Yamaha 25HP might be overheating

[Rock Crusher]

So the family and I were on the river yesterday and my engine died on me twice and I was able to restart it both times but it acted like it was running out of gas. Then it died on me and I was not able to start it back up at all. I put my hand hand on the cowling and it felt very hot to the touch. We continued to fish for a couple hours and let the engine cool but it stgill didn't start and we had to take use the trolling motor to limp back to the ramp.

This engine had been having issues from the beginning. It would run perfect up until about 1/2 throttle and then would cut out and lose power until I backed off the throttle.

So today I pulled the carb off and rebuilt it and cleaned it very well. I also pulled the lower unit and inspected the impeller. The impeller was not terrible but dcoes need replaced. There were a couple fins that were a little messed up on the ends. So I am going to replace the impeller this week.

Do these engines have a thermostat in them?

I have not got to test out the carb rebuild yet and will wait until I get the impeller replaced. I started wondering if it was an overheating issue that was causing the engine to not run very well once I was trying to run in high throttle? So now I'm thinking maybe the engine might need a thermostat as well?

 

[Rock Crusher]

Left out that this is the 1995 C25 Yamaha.

 

[spotco2]

Yes they have a thermostat.

Look at 21 on the diagram

https://www.boats.net/parts/search/Yamaha/Outboard/1995/C25ELHT/CYLINDER%20CRANKCASE/parts.html

 

[Rock Crusher]

Thanks for the info! I tried looking at the parts schematics but I guess I didn't look in the right spot.

 

[turbotodd]

Take it to a lake, run it wide open until it starts to bog down. Then pull the choke lever out & see if it wants to take off & run any better.

If it does, it's starving for fuel.

 

[Rock Crusher]

Thanks, I will give that a try!

 

[Rock Crusher]

Is the vent screw on my tank supposed to be all the way open?

 

[rickybobbybend]

It is supposed to be open. If you have fuel delivery concerns be sure it is fully open.