2006 Honda BF 90 stalling issue

[MD Mate7]

I am posting this for my Father in Law who has been having an issue with his 2006 Honda BF 90 outboard.

Situation: Engine idles fine at pier but after 20-25 minutes of running it in gear, the engine sputters to low RPMs then shuts off. When this happens, the engine will not restart for 5-10 minutes. After restarting, engine runs fine for few minutes then shuts off again. It seems to be shutting off once it heats up.

At first, I thought the engine was getting starved of fuel so I replaced entire fuel system (fuel lines, fuel water separator, pick up tube, primer ball). I made sure all connections were tight. I checked old fuel water separator for water in fuel. I checked fuel in fuel tank for water. No water found. I added new fuel to tank, fuel water separator, and bled carbs to remove any old fuel.

To ensure fuel in fuel tank wasn't causing the issue, I connected a new portable fuel tank with new fuel directly to engine and engine still shut off as described above.

This led me to my current idea of engine overheating since I know its not a fuel related issue. No alarms sound when it shuts off, but we went ahead and replaced the thermostat in the powerhead. The carbs have been recently cleaned.

Researching online today, I believe it could be an issue with the CDI? Any advice/recommendations would be greatly appreciated. I'm stumped. Thanks in advance.

 

[ahicks]

My only thought is that replacing the 'stat is not going to provide much assurance the engine isn't getting hot. Have you checked the "pee" water temp?

Is the engine used in salt water? If so, and not maintained properly, it may have some pretty serious build up internally restricting the water flow. Still, you would think the alarm would sound to let you know.

My engine is an older one, but it seems like a I read that it would do do something if it got hot. I just don't remember if it went into a "limp" mode, or shut down completely.

 

[MD Mate7]

The engine is designed to go into limp mode if it overheats to ensure you can safely make it back to a pier. My engine seems like it wants to go into limp mode but then shuts off completely. The engine is used in salt water. I agree with the possibility of restricted water flow, but wouldn't that show a weakened "pee" as well. The engine pisses fine.

 

[ahicks]

What did the parts look like in the area of the 'stat when you had that apart? Was there a build up apparent?

Regarding the alarm, checking the temp switch by removing the wire to it and grounding it might be a worthwhile check for you.

Wish I knew more about it. I agree it sure sounds like a temp issue. Likely time to seek more advanced help.