ways water can enter cylinder?

[Gus Mortimer]

Well i just found one of those "clean" plugs with a little grey gunk on it. This is the same 1982 90L6. the cylinder will turn any plug I put in there this way. My question is what are the different ways water can enter the combustion chamber (this motor has sat around for 5 or 6 years). what are the common causes. <br /> I am wondering if the mud daubers I found every where else on this thing could have done someting to the exaust to cause it, like mud in the exaust baffle or something?? will pluged exaust cause this?

 

[achris]

Re: ways water can enter cylinder?

If the cylinder in question is the bottom one, then the lower crank seals will be suspect. Otherwise leaking inner exhaust cover gasket can allow water in. I once fixed one that had a hole in the water jacket right next to the exhaust port that was sucking heaps of water in. The inner exhaust cover on these engines is held down by about 25 bolts that have to be 'cemented' in, using Mercury's special epoxy, called Resi-weld. And the bolts torque to 150 in. Lbs AND NO MORE! Otherwise the cover distorts and, you guessed it, it leaks water.

 

[Gus Mortimer]

Re: ways water can enter cylinder?

It is the second up from bottom, or#5. and I dont think it is heaps of water but it is getting the plug wet. <br /> So when you say inner exhaust cover, do you mean the cylinder block to baffle plate gasket. I have the manual and am looking and looking but the discription of the cooling system is really not even there, just what you can piece together.<br /> Will I need to remove the "cylinder block cover water jacket" to get to the gasket you are talking about? or do you just mean the gaskets under the exhaust cover?

 

[achris]

Re: ways water can enter cylinder?

I am talking about the very inner cover inside the exhaust chamber, not the cylinder block cover (where the spark plugs go). You need to remove the powerhead to then remove the 2 'outer' exhaust covers. The inner one is about 1/3 the width of the other 2. When you get the outer covers off, look at the egdes of the inner cover gasket and you'll find the areas from the gasket to the exhaust ports to be 'washed' clean, indicating that the gasket is leaking. Be prepared to break a few bolts off in the process. While you have the powerhead off replace the lower crankshaft seals. So it ends up being a fairly involved job. This job, called 'seals and side plates' should usually be done every 5 to 7 years anyway on all outboards, except newer models with single piece castings. <br /><br />Chris.......