Houston, I think we have a problem... *updated with a resolution!*
 

Looks like the launch of the new boat may be delayed a bit. I was going through the boat today, and one of the things I did was check the oil.

Starboard engine is fine, right on the full mark. Port engine, however, is another story. The dipstick shows well above full, and the oil is a lighter brown, chocolate milk color. Looks to me like I've got oil in the water on the port side.

Now that being the case, both motors have started and run fine on the hose. Obviously, I won't be starting the port motor again until I can change the oil, but can I get some ideas on A) what could cause water to get in there, B) how to fix A, and C) what sort of damage may have occurred up until now (hopefully none!).

Many thanks - I had forgotten just how much fun a boat can be... :rolleyes:

Re: Houston, I think we have a problem...
 

Exhaust manifold leak

Intake manifold and or gasket leaking

Pull the thermostat housing and look for a hole under the t-stat.

Re: Houston, I think we have a problem...
 

Worst case,cracked block from freeze? Prob just head gasket or intake gasket leak,,intake more common and the place to start. Doubt you did damage by running that way a little,,,until it gets really milky it's mostly oil. Have heard bad reversion can do this over time. Can you pull the distrib and pressure up your water jackets and peak in the intake to look for a drip. Might could borrow a scope?if it's not coming from the valley pull the heads next and look for gasket failure,,if not t(here,,,do all your plugs look good?no water?)block is cracked? My .02 Good luck. Guess your heads could be cracked or corroded thru as well.

Re: Houston, I think we have a problem...
 

I had the exact same problem once. Ended up being Exhaust Riser Gasket. If you had a crack it will fill the crankcase with water fast. LIke stated in a prev post, it only takes a little water to make milkshake. I found my problem by taking off the ebow on top of the exhaust and you could see where the water was dripping back into the exhaust.
Good Luck, better now than the middle of summer :D

Re: Houston, I think we have a problem...
 

Hey Dock,
It would be a real good idea to get that oil out of there pronto and change it before it does any damage. Do it with cheap oil because you will be doing it again as soon as you find the problem and fix it! ;)

Trust me on this, I've been there!!!!


Craig

Re: Houston, I think we have a problem...
 

I'm betting it's an exhaust gasket - I have had a feeling that something ain't quite right on that side. That being the case, I'm nowhere near a mechanical guru, I'm wondering if I should just shop this out...

Re: Houston, I think we have a problem...
 

That sux! I just bought a boat this winter and lost a motor on it's maiden voyage. Mechanic has it now doing a complete rebuild :( dropped a valve and blew it out the motor) Sounds like you might get it fixed for hundreds instead of thousands. Good Luck

Re: Houston, I think we have a problem...
 

OK boys, I just looked under the hatch. There's this big black hunk of metal, with gizmos and widget bolted all over it. Says "Mercruiser" on it. Which thingamabob should I unhook first?

In all seriousness, I'm not that clueless, but close. I'm willing to have a go at this, and I'll even document it - maybe we could sticky a thread or something for other noobs like me.

Re: Houston, I think we have a problem...
 

Now for some visual aids.

The guilty party (or the victim, depending on how you look at it) - a 1996 7.4 LX MPI, approximately 400 hours.

Re: Houston, I think we have a problem...
 

Next question, I can see where the exhaust risers (or elbows) attach to the manifolds. Should I take these off? And if so, what should I be looking for?

Also, this gizmo blocks one of the four bolts holding the elbow in place. What is it, and any suggestions on how to reach that bolt?

Re: Houston, I think we have a problem...
 

Last one for now - what is this linkage? I thought it had something to do with the Silent Choice exhaust, but it looks like there is another linkage back on the Y pipe that should control the exhaust. So what is this doohickey? Both motors have this stuff...

Re: Houston, I think we have a problem...
 

The linkage on the starboard exhaust riser is your Bravo gear shift. Check both exhaust riser gaskets on that motor. It would be a good idea if that proves to be the problem to change them on the other motor also as a preventive measure. Remember the gaskets may look OK but the riser or manifold could be corroded enough to allow leakage. Good luck.

Re: Houston, I think we have a problem...
 

Am I to assume that the riser gasket is between the manifold and the riser? As opposed to the exhaust gasket which is between the manifold and the head (learnin' something new every day!)

Re: Houston, I think we have a problem...
 

The gasket between the manifold and the head can not make milk shake. The one between the elbow and the manifold has a water jacket and an exhuast passage in it. I got some bad news though. Most of the time if that gasket has let enough water in to make milkshake, the valves are already screwed. How long did you let the engine idle on the hose? Merc actually doesn't recomend running the engine below 1200RPM on the hose becuase if you have high water pressure at the hose it can cuase reversion. I have only ever seen it happen 3 times but it is a possibility. The elsows that you have on that motor are the old bottom flange SS elbows and are were a very poor design. they are tottaly interchangable with the new cast iron top flange elbows wich work a whole lot better. I would recomend replaceing them with new ones on both engines. IF the milshake was cuased by reversion from ideling on the hose all you need to do is flush the crankase and you bcak in buissness. You will have to change the oil a few times to get it all out . They also sell an engine flush at NAPA that after the first drain you substitute for one of the quarts of the oil. The stuff works great but I think all it realy is Diesel fuel. It ussually takes 3 or 4 oil changes to get it all out and I like to change the filter every other time during the flushing process. Good luck and I hope I was of some help.

