HydroLocking 383 mercruiser

[stinger222]

Starters keep taking teeth off my flywheel...Replaced flywheel ring gear, replaced starter, 3 boat trips later, same thing, that awful sound from the starter...mech told me to pull spark plugs and check for water...none until #6 cylinder, water came pouring out!!! No water in any other cyl though. The exhaust man on that #6 side had a crack in it because the idiot I bought the boat from forgot to drain it winter before last, so I had it welded..only crack we could see was on the outside..we pressure tested it and it was fine...guess I should have just replaced it....my question is, I have rotated the engine by hand past the broken tooth...if I get the boat started again, can I idle it around the marina to the ramp to get it out for svc or should I not run it until I get it fixed...I'm guessing when the engine is running, water can't leak into the cylinder since the exhaust would push it out...correct?

 

[87 bayliner]

Re: HydroLocking 383 mercruiser

i d say the starter issue relates to improperly shimmed starter. get it running and pull it out of the lake. you probably wont hurt any thing in the short term. if you are really concerned, pull the spark plug out before you start it. ( get ready for a loud exhaust like noise as the compression from that cylinder shoots out the hole. plus a really rough idle. ( :

 

[stinger222]

Re: HydroLocking 383 mercruiser

I thought the starter issue was shimming or starter itself, but I've used 2 different starters now, a Visteon marine, and an ARCO marine...never have had to shim starters on this engine before. If it was a shimming issue, the noise would start from the get go, but upon initial install of both starters they fired up fine with no noises...Then after a few lake trips followed by the boat sitting for a week or so, the problems started...now I know why...water leaking into the#6 cyl. Hi torque starter trying to crank engine with water in a cyl...broken teeth on flywheel. You can feel the missing tooth.

 

[Don S]

Re: HydroLocking 383 mercruiser

Mercruiser nor Volvo in modern times (1970 to date) have EVER used shims on the starter. So that is not likely to be a problem. Besides, water in the cylinders will not be cured by some starter shim.

When a block cracks, you really need to do a cooling system pressure check to make sure the inside isn't leaking into a cylinder or the crankcase where you can't see.
It could also be a manifold, risier, or gasket/surface between the two that has failed and allows water into that cylinder when stopped. The valves on that cylinder are probably open which is why it gets the water first.

 

[stinger222]

Re: HydroLocking 383 mercruiser

Got the boat running, ran great, put it on the trailer and brought it home. Pulled sp plugs, no water. pulld exh man, hooked it to garden hose, no water going into exh runners??? scratching my head on this one. No water in oil at all. The man did have an external crack in it that I had repaired 2 seasons ago. Maybe internal crack that expands when it man gets hot and lets water in???? I have silent choice exhaust..

 

[Bondo]

Re: HydroLocking 383 mercruiser

Maybe internal crack that expands when it man gets hot and lets water in????

I'd replace it,+ Try again.......

 

[stinger222]

Re: HydroLocking 383 mercruiser

I spoke too soon, drained the oil, there was a little water in it. Wouldn't some water get in to the crankcase if water has been leaking into my exhaust manifolds into the cylinders and I've been driving it like this for 2 seasons???? I'm just hopeful my problem is the water coming in from a bad riser gasket (gasket was very brittle) and not cracked cyl head or block....the amt of water that came rushing out of the #6 was overwhelming...leads me to believe exh man/riser/gasket issue...but what about the slight amt of water in the oil??

 

[95yj]

Re: HydroLocking 383 mercruiser

Screwing around with bad exhaust can gernade your motor. Water on top of the pistons while running can produce chucks of shrapnel out of the piston tops. Hydrolocking cylinders can bend rods. Seriously look at replacing your manifolds and risers unless you want to replace your engine instead. Afterwards, you'll still need a new exhaust or you'll do the same thing to the next motor.

The little water in your oil probably drained past the rings in cylinder #6. Since you have to pull the motor to change the flywheel, you might want to pressure check the heads and block for cracks since you know the motor froze once. Hopefully the motor was drained and there was just water left in the exhaust when it froze.

