Water in the crankcase questions? 115 Johnson crossflow

[GatorMike]

Last year I started noticing from time to time some rust on the lower left spark plug and suspected a problem. Well the problem didn't just go away, in April my motor froze up and I had to tear it down and rebuild it. I suspected the water got in through the exhaust cover/manifold and was about 90% certain. The lower right cylinder was rusted up solid and the lower left was pretty rusted too, the two upper cylinders had surface rust but weren't too bad. After the rebuild I got 3 or 4 months of service out of it. Two weeks ago I was out and about midway through the trip my motor started missing real bad.

I finally got the chance to work on it yesterday and when I went to start it the motor was froze again. I sprayed a little oil into the cylinders and let her sit. Then I put a breaker bar on the flywheel nut and broke her loose. I started her and let her warm up then did a compression test. When I pulled the plugs the lower left was wet and all 4 showed signs of rust. The compression test came out good though.

Today I pulled the heads and the head gasket on the lower left has a couple of questionable areas on it. Some of the gasket material between the two cyls is missing and also some material is missing at the bottom of the botom cyl. I'm not sure if this is a problem and not even sure it was leaking, the metal rim around the hole in the gasket was still intact.

OK here are my two possible theories at this time.
1. My rebuild in April fixed the problem I originaly had and this is a new problem. The reason my motor started running poorly the last time out was because I blew a head gasket and the lower cylinder was getting water in it therefore I was running on 3 cyls.

2. I never actually fixed the original problem, because my first 8 or 10 trips out after the rebuild were freshwater trips I never had a problem with rust in the crankcase. The last couple of trips out were saltwater trips and I got enough saltwater in the crankcase to cause major rusting again. The poor running the last trip out is an unrelated problem.

I'm not sure what the case is here. My gameplan right now is to replace the head gaskets and try her out. If that doesn't stop the water I will try to remove the exhaust cover and replace it. Not sure if this can be done without removing the powerhead but it is worth a try. If that doesn't work I guess I am in for another tear down.

Now a couple of questions:
With water intrusion into the crankcase does that water drain out or does it just sit in the crankcase when the motor isn't running? I would assume with all the moving parts once water is inside the crankcase it is blown around to all cylinders therefore no matter where it gets in you are going to see some signs of water everywhere? Since the lower left cyl is the lowest of the 4 wouldn't it always show the most signs of water reguardless of where the water is getting in?

I'm just trying to grasp a better understanding of what is going on inside my engine.

Thanks,
Mike

 

[emdsapmgr]

Re: Water in the crankcase questions? 115 Johnson crossflow

What year is this? OMC made both a bubble back and a flatback engine in the 115 hp configuration. The engine should drain all the water out when shutoff, if the engine is vertical. Water intrusion can be from two areas on a crossflow. If the head gasket sealing ring is damaged, you can get water into the cylinder. Also, check both heads to be sure they are absolutely flat-they can warp if overheated. If the head gasket sealing ring is intact, you can get water from a leak in the exhaust chest. A leak in the exhaust chest can be from a bad manifold gasket, (on a bubble back: can be from an overheat- warping the exhaust filler blocks-causing misalignment,) or from casting porosity in the inner exhaust manifold. The water pressure from the cooling system is enough to force water into the exhaust cavity. Exhaust chest leaks tend to affect the lower cylinders. Head gaskets should be retorqued after the engine goes through 2-3 heat/cool cycles. Ditto for the exhaust covers. You should be able to pull the exhaust cover and inner manifold off without removing the powerhead. If you put the inner exhaust manifold on a level surface, you can layer some water on it to check for porosity-also hold it up to a light source.

 

[oldcatamount]

Re: Water in the crankcase questions? 115 Johnson crossflow

My bet is that when you did the re-build you probably didn't re-surface the head/s. Take the heads off and put them on a flat surface (like a piece of glass) with some 400 grit wet/dry emery paper. With even pressure, move them in a figure 8 pattern until you get the entire surface flat and shiny. Also, some head gaskets require a sealer and some don't. Be sure you look at the new gaskets as they will be stamped "no sealer" if they don't require it. Also, water in the crankcase won't drain out, it will be blown out with the exhaust.

 

[GatorMike]

Re: Water in the crankcase questions? 115 Johnson crossflow

What year is this?

It is a 98 115SPL Bubble back Model #J115TSLECM

If the head gasket doesn't do it I expect the problem may be porpsity in the exhause manifold. When I had it apart I noticed the manifold had a lot of pits. None of them were deep enough to go all the way through it but I'm starting to wish I had replaced it anyway. I know that is a pretty expensive part and if I have to replace it I will probably look for a salvaged one.

 

[emdsapmgr]

Re: Water in the crankcase questions? 115 Johnson crossflow

If you can determine which of those manifold pits actually leak water, you may be able to have it aluminum welded in those leaking areas. That type of welding does not involve a lot of heat, so the exhaust manifold probably won't warp. Just find a shop that does aluminum welding. Those were common manifolds, so you may be able to locate a used one somewhere. New ones (323468) are over $ 400.

 

[Haffiman]

Re: Water in the crankcase questions? 115 Johnson crossflow

Pull the heads.
Check for cracks in the aluminum surrounding the steel cylinder sleeves.
If damaged and poor sealing surface on top, water may seep in between the aluminum and sleeve and if really unlucky get down to the intake ports area.