Re: Houston, I think we have a problem...
 

Oh and the dookicky you pointed to, the black metal box looking thing, is the ECM housing. The top folds open, its sometimes held down by a wingnut on either end that you just need to loosen not remove to get it open. Once you get it open you will see 3 nuts that hold it to the elbow(there are 3 studs in the side of the elbow) take them off and flop it out of the way. Same goes for the shift bracket, 3 nuts, just have a look at it and only take out the 3 that hold it on, they are recessed. you don't need to take the rest of them off that hold the throws on the shift bracket. Leave the cables attached and don't mess with them or you will mess up the shift adjustment and ou have to pull the drive and use some specialty tool to set it correctly.

Re: Houston, I think we have a problem...
 

Ya good idea ..replace one quart with kerosene or diesel.. run it a couple hours ..change it again till its clean.

Re: Houston, I think we have a problem...
 

I would't run it any longer then it takes to put some heat in the oil and I also woudln't rev it higher then 2000 or so, a quart of diesel will thin the oil alot more then you think.

Re: Houston, I think we have a problem...
 

Done it a hundred times in cars with noisy lifters ..It cleans out the sludge pretty well.. You have to get it hot and run it through the oil passages to do any good IMHO Tranny fluid works well too

Re: Houston, I think we have a problem...
 

It could very well be reversion from high water pressure. My neighbor came over to take a look when I fired her up, and he did turn the hose up while he was standing there (just trying to be helpful).

Maybe I need to change the oil and see what happens before I start pulling things apart. Any suggestions on oil-change gizmos? I had the 5 gallon bucket / 12v pump set up, but lent it to someone and haven't seen it since. Wondering if that is right way to go.

Thanks guys, this is all new to me (my last boat was brand spankin' new, this one is almost 9 years old). This is why OSO is a bargain!

Re: Houston, I think we have a problem...
 

I get emulsified oil out using half and half oil/diesel mixture run through the engine for about three minutes at idle. That usually cuts all the emulsified oil out. I then fill with cheap oil just to check and run it. If I don't get anymore emulsified oil, I drain it and put in good oil. Running the diesel won't hurt the engine, diesel has a lot of lubricating qualities.

Re: Houston, I think we have a problem...
 

Dock, did you check the oil before you bought the boat?

Re: Houston, I think we have a problem...
 

How can the hose cause reverson.That's more with big cam overlap and long idle and would show up more when you pull the heads and will find the valve seats have a dusting of rust .I run on any hose shop or at home full on and never show more than 10lb. at the oil cooler.

Re: Houston, I think we have a problem...
 

If you check raw water pressure at idle in the water it is between 2 and 5 PSI. 10 is too much at idle. The exhuast isn't making enough pressure at idle to hold it back and you wind up with water in the clyinders and then the crankcase.

Dockroacker, I would also recomend pulling the pluga and cranking the motor for a while to puch all the water out of the cylinders if any has gotten there and then spray some oil in each cylinder. WD-40 is fine. You will want to do this stuff fairly soon before the water has a chance to pit the clyinder walls and valves.

Re: Houston, I think we have a problem...
 

ditto

Re: Houston, I think we have a problem...
 

lotsa pics here to help you tear it down.

http://www.mercruiserparts.com/selec..._nbr=809994965

Re: Houston, I think we have a problem...
 

Positive displacement pump , nothing you can do to adjust pressure..more pressure on the inlet side should not effect the outlet side.

Re: Houston, I think we have a problem...
 

Theoretically positive displacment in a perfect world. If you turn the hose on but don't start the engine water comes out the exhuast after a while. We installed a reman 502 from Merc in a boat last year. After 20 minuits or so of ideling we found milkshake in the oil. Called Merc and they said don't run on the hose under 1200RPM for more then a few seconds. I argued with the guy on the tech line for 2 hours saying the same thing you are. He insisted that I flush the crankcase and see what happens. No problems after that. Can idle all you want in the water but not on the hose. Boat as had no problems since.

Re: Houston, I think we have a problem...
 

Im not doubting your results ..I just cant see it without some other problem..Water always leaves after the elbow ..unless you have waves rushing up the pipes..
Although water is coming out the hose at 40-70 psi. So I guess :(

Re: Houston, I think we have a problem...
 

It's a rare occurnace and according to merc it is most common when the exhuast hoses are level or have very little downward slope wich makes sense. Just not enough exhuast pressure at idle to clear the excess water that is moving past the seawater pump due to excessive hose pressure. That was their splaining anyway

Re: Houston, I think we have a problem...
 

