engine problems

[maddog2]

I just spent $2,700. on a "remanufactured" long block Mercruiser 4.3LX V-6.
(1992) model. Apparently the intake was leaking and water mixed into the oil. I just drained 6 quarts of warm "Milk" from the oil pan.
It was on the water for about 15 minutes while going through the listed break in procedure from the mercruiser manual. I stopped in the lake, turned off the engine and restarted...then a loud pop. The engine started backfiring through the carb and was running rough. I got her back to shore and took her back to the mechanic.
We removed the intake and found that the last pushrod on the right hand side was loose and I believe the rocker arm may have broke.

The intake looked fine, it was removed from the old engine, cleaned in a professional parts washer and gaskets material was removed from the intake mating surfaces.
I was told by the mechanic to take it to a machine shop to pressure test for cracks or leaks....

Is there any other way that water may have entered the oil?, especially since the rocker arm and pushrod issue.

any input would be greatly appreciated.
James in NC
High Rock Lake-----

 

[HT32BSX115]

Re: engine problems

Howdy,


Not usually. You should pressure check the block and heads (before you remove the manifold) to see if you can identify where the leak is. Otherwise, water getting into the oil is usually from a cracked/head/manifold and/or a head gasket or (intake) manifold gasket leak.

Since you have a "new" longblock the cracked casting thing might be unlikely (but I wouldn't rule it out) Did you replace the original engine due to freeze damage? If so your intake manifold may have a hairline crack in the water cross-over.


regards


Rick

 

[maddog2]

Re: engine problems

The engine was replaced due to a frozen and busted block and exhaust manifolds. It has new exhaust manifolds and a remanufactured block and heads. The intake was not checked for any hairline cracks, just cleaned and installed. I can assume that the issue with the pushrod may fall on the engine builder. I have a 1 year warranty on the internal parts. I do not know if the rocker arm is in fact broken. I haven't removed the valve cover yet.
Can the right hand valve cover be removed without removing the exhaust riser or manifold? It looks close.

 

[HT32BSX115]

Re: engine problems

Can the right hand valve cover be removed without removing the exhaust riser or manifold? It looks close.

Can't see it from here You'll just have to try and see if you can get it off.... But if you had a cracked block from freeze damage you may have a cracked intake manifold too....There's usually pooled water in the manifold where the t-stat goes...if there was enough there it may have cracked it. That might allow water to drop into the valley.

 

[maddog2]

Re: engine problems

I took the intake to a machine shop and it was put on a vaccum test to check the water intake section. The test was good. No leak or pressure loss from the thermostat section.
One thing that I noticed before the engine was replaced is that the exhaust was missing a baffle on the right hand side. Im not sure if thats what its called. It allows exhaust to escape and stops water from running back into the motor when the boat stops. This may be the reason for the water in the oil. It was fine on the hose, but didnt get water in the oil until it was out on the lake.
Would this have cause the problems with the pushrod or valves on the right side?

 

[HT32BSX115]

Re: engine problems

Don't know what you mean by a baffle.

You really cannot get a lot of water into the engine oil via the exhaust system because it has to go by the rings AND you'll have severe hydrolocking right after you shut it down.

Some will go by the rings but not very much.

By baffle you must mean the shutter in the exhaust Y-pipe? #6 below?

If its missing or damaged you should replace both of them. also if one is not there it's probably crammed down below restricting the exhaust which will REALLY kill power output.

Even so, you will not get a lOT of water in the oil from that source because it has to go by the rings......Did you hydrolock the engine?

 

[maddog2]

Re: engine problems

Don't know what you mean by a baffle.

You really cannot get a lot of water into the engine oil via the exhaust system because it has to go by the rings AND you'll have severe hydrolocking right after you shut it down.

Some will go by the rings but not very much.

By baffle you must mean the shutter in the exhaust Y-pipe? #6 below?