 

[stinger222]

Re: HydroLocking 383 mercruiser

Pulled spark plugs again after driving the boat around marina to the ramp...guess what, water came out of #6 cyl again...but none of the other cylinders...if water was coming in through exhaust, wouldn't it be in a few other cylinders on that side...When I pulled exh man there was no water in the ports! Might be a cracked head or blown head gasket??

 

[captdre]

Re: HydroLocking 383 mercruiser

Could be the head gasket if it's ruined between a waterjacket and your #6, but you'd have a rough idle do to lower compression on that cylinder, do a compression check. If #6 is lower than the rest, that could be your problem.

 

[stinger222]

Re: HydroLocking 383 mercruiser

pulled off the head, no cracks that I can see!!! #6 is full of water on top of the piston, other cyl have no signs of water. I don't know what a blown gasket looks like so I can't tell. This is really frustrating. rotated engine so I could look at #6 cyl walls, no cracks at all.

 

[stinger222]

Re: HydroLocking 383 mercruiser

Engine idled fine, ran great, i think the water is only getting in after shutdown. Exh manifolds were dry I think I will replace head gasket and bolt it all back together and give it another whirl!!! Since I took the head off, I mine as well buy some new hi-perf heads...

 

[stinger222]

Re: HydroLocking 383 mercruiser

Pulled head, no cracks that I can see, head gasket looks good. Water has to be coming in from riser/manif gasket...just wonder why water is consistently in #6 cyl..maybe its just luck that is the path the water always takes after shutdown...anyone else ever seen this, water going to one cylinder like this.

Going to slap on new riser gaskets and try it in the driveway on the muffs and run it for awhile and cross my fingers.

 

[Reel Poor]

Re: HydroLocking 383 mercruiser

If the manifold cracked on the outside from freezing it's probably damaged on the inside also. Why wouldn't you replace them? You seem to believe the manifolds/risers are a source of the water. Manifolds are parts that require replacement for preventive maintenance anyway.

 

[stinger222]

Re: HydroLocking 383 mercruiser

If the manifold cracked on the outside from freezing it's probably damaged on the inside also. Why wouldn't you replace them? You seem to believe the manifolds/risers are a source of the water. Manifolds are parts that require replacement for preventive maintenance anyway.

Why not replace the manifolds right now? 2 reasons: a. I ran the boat all last season after the manifold was welded up with no problems and when you look inside with a flashlight I just can see any cracks or holes b. I'm also "reel" poor right now (recent divorce) and a decent set of alum manif and risers is going to cost me over $1000. I agree with you that is probably good preventative maint. I'll run it in the driveway with the garden hose with new riser gaskets, then pull #6 sp plug and if no water, problem solved...Get new manifolds next year.

 

[alaska_av8r]

Re: HydroLocking 383 mercruiser

FWIW....I have been dealing with a water issue similar.....it turned out my exhaust riser had an internal crack....in my case it kept dumping water into two of my cylinders....the same two......the reason being......when I stopped my engine, those two cylinders ended up with the exhaust valves open and the water never made it through the manifold past them.....

Don't know if that will help you...but I also agree if you had an external crack in the exhause.....odds are you probably have an internal one as well....

good luck......

 

[95yj]

Re: HydroLocking 383 mercruiser

Replacing a bad manifold costs a lot less than replacing an engine.

This is what pistons look like when they get wet while the motor is running:

 

[stinger222]

Re: HydroLocking 383 mercruiser

replaced riser gaskets, ran boat all day on the lake, pulled spark plugs, no water. problem solved...

 

[stinger222]

Re: HydroLocking 383 mercruiser

spoke too soon again!!! Went down to the marina today to pickup stuff I left on the boat. Decided to pull #6 sp plug again to check...a little water came out....I replaced riser gaskets and head gasket. Pulled the other 7 spark plugs, no water at all. This is driving me nuts. The head looked fine when I pulled it off to check it, no cracks I could see, same with the manifold. Maybe it is the risers. I ran it on the muffs at home sat night and pulled the sp plug sund morn and no water. Then we ran it all day sunday, ran like a champ. I leave it in the water in my slip over night, and next day, boom, water in #6.

 

[FreeBeeTony]

Re: HydroLocking 383 mercruiser

Maybe the boat is on a different angle when on the trailer as compared to when in the water causing the water only to enter the engine when in the water?.........Just a thought.