1992 Evinrude 15hp..... Started to lock up....

#-o I was out saturday morning duck hunting and went through some muddy mulch-like crud in the water for about 25 yards.... well the dew point was very low that morning and you could blow smoke easily with your breath, well there was quite a bit of smoke coming out of the motor so just to be safe I killed the motor and made sure I cleaned out the water pick-up. I ran it at about 1/4 throttle for about another 100 yards to get to the blind. Well we hunted the morning and when we went to leave the motor didn't want to start. It usually starts on first or second pull but this time it took 15 or more. It started (no smoke) but wouldn't really rev and 30 seconds later is quit and the motor wouldn't really go in and out of gear (not running). I got it in neutral and started it again (15 or more pulls) and it ran for about 10 seconds until it slowly reved down and then I couldn't pull the pull-cord. (locked up felt like). Well we paddled out and after about 20 minutes of paddling I easily pulled the pull cord and it would pull through again but I obviously didn't try and restart it.

1st. I'm guessing that the water pump is clogged with that mulch-ie crap. I'm going to drop the lower unit tonight and clean all of the stuff out.
2nd. I wonder how much damage was done to the cylinders. Probably scored but since I was only at 1/8th to 1/4 throttle when the rings expanded and seized the motor I doubt much damage was done. [-o<

Is there anything you guys would recommend me doing other than what I've stated? Is there anything else to flush out? I don't really want to pull the heads if I don't have to.... and I hope my 15hp isn't a 9.9 now. #-o

First thing I'd do is take a compression reading & go from there.

If the engine sounded like brakes being applied to the flywheel when it stopped then you have issues. Second, the rings do not expand and stop the engine......the pistons expand and stop it,... much more expensive. Third, you might find that you have compression but with scored cylinders and piston skirts you may have a poor idling and a hard starting engine. If you find that you have to raise the idle speed and richen the mixture some to make it idle then you have damage. The statement you made about being hard to get out of gear once seized indicate piston to cylinder seizure and probable metal transfer or loss. If you could not rotate the flywheel immediately to get the engine out of gear that further indicates a hard seize. If the engine freed up after a couple minutes or more that again is a clue. Hard re-starts indicate loss of crankcase compression (not necessarily piston compression).There are two types of compression a two-stroke must have to operate normally, the second type is crankcase compression which you may now be lacking in and there are no checks that can be made for this and no reference numbers to go by. Crankcase compression is what pulls the fuel/air charge into the crankcase and then pushes it through the intake ports and on top of the piston. On the overheating issue you had. The water pump impellers on that series of engine definitely take a set over the years since they are under alot of compression and will not pump efficiently once this happens. For those reading this, a weak or intermittant stream at idle is your first clue. When I used to Duck hunt down in Lake Okeechobee we always used double oil as we knew we would be starving the engine of cooling occasionally. Do not put any faith in piston comrpression once an engine has seized . It would be wise to remove the intake by-pass cover on the weakest cylinder and take a look at the bore through the ports.

Thats the thing. There was no bearing sound at all. I really hope that the motor isn't F-ed' but I have a sinking feeling.

Huh?? You won't get a bearing sound when a two stroke engine sticks a piston. Chances are the bearings are still good. Re-read my post and let it sink in a while. Your post has all the information needed to tell me the engine stuck a piston or pistons (seized). If you do what I wrote you will know what happened.

LFTDJEEP426 said:

#-o I was out saturday morning duck hunting and went through some muddy mulch-like crud in the water for about 25 yards.... well the dew point was very low that morning and you could blow smoke easily with your breath, well there was quite a bit of smoke coming out of the motor so just to be safe I killed the motor and made sure I cleaned out the water pick-up. I ran it at about 1/4 throttle for about another 100 yards to get to the blind. Well we hunted the morning and when we went to leave the motor didn't want to start. It usually starts on first or second pull but this time it took 15 or more. It started (no smoke) but wouldn't really rev and 30 seconds later is quit and the motor wouldn't really go in and out of gear (not running). I got it in neutral and started it again (15 or more pulls) and it ran for about 10 seconds until it slowly reved down and then I couldn't pull the pull-cord. (locked up felt like). Well we paddled out and after about 20 minutes of paddling I easily pulled the pull cord and it would pull through again but I obviously didn't try and restart it.

1st. I'm guessing that the water pump is clogged with that mulch-ie crap. I'm going to drop the lower unit tonight and clean all of the stuff out.
2nd. I wonder how much damage was done to the cylinders. Probably scored but since I was only at 1/8th to 1/4 throttle when the rings expanded and seized the motor I doubt much damage was done. [-o<

Is there anything you guys would recommend me doing other than what I've stated? Is there anything else to flush out? I don't really want to pull the heads if I don't have to.... and I hope my 15hp isn't a 9.9 now. #-o

Click to expand...

Not one word about the tell tale. [-X

Tell-tales are the first thing to plug up with debris, mud, whatever. Wouldn't have mattered here.

In case anyone cares, I'm pretty sure I found the problem with my motor this weekend. There was a bad shift linkage seal that was somehow binding the shift lever. I replaced the seal and everything seemed fine. I don't know if this was all of the problem but the motor starts 1st or 2nd pull again and runs fine. I took it out yesterday evening and ran it for about 30 minutes of 3/4 throttle to full and no problems! Kind of weird but I hope she's okay! #-o

LFTDJEEP426 said:

In case anyone cares, I'm pretty sure I found the problem with my motor this weekend. There was a bad shift linkage seal that was somehow binding the shift lever. I replaced the seal and everything seemed fine. I don't know if this was all of the problem but the motor starts 1st or 2nd pull again and runs fine. I took it out yesterday evening and ran it for about 30 minutes of 3/4 throttle to full and no problems! Kind of weird but I hope she's okay! #-o

Click to expand...

Good for you - thanks for teh update.


Where do you live that you can run a boat - certainly not here in the NE part of the country

Sunny Florida! 8)

Good to here!

Sorry if I came off as mean.
I get tired of hearing about people killing good motors.

LFTDJEEP426 said:

Sunny Florida! 8)

Click to expand...

Add it to your profile please

Although the seal does not explain what was happening in your first post am happy it is running for you. Would definitely check the engine out a little further before restoring much faith in it. Depending on what part of Florida you are out of you are welcome to come by the shop and bring the engine. Located in Central Florida.

i totally agree on not totally trusting it yet. I'm that way with everything regardless if it's acted up before or not. I know that it doesn't explain it locking up for that brief period but the plugs looked fine both cylinders had within 2 lbs of compression..... I really don't know what the deal was..... I did determine that there was a decent amount of crud in the thermostat which is what probably kept the water from flowing not the pump being clogged as I initially thought. I'll definitely keep diagnosing as I go and thanks a ton for all of you guy's input!

What was your compression numbers? By the way, what seal did you replace?? On the parts breakdown I see only one seal, located in the gearcase which means a complete disassembly, requiring a special tool to line up the shift cradle. There are no seals for the shift shaft located anywhere under the powerhead or in the midsection that I can see. Take a look at these and let me know. https://epc.brp.com/Index.aspx?lang=E&s1=46c7b3f0-2ad1-4688-9f94-e09528958909 plus this one https://epc.brp.com/Index.aspx?lang=E&s1=46c7b3f0-2ad1-4688-9f94-e09528958909 and here is the one for the gearcase https://epc.brp.com/Index.aspx?lang=E&s1=46c7b3f0-2ad1-4688-9f94-e09528958909