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Jason
Jason, Marine Mechanic
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Experience:  Degree in Marine Technology. Gas and diesel marine mechanic.
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I have 2 Mercruiser 260 inboards, 1983 prox. Ran fine until

Resolved Question:

I have 2 Mercruiser 260 inboards, 1983 prox. Ran fine until recently. Port engine will crank but seems to get no ignition and does not respond to start spray either.
What should I check for this problem?
Submitted: 6 years ago.
Category: Boat
Expert:  Jason replied 6 years ago.

Hello, and welcome to Justanswer. My name is XXXXX XXXXX I will be helping you today. If you need clarification on something please post back here.

 

Hi there,

If it is an 83, you need to look into the points set an condensor. The ignition system works on an old fashion sysem, no different than 1955 automobiles. Points and condensor should be changed yearly regardless of hours, as the ignition system actually "wears and tears" and eventually will quite working with age and engine hours.

 

If you go by the book, Items such as points, condensor, cap, rotor and plugs should be changed yearly, again, regardless of hours. Spark plug wires every 3 to 5 years depending on useage and climate.

 

There are a few other things, but this is the most likely problem, an old fashion tune up. Start with this and if it does not fix it let me know and we can dig further.

 

Post right back here with any additional questions or concerns my friend.

Best,

Jason

 

 


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Customer: replied 6 years ago.

Mercruisers have Thunderbolt Ignition which do not have points, rather electonically fires from the optical, I think, signal from the distributor timer attached to the rotor.

Perhaps some things in the Thunderbolt system need checked as well as the distributor,etc for dirt and cracks?

Expert:  Jason replied 6 years ago.

I could be wrong, But it did not think thunderbolt 4 ignitions came out until 1985ish. Before that was points.

No problems though.

Here is a flowchart to troubleshoot that ignition system.

Follow the flowchart and it will help you narrow down what it is. The distributor uses a hall effect sensor inside of it. On the older ones the steel core was exposed, and they rusted up pretty good. (newer ones and replaces sensor are all encased in plastic so that does not happen) When you go to look at yours, if your sensor is a big ball of rust you can almost be assured that either is, or part of the overall problem.

 

 

Post back here with any additional questions or concerns my friend.

Good luck!

Jason

 

 

 

 

If this answers your question please do not forget to hit accept. Hitting accept is the only way justanswer compensates me for my efforts.
You can still come back here at any time in the future to ask follow up questions to this even after hitting accept.
If I have saved you considerable time/money, bonus tips are always greatly appreciated. Thanks!

 

 

 

 

 

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