Lund Fisherman 2000

Woohoo first post, newish lund owner. I’m looking for insight into an overheating problem I have been having with my kicker motor.

It’s a 15hp Honda four stroke, it’s an 04 and from what I have been told from the previous owner who owned it for those 18 years is that he rarely ever used it and believes there’s less than 10-15 hours on the motor. Spark plugs were replaced a year ago.

The problem I’m having is that after running for 10 minutes just at idle the temp alarm kicks on and will cut the motor. There is water coming out of the tell tale and I have taken out the thermostat and that looks brand new relative to its age. I have yet to check the oil/water separator and take the water block off. Thinking it could be a piston ring maybe.

Just looking to see if anyone else has ran into this problem, thanks!

Just because the stat looks good doesnt mean its working properly, pull it back out and put in water that has been heated to the stats opening temp to make sure it is in fact opening.
I have also seen countless times where even though the telltale is peeing the water pump is on its last legs and in need of replacement.
If I remember correctly, ( its been a few months ) some/most Honda outboards turn counterclockwise and you have to keep that in mind when replacing the impeller so that it is clocked correctly or it wont work right.