1985 Inboard 3.8 Mercury V6

[85merccruiser]

There is water coming in the cylinders, only on right side of engine,#2,4 and 6 cylinders. Boat works excellent while operating. But... when boat is left sitting for awhile, water somehow enters the cylinders and then when you try to start it, the engine acts like it is seized. if you remove the 3 spark plugs and blow the water out, the engine will work great again. What could possibly be the problem?

 

[greentahoe]

Re: 1985 Inboard 3.8 Mercury V6

Sounds like you've got a leak in the exhaust manifold, or possibly in the head. If the manifolds have never been changed then that's what I'd look at first. If you find that one is bad, then the other one is not far behind. You should be able to remove the manifold and pressure test it with air to see if there is a leak in it. If your engine is not fresh water cooled it could have corrosion from raw water cooling that has eaten through some place in the head. I've been through this with a 3.8 OMC. Good luck.

 

[Reel Poor]

Re: 1985 Inboard 3.8 Mercury V6

Welcom to iboats guys.<br /><br />greentahoe is spot on.<br /><br />I would have the manifolds pressure tested and if one is bad, replace both manifolds and risers. Dont let any water sit in the cylinders. Make sure you blow it out and put some oil in them. Also you should also change the thermostat and raw water pump.<br /><br />Be sure to change your oil also, there may be water in it.

 

[whywhyzed]

Re: 1985 Inboard 3.8 Mercury V6

ditto - don't keep running it like that. If you do, that water will lock your engine and you'll bend a con rod witht the torque of the starter - if you haven't already...

 

[KaGee]

Re: 1985 Inboard 3.8 Mercury V6

Just went through that with my 3.8 on the opposite bank. Replace the manifold. Water is leaking out of the jacket when sitting. <br /><br />Drain that manifold before it really seizes that engine.