Hey guys,
I purchased a little speed boat on Friday, it's a 16 footer with a Merc 65 hp outboard. The boat was not in the water when i went to see it, so we put some muffs on her and she fired right up without issue. Revved nice and the water pisser was working well. So i made the transaction and took it out to the local lake to test it out.
It ran well from what i could tell. No bogging at all, slightly rough idle but not bad. After running the lake at WOT for about 5 minutes. I slowed down as i realized the gas hose popped off, so i stuck it back in. Then i hit the primer, and restarted it, good to go. After cruising at half speed for one minute, i started to loose power and sure enough she died on me. I opened the casing of the cowling and it was smoking good, and very very hot. So i loaded her up and checked it out at home.
I performed a compression test and found cyl 1 - 40psi, cyl2 - 115psi and cyl 3 - at 120 psi. So clearly i overheated to first cylinder and probably melted the ring/piston.
When i pulled the plug out of the top cylinder it was like a white color, and looked very rough. Almost lean.
So, of course this is frustrating as i owned the boat for an hour. I have rebuilt my two stroke dirtbike many times, but outboards are new to me. Is this a relatively easy job to replace the piston and ring?
I cant seem to find any instructions.
Also, why would this have happened? I will end up dropping the lower unit and checking the impeller, but is that the only thing that moves water into the water jackets? maybe something is clogged in there.
I purchased a little speed boat on Friday, it's a 16 footer with a Merc 65 hp outboard. The boat was not in the water when i went to see it, so we put some muffs on her and she fired right up without issue. Revved nice and the water pisser was working well. So i made the transaction and took it out to the local lake to test it out.
It ran well from what i could tell. No bogging at all, slightly rough idle but not bad. After running the lake at WOT for about 5 minutes. I slowed down as i realized the gas hose popped off, so i stuck it back in. Then i hit the primer, and restarted it, good to go. After cruising at half speed for one minute, i started to loose power and sure enough she died on me. I opened the casing of the cowling and it was smoking good, and very very hot. So i loaded her up and checked it out at home.
I performed a compression test and found cyl 1 - 40psi, cyl2 - 115psi and cyl 3 - at 120 psi. So clearly i overheated to first cylinder and probably melted the ring/piston.
When i pulled the plug out of the top cylinder it was like a white color, and looked very rough. Almost lean.
So, of course this is frustrating as i owned the boat for an hour. I have rebuilt my two stroke dirtbike many times, but outboards are new to me. Is this a relatively easy job to replace the piston and ring?
I cant seem to find any instructions.
Also, why would this have happened? I will end up dropping the lower unit and checking the impeller, but is that the only thing that moves water into the water jackets? maybe something is clogged in there.