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'73 Mercury 1500 I6 shutting off after aprox 15 mins

M

mimercdude

New member
Hello everyone,
New member here. I am assisting a friend and am hoping someone can help us out, we have done some searching but so far no luck yet. We have.
1973 mercury outboard model 1500 150hp Inline 6
Sn 362xxxx USA model
Thunderbolt breakerless ignition

The engine will run for about 15 minutes then shut off, when the engine does shut off it is immediate.
After allowing things to cool for about 10 mins the engine will start right back up and run for about 15 mins then shut off again.

Found failed bearings in the distributor that may have been overheating the trigger.
Also checked the coil and found it is less than 0.1 – 0.2 ohms on the primary side and 330 ohms on the secondary side.

We are unable to find the exact specifications for this coil and would like to know.

Based on the ohm readings could the coil be bad?
Would anyone know what the coil resistance should be?
Could the overheating bearings be causing the suspected trigger issue?
We are suspecting the overheating bearings because the distributor got so hot it melt the grease out of the economizer.

We are also certain the engine is not overheating, the water pump has been replaced and the tell tale outlet is continuously discharging water.
The engine stays cool enough that I can hold my hand on the cylinders.

Pic of the coil attached.
coil.jpg

Thank you for any assistance.
 
That particular coil never fails, so look at the distributor. It can NOT be rebuilt, however--you'll need to find another one. It's also very hard to take apart without destroying that aluminum 'finger' above the timing disk.

Jeff

PS: I assume yours is the usual bolt on cap distributor. If you have the rare bolt on cap distributor, however, I have a trigger coil I'll give you--just pay postage.
 
Thank you for the replies. We have new bearings that will be installed an tested soon.

Fastjeff - Thank you for the offer. I am not sure what type of cap distributor we have. Did you mean the usual NON bolt on cap distributor instead of the "usual bolt on cap distributor" in your first sentence? I would say this is not a bolt on type, I'll include some pics, hopefully it can be confirmed.

Ill post up another update when we try the new bearings. We won't ignore the trigger either.

IMG_1391.jpgIMG_1392.jpgIMG_1393.jpg
 
That's the usual camp-on cap deal. If the circuits in there check out, you might be able to repair it by changing the bearings, but it's like defusing a bomb!

Have you checked the black/ brown/ white wires for resistance?

Jeff
 
Providing another update. We got everything back together and tested it with a water hose. Ran the engine for about 20 minutes without any issues. Still need to get it in the water for an official test but so far things are looking promising.
 
fastjeff said:
That's the usual camp-on cap deal. If the circuits in there check out, you might be able to repair it by changing the bearings, but it's like defusing a bomb!

Have you checked the black/ brown/ white wires for resistance?

Jeff
Click to expand...

I meant to reply to this much sooner. Those wires are for the trigger correct? They were not checked. What resistance should be seen when measuring those?

I will say my friend was able to run the boat in the water this past weekend, I was not able to join him. He ran it for about 3 hours without any problems. So it appears the bearing replacement and cleaning made a difference.
 
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