If it was from too much inlet pressure at idle causing reversion AND he has test ran both motors wouldn't they both be contaminated? I believe its possible but i expect something worse,Smitty

Re: Houston, I think we have a problem...
 

Not necessaraly, it he ran one motor significanly longer then the other then you may not see the problem on the other one. I'm not saying that this IS the problem, I was poining out a possibility. And no I don't spell very well :D

Re: Houston, I think we have a problem...
 

Dock,
Did you get the "milkshake" oil out of there yet? If you haven't, you need to do that asap!!

Re: Houston, I think we have a problem...
 

Ok that actually make a little sence, i can see how that can happen ..In that case id be reving the motors while on the hose to blow the excess water out..

Re: Houston, I think we have a problem...
 

If it were mine before the last quart of oil was drained out of the problem motor I would have allready had the engine and exhaust isolated and the block checked for holding air pressure at least 20lb. for at least 10 min.Those stock motors I still feel will run all day on or off the hose with out reversion I have a LSA of 110 and installed on a 110 and I did the valves last year only had a small amount of rust on the valve seat and run on the hose every two weeks.I would be looking at intake area Mer.service bulliten has a different tighten sequince for intake manifold on bbc because of this and I had problems that there was no thread sealer on the intake bolts that went through the block but that only gave my a small amount of water that showed up as lots of steam out of the valve cover breather.I don't think my 10lb is to much pressure at idle when the hose is at 60lb at the shop.Your talking with the boat in the water and sucking up the water yes 10 lb. would be to much as at higher rpm we would be over our let's say between 18 20lb. at WOT. I think Mer was talking about there higher perf. motors. Good point Articfriends.Not the hose in this case.

Re: Houston, I think we have a problem...
 

Here we go ... problem is .. it could be any of the Sineros mentioned ... When i got my 311 last year ..same thing happened first time out ..water in port motor ...we pulled the motor ..pulled heads ...had heads checked and valves done ...pressure tested manifolds .... never found a problem ...put it all back together and it runs great.... It does use oil like a mofo but thats another Thread ... :rolleyes:

First thing is to get the oil out .. Cuda's half n half should do it ....oil cylinders like Hillbilly sez ... if I pulled anything it would be the risers and look for any signs of water running back towards motor .. also compression test the motor ...but you need to have the water out and not have just oiled the cylinders ...that gives funky readings ... how old are the EM's and risers ? If they have 400 hours ..they prob should be changed out ...but in the photos they look pretty good ..outside ...cant tell inside but usually if you see any signs of water on the outside at the risers and minifold joints its time ...

Re: Houston, I think we have a problem...
 

The manifolds and risers look fine on the outside - no signs of water or rust anywhere. They definitely the originals, there is no indication that a wrench has ever been on them since they left the factory in OK.

I'm going to start with the risers, and if that doesn't do it I may take it to one of the local shops.

Re: Houston, I think we have a problem...
 

Well hell I was wrong got 5-6lb.at the cooler (my son got me straight on that )and I got the pressure from the hose and it was 90 psi at my house.I feel so silly. Hay Dock I still think if you take off one therm housing hoses that leads to one manifold then take off the hose at the outher end of the outher manifold and double it back on it self and hook it to the therm housing it will make a loop and that seals off the motor.then take off the raw water hose from the therm.housing.get a pice of hose that will fit the therm housing at auto parts store and a water pressure gage and air chuck adapter and pvc fitting from home depot and just charge up your block you might be able to disallow the block with out to much tearing down first.Hope you get it fixed. James

Re: Houston, I think we have a problem...
 

I was ready to hop on the "there's no way the hose pressure can cause reversion", and I still might. But in looking at your pics, it seems like your exhaust doesn't drop much at all and with the silent choice, water is probably dumped into the exhaust fairly high up close to the elbow. In your other boat pics, I noticed that you're backed into the driveway. Is there any slope there? The boat will sit a lot lower in the back in the water than it does on the trailer, and if the boat is pitched down at the bow, that only makes it worse.

I had some reversion last year from a low idle and a low pitch to my exhaust on 500's, and it dumped water probably 12 inches farther down the tailpipes than your setup.

I'd change out the oil, crank up the trailer jack, and run it for a few minutes at 1200 rpm before pulling the risers. If you see water in the exhaust manifold, it would most likely be from the riser gasket, which you'll be replacing anyway when you put it back on. If it's dry, it was probably reversion. If the oil gets milky again, then it's probably something else.

As for changing the oil, I use the big bucket with the electric pump on it. Check your drain plug to see if you have the merc oil drain system that has a hose threaded into the oil pan.

Re: Houston, I think we have a problem...
 

Doc,,,,,, you never said IF you checked the oil when you bought the boat ??????? I too agree,,, you have a very shallow slope in the exhaust and the hose could have been the problem,, I would change the oil, run it at the ramp and see if you get any water..

Re: Houston, I think we have a problem...
 

Mike it wont hurt to change the riser gaskets for piece of mind, mine looked like brand new on the outside and they were shot! I lost a motor before I figured it out.