Got a strange problem on a 75 Merc 9.8

[rogerwa]

I just picked up this Merc 9.8. it runs great now that I pulled the carb and cleaned and adjusted the float and needle.

The only problem I have is that it arcs somewhere under the cover at low speed. When i pull the cover off it is fine. The cover is composite, and inspection on the inside doesn't reveal any marks where the arcng could occur.

The only metal under the cover is the cover latch. I am thinking the lower plug wire must be arcing through the boot to the cover latch and then grounding as it passes to the latch recepticle.

Inspection of the boot show some scuffing, no marks or anything.

Any other ideas??

 

[Laddies]

Re: Got a strange problem on a 75 Merc 9.8

Thats about the only place it can arc

 

[rogerwa]

Re: Got a strange problem on a 75 Merc 9.8

I looked at replacing the plug wire from the coil and not sure if it is supposed to be removed. I tugged on the wire and it did not come off.

The coil is orange, if that matters, and I do not know if it is original. should I tug harder or is the plug wire attached to the coil??

 

[dajohnson53]

Re: Got a strange problem on a 75 Merc 9.8

I looked at replacing the plug wire from the coil and not sure if it is supposed to be removed. I tugged on the wire and it did not come off.

The coil is orange, if that matters, and I do not know if it is original. should I tug harder or is the plug wire attached to the coil??

I'm going to assume your '75 is the same or similar to my '74. (orange coils sounds the same). My plug wires have a rubber boot at the coil end and they definitely don't come off easy. I've found if I roll back the rubber first, they come easier.

How do you know it's arcing - I'm just curious what you're seeing /hearing or symptoms.

 

[rogerwa]

Re: Got a strange problem on a 75 Merc 9.8

So the wire does come off then??

What I am hearing is a distinct arc sound accompanied by a miss at low speed. this only happens at low speed with the cover on.

I pull the cover off and it runs fine. I cannot find any trace on the wires or cover that I can associate with arcing.