Seized 15hp Mariner, help!!

[longjohnsilver]

Several times during the season this engine was very difficult to turn over, had to pull with a lot of force on starter cord, but as soon as it allowed you to pull it would start immediately and run sweet as a nut.
At the end of the season brought it home, flushed it through with fresh water for approx 30 minutes, stopped it and stored it in the garage. I went to turn it over a few days ago and it would not turn even a fraction. Took the head off, cylinders both seem perfect, no scoring or rust marks. Put plenty of duck oil in each cylinder which drained away slowly over next day or so but still refuses to turn over.

I now think that the problem lies elsewhere, but unsure where to look. Has anyone had a similar problem and if so what do you suggest.

Thanks,
John

 

[chippie]

First, carefully inspect the starer mechanism to ensure that it is not jamming.
If not, try turning with a socket on top, if still siezed, separate the powerhead from the leg and then try to turn over. If it turns over the problem is lower down in the shaft/ gearbox. If not ; the powerhead will need further disassembly.
My thinking is that it is related to your starter and /or advance mechanism.
I am only posting from my general knowledge of outboards so I'm sorry that I cant be very specific re your mariner.
I am assuming that having taken the cylinder head off that you wont be too intimidated by removing the powerhead.
Please post and let us know how you get on.
Good luck.

 

[BarryH]

Had the same sort of problem with a Johnson 20 two stroke a few years ago, running fine then in store and it seemed to sieze, It wasnt actually siezed as you would think, apparently the residual 2 stroke lube had frozen the rings in the bores, try soaking with petrol and gently "rocking" the engine with a socket on the flywheel end of the shaft. It worked then and it could be the same now, check the compression once its freed, if it does, if it dont throw it away as some of the motors have chrome lined bores or so I've been told.

 

[pete]

Same thing happened to me earlier this year and I was convinced it was rust in the cylinders after removing the leg the engine turned over easily, it turned out to be a damaged inpellor and a impellor blade was jammed in the pump casing and when the rubber was dry it it had a tremendous grip on the pump housing.

 

[longjohnsilver]

Working again!

Thanks for your input, managed to turn it over this morning having taken the starter off.

No rust in the bores, will check the impeller as suggested.

Thanks again,

John