Mercruiser 165 HELP!

[Jono]

1974 Stamas, 165hp mercruiser. Recently spewed an oil water mix from the vent hose on the rocker cover. Got a complete head and valve job done. First time out it happened again.<br />Here's the problem. The motor still runs perfectly. The plugs are spotless. The temp remains constant. No sign of anything in the wake.But the crankcase is full to the neck with this mixture. Where can the water be getting in?????

 

[capercanuck]

Re: Mercruiser 165 HELP!

I just went through a very similar situation. I had a cracked manifold. On top of that my head gasket was split between two of the cylinders, what a mess. I had to change the block, manifold, rebuild the head and replace the riser. This fixed the problem. I think if you have a split block the water/oil mixture will also show up. Someone told me they had a split block and when apart there was no split to be seen, but when under load and hot the split would open and allow sea water into the cylinders. Any good marine mechanic should be able to recognize these problems fairly quickly. Also, if it is your block, you can purchase a good used chev block, change the frost plugs and bearings, and it will work fine. Once you price a new block you'll see why it's more advantageous to look for used. Godd luck, and keep us posted!

 

[Jono]

Re: Mercruiser 165 HELP!

Thanks Capercanuck. Very much appreciated. Now I'm praying its just the manifold! I will let you know the outcome.<br />Any ideas as to what to use to flush out the engine. This stuff is like soft concrete!

 

[Trent]

Re: Mercruiser 165 HELP!

Have the manafold and the riser pressure checked. Somtimes the problem is a faulty gasket on the riser or manafold. But if they are orginal equipment, Just go ahead and replace them.

 

[flashback]

Re: Mercruiser 165 HELP!

Jono, look at it logical, there are many areas of the engine where water can mix with the oil. so process of elimination is the best route. start with the least expensive and work your way up. also past history of the vessel is helpful. was it winterized last winter? I know the most common thing around here is folks buy a boat from a sales rep that does'nt know anything about a boat, consequently , they never realize that water in an engine block will freeze and crack the thing over the winter while it is sitting in the driveway. hopefully this has not happened to you. on the other hand It may be something simple. although simple is relative