Nevek
07-20-2013, 05:35 PM
This thing is killing me!
So I bought this boat in non running condition. It's a 15' Whaler powered by a 45hp 1988 Mercury Pro Fifty. It After a little tinkering, I was able get it to start and it ran great. Started right up, idled, etc. First time out on the lake and it ran like a champ, except an over heat alarm.
Basically, at idle/low speed it had no issues. Within a few seconds of hitting the throttle, to get it up on a plane, an overheat alarm would sound(steady beep). As soon as the boat came off a plane, the alarm would stop. The whole time the boat ran fine, with water coming out the tell tale and no obvious issues...just a pesky alarm.
I pulled the lower unit and replaced the impeller, wear plate, and both gaskets. Took the boat out again and had the same issue. So I pulled the power head and replaced the gasket from power head to exhaust plate, the gasket from the exhaust plate to the cowling, both seals for the water tube and a few non-cooling related issues. Also, two tiny cooling passages were clogged up. You couldn't even see them until I filled the cooling passages of the block with vinegar and started cleaning. I flushed and back flushed a bunch of times with water and vinegar until I felt I got most of the build up.
We took the boat out again today and I still have the exact same issue and then some. Not only do I get the same alarm, but i'm down on power so much that the boat wont get on a plane unless I really mash it and have no one in the boat.
Today, I brought my infrared laser thermometer and the hottest the motor ever got (surface temp) was 140*. The tell tale was hot, but you could still keep your hand under the tell tale without issues. I'm starting to think the motor isn't overheating, but something is up with the sensor. We were in the middle of the lake, with the engine cold/sitting for a while. A storm started rolling through and we had to make a run to the boat ramp. We started the motor, mashed it and headed for the ramp. Within 15 seconds of starting, the alarm went off. I doubt the engine is gonna go from room temp to overheating that fast.
What do you guys think? What can I check next? I'm debating dropping it off at the mechanic because it seems to be over my head but I would hate to have done all that work and then find out it's something stupid.
What do you think?
So I bought this boat in non running condition. It's a 15' Whaler powered by a 45hp 1988 Mercury Pro Fifty. It After a little tinkering, I was able get it to start and it ran great. Started right up, idled, etc. First time out on the lake and it ran like a champ, except an over heat alarm.
Basically, at idle/low speed it had no issues. Within a few seconds of hitting the throttle, to get it up on a plane, an overheat alarm would sound(steady beep). As soon as the boat came off a plane, the alarm would stop. The whole time the boat ran fine, with water coming out the tell tale and no obvious issues...just a pesky alarm.
I pulled the lower unit and replaced the impeller, wear plate, and both gaskets. Took the boat out again and had the same issue. So I pulled the power head and replaced the gasket from power head to exhaust plate, the gasket from the exhaust plate to the cowling, both seals for the water tube and a few non-cooling related issues. Also, two tiny cooling passages were clogged up. You couldn't even see them until I filled the cooling passages of the block with vinegar and started cleaning. I flushed and back flushed a bunch of times with water and vinegar until I felt I got most of the build up.
We took the boat out again today and I still have the exact same issue and then some. Not only do I get the same alarm, but i'm down on power so much that the boat wont get on a plane unless I really mash it and have no one in the boat.
Today, I brought my infrared laser thermometer and the hottest the motor ever got (surface temp) was 140*. The tell tale was hot, but you could still keep your hand under the tell tale without issues. I'm starting to think the motor isn't overheating, but something is up with the sensor. We were in the middle of the lake, with the engine cold/sitting for a while. A storm started rolling through and we had to make a run to the boat ramp. We started the motor, mashed it and headed for the ramp. Within 15 seconds of starting, the alarm went off. I doubt the engine is gonna go from room temp to overheating that fast.
What do you guys think? What can I check next? I'm debating dropping it off at the mechanic because it seems to be over my head but I would hate to have done all that work and then find out it's something stupid.
What do you think?