1980 75HP Johnson Seahorse - Water on Spark Plugs?

Zoob

Seaman
Joined
Apr 30, 2010
Messages
52
My Johnson (electric start) - last year started running rough, not wanting to start well. All summer long, she ran great - at the end of the year is when it started flaking out - run rough, take forever to "warm up" and at start - white puffy smoke initially.

I pulled the plugs, and noticed condensation / water drops on the plugs. So - I'm getting water into the pistons somehow. I noticed it in two of the three spark plugs.

Besides this rough-run when it warms up - it runs fine - isn't any louder than normal, and seems to be firing fine on all three cylinders.

Is there a way to determine if this is a cracked head or possibly just a bad gasket in the water jacket - or maybe something else entirely? The fact it runs OK once it's going, makes me want to think water jacket gasket - as I suspect I'd notice if there was a cracked head with all kinds of other nasty sounds or something...

Any advice would be appreciated.
-Z
 
D

DJ

Guest
Re: 1980 75HP Johnson Seahorse - Water on Spark Plugs?

Two places to look:

1. Head gasket. I would go ahead and replace it, checking for cracks. REMEMBER, the torque for head bolts is INCH pounds, NOT FOOT pounds.

2. The olther place is the side cover (exhaust housing) gasket. Same rules apply for torque.

Both jobs are simple.
 

Zoob

Seaman
Joined
Apr 30, 2010
Messages
52
Re: 1980 75HP Johnson Seahorse - Water on Spark Plugs?

Both gaskets replaced, works like a charm, runs great now - thanks a bunch.
 

mbarbian

Recruit
Joined
Sep 14, 2012
Messages
2
Re: 1980 75HP Johnson Seahorse - Water on Spark Plugs?

Hi,
New to the forum but found the help great.

I too have wet (water) plugs on a 1985 Johnson 15. I have changed out the fuel so I don't think it's coming from there.

I'm up for replacing the gaskets referenced above but I'm not sure which ones. My choices are:

GASKET, Water cover (Seem like this one for sure)
GASKET, By-pass cover (I don't know what this one does)
GASKET, Thermostat (dont know)
GASKET, Cylinder head (seems like this one)
GASKET, Exhaust cover (Don't know)
POWERHEAD GASKET SET (Seems like more than I need)

Thanks for the help.
Mark
 

Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: 1980 75HP Johnson Seahorse - Water on Spark Plugs?

mbarbian, you should start a new thread so that you woun't get lost mixed in with another post.
The place I would start would be the head gasket, easiest to replace. The exhaust cover gasket could also allow water into the engine, but it is a lot harder to replace.
 
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