2000. It is a 5.0L carb V8. Thanks Steve

 

[Col]

Should have thunderbolt ignition Non ballasted coil. If you have a coil designed for a ballast resistor, you will overheat coil and it will burn out. Make sure you have 12V HEI coil fitted.

 

[corncob]

moonshine you can get dieletric grease from any outboard/inboard dealer, i will check and let you know. I would also replace the HT leads, if they are old, tension builds up putting excess load on the coil.