View Full Version : 15 hp Sea King power issues

03-26-2013, 10:40 AM
Hello everyone,
I'm hoping someone here can help me. I've already been to two different local marine shops and no one seems to know how to fix my problem.
I'm running this 15 hp sea king on a 14 ft starcraft aluminum boat. Here's the problem.
I put a new set of spark plugs in the motor, and took it to the lake, it ran GREAT! Pushed my boat up to 21 mph, Went back to the truck to get a couple fishing rods, shut the motor off, loaded up my gear, and took off again. And that's when I started having a problem. Top speed, 10 mph. That really had me scratching my head. I checked fuel, plugs, timing, everything I could think of, Still no power.
After I let the motor sit for a while, it started to run strong again, until I shut it off.
My first thought, was something getting overheated, so I decided to take it out and run it wide open for a while to see if it would start having problems after running for a long period of time. I ran around the lake for an hour at 20+ mph, not a single hesitation. Shut it down, same problem, no power. Let it sit for about an hour, fired it up and it ran strong, ran it for about 10 mins shut it down, and no power again. I'm at my wits end with this motor, any help would be greatly appreciated.

Thanks in advance for any help you can offer.

deer farmer
08-07-2013, 08:01 AM
what spark plugs are you using?do a compression test cold then after it is heated up.