15 Johnson water in crankcae

[Robert S. Davis]

77 Johnson 15 hp, 15E77M,
Engine starts and runs fine except! Starts out fine under load, shortly it begins to labor and hesitate, removed plugs, top is fine, lower plug has water accumulated in recess around electrode and some on tip. Clean the plug and it will water foul again in just moments. I'm getting water into the crankcase (from the water pump) indicating a gasket, hole in plate etc. Where should I start to find water intrusion point? What is the most likely culprit? Should I just disassemble and replace all gaskets? What area is the most likely to fail? As you can probably tell, I want to eliminate the easiest to repair first. Thanks for any help

 

[crxess]

Re: 15 Johnson water in crankcae

Start with a compression test. If the cylinder is low it probably needs a head gasket.

 

[Robert S. Davis]

Re: 15 Johnson water in crankcae

I'll test compression tonight and see if there is a difference between top and bottom cyl. Will head remove OK without taking power head completely off?

 

[jay mendoza]

Re: 15 Johnson water in crankcae

Yes, the head comes off without removing the power head, it's a bit tight, a wobble extension for your ratchet and socket helps. Remove both plugs first.
You might also check if one of the six head bolts is loose first, just in case.

 

[Rick.]

Re: 15 Johnson water in crankcae

It is also possible it is coming in through the exhaust plates/gaskets. I just re-torqued mine and the leak (water) stopped. I was getting it only in the lower cylinder. An easy fix if that is where it's coming from. Best of luck. Rick.

 

[Robert S. Davis]

Re: 15 Johnson water in crankcae

I checked compression cold with electric start, top is about 108 bottom is 110.
I don't see a great difference in either cylinder. I'll check torque on all bolts. If I have to replace exhaust plate gaskets as well as head, I would just as well pull the power head and replace the bottom gasket too? It will be a few days but I'll post what I find.

 

[Rick.]

Re: 15 Johnson water in crankcae

To replace exhaust plate gaskets you do have to pull the power head. If your going to do that I would suggest replacing the water tube grommet at the same time. But, you may well try to just re-torque them first. Your compression numbers are fine IMO. Wish mine were that good. Rick.

 

[Robert S. Davis]

Re: 15 Johnson water in crankcae

All bolts (that I can get to) seem tight. I've ordered a power head gasket set from i.boats. Should be here by the end of the week. If possible I will tear it down this weekend. Thanks for the encouraging help.

 

[Robert S. Davis]

Re: 15 Johnson water in crankcae

Installed head gasket and both side cover gaskets along with new base plate gasket. Head gasket looked like it was possibly seeping and the side cover gaskets were soaked. No definitive area where I can say there is the leak, but I would think the major area was in the head gasket area.

Reassembled and set out on my lake, was a bit cold natured at first but leveled out and ran fine. Idled good and hole shot was steady without skipping. With GPS in registered 21mph pushing a 14-46 Duracraft with just me in the boat with battery and fuel tank.

Thanks for the help. (CAN'T FIGURE OUT HOW TO POST PHOTOS or I would send pictures of the gaskets.)