Coil overheating on MerCruiser Sterndrive 165hp on 1978 SeaRay SRV-187

Kuttawa

Recruit
Joined
Jun 13, 2010
Messages
3
New to the forum and have searched for this problem but can't find any info.

I just got a 1978 Sea Ray SRV-187 with a 165hp straight six Mercruiser.

I was told that it needed a new starter solenoid because it clicks sometimes when you turn the key to start it.

I put all new spark plugs in it, new gas, a pint of seafoam in the gas, changed the oil and oil filter.

I was planing to order the new starter solenoid Monday and replace it when it came in.

It started up after a few cranks at home hooked to a water hose with earmuffs and I let it run for about 5-10 minutes.

Then we took it out on the lake and it started and ran fine on the water. We ran it around for about 20 minutes and stopped in a bay to swim.

After it set for an hour we wanted to try and ski behind it so I tried to start it and it would turn over but not start.

When trying to start it (even before we got to the bay) it sounded like the battery (which I had fully charged the night before) wasn't really giving it enough power.

I had a look at the motor and heard a crackling sound and noticed that the ignition coil was very very hot. So hot that it was making noise and if a drop of water touched it it would evaporate instantly.

The boat never started and I had to be towed back to the dock.

I also noticed that the ignition coil would not cool down until the battery was unplugged.

That was yesterday. Today I plugged the battery back up and within 10 minutes the coil was very hot again without me even trying to start it.

I also noticed under the seat an old starter solenoid and ignition coil that had previously been replaced. This made me think that maybe there is something causing these parts to go bad.

I'm not a mechanic but I am comfortable replacing parts and I can get help from my friends. I don't want to take it to a marina where they charge $90 per hour because I will end up spending more than the boat is worth.

So I guess I have 3 questions:

What do you think is wrong with it?

I'm fine replacing the coil but I'm worried about what is causing it to go bad. Is there something else I should check?

and

Can anyone give me a checklist or a link to one that has everything you should check or replace to get a used boat in good working order?

Thanks for your help!
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,111
Re: Coil overheating on MerCruiser Sterndrive 165hp on 1978 SeaRay SRV-187

Should not be powering up just by hooking up the battery. Shorted ign switch?. Modified wiring system?
 

Kuttawa

Recruit
Joined
Jun 13, 2010
Messages
3
Re: Coil overheating on MerCruiser Sterndrive 165hp on 1978 SeaRay SRV-187

How can I tell if the ign switch is shorted out?

The wiring does look very shady.

Is there any way for me to find out the correct wiring so I can replace the wires?

I ordered this service manual:
http://www.amazon.com/Mercruiser-Drives-Marine-Tune-Up-Manuals/dp/0893300055/ref=pd_sim_b_1

Do you think it would have a wiring diagram and specifications on what type of wire to use?
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,111
Re: Coil overheating on MerCruiser Sterndrive 165hp on 1978 SeaRay SRV-187

The ones in the Adults Only section are free and do have the needed wiring.
 

Kuttawa

Recruit
Joined
Jun 13, 2010
Messages
3
Re: Coil overheating on MerCruiser Sterndrive 165hp on 1978 SeaRay SRV-187

Thanks!
 
Top