If its missing or damaged you should replace both of them. also if one is not there it's probably crammed down below restricting the exhaust which will REALLY kill power output.

Even so, you will not get a lOT of water in the oil from that source because it has to go by the rings......Did you hydrolock the engine?

Im not sure what is meant by hydrolocking the engine. How is this done and how can this be avoided??

 

[HT32BSX115]

Re: engine problems

You will know right away. when it "hydrolocks" a small amount water making back into the engine via an open exhaust valve after the engine shuts down.

When you go to crank it later, all the water is not purged out and the engine stops abruptly it almost sounds like a dead battery because the engine won't turn all the way over until the water is either purged out the exhaust valves or forced by the rings.

If you replaced the engine and you didn't replace the manifolds and risers, did you take the risers off the manifolds and inspect them and replace the riser gaskets?

How old are they? (the manifolds and risers)

 

[maddog2]

Re: engine problems

I believe that I did hydrolock the engine. While I was on the lake trying to follow the Mercruiser engine break in procedure, I turned off the engine and it was hard to start...just like a dead battery. It would eventually start. I cut it off and tried it again and it popped...probally when the pushrod, valve, rocker arm became loose.

I have new exhaust manifolds, but the risers are the existing ones. The boat repair shop tried to use the same manifold to riser gasket sets and had a leak on the left side, so they tried to seal them both with silicone. The right side is not leaking, but the left side is leaking.

 

[HT32BSX115]

Re: engine problems

The boat repair shop tried to use the same manifold to riser gasket sets and had a leak on the left side, so they tried to seal them both with silicone.

They re-used old riser gaskets?....on a new engine?


Hmm....you need a new shop. (and maybe a lawyer)

#1 the gaskets are not all that expensive.
#2 they're usually put on "dry"
#3 Unless your risers were "perfect" they should be replaced.

Risers are usually NOT damaged when the engine freezes bacause the water usually drains out of them when the engine is shut down.....

You need to get both risers off, inspect carefully, and get new gaskets.

The sealing surfaces should be flat and clean. The "good" gaskets are silvery and are installed dry.


Also inspect your pushrods. You may have a bent one....

 

[maddog2]

Re: engine problems

Before I purchased a remanufactured long block engine, I purchased two new exhaust manifolds and installed them on the old engine. I then realised that the block was cracked as well, so off came the new exhaust manifolds. The boat repair shop exchanged the old with the new, but I didnt have new riser gaskets for the new engine. They just used the gaskets that came off the new manifolds to risers. The gaskets leaked, so they applied silicone to each side, although the left side was still leaking and they told me to order a new one. It wasnt leaking too bad, so I took her out to the lake to see how she ran. That is when all the problems started.

 

[HT32BSX115]

Re: engine problems

Not good to have leaking riser gaskets (as you well know now) sorry that happened!

Just get new ones and seal everything up. Some gaskets can be used with "sealant". The "new" style (silvery coating) riser gaskets are suggested to go on dry though.

The surfaces MUST be clean and flat.

My 460 King Cobra did exactly the same thing for a summer before I pulled the engine. It was fairly worn out and would crank after a couple of trys.

The riser gaskets were leaking on both sides.

 

[Don S]

Re: engine problems

New engine, new manifolds, then reuse a riser gasket, and use old risers. ????

Receipt for disaster.

 

[ziggy]

Re: engine problems

man, that is a sad story to be sure... likely over gaskets... bummer.

this might be an interesting read for you regarding water ingestion..

http://www.boatfix.com/merc/Bullet/01/01_13.pdf

 

[Howard Sterndrive]

Re: engine problems

the loose pushrod typical symptom of a hydrolock. With a good battery, the starter motor is strong enough to drive the valve shut with the incompressible water in the cylinder. The valve and piston may have broken - as well as the rocker stud or rocker getting broken or pulled out of the head to make the pushrod loose.

p.s. In another thread, you said the longblock was $1300... but now $2700?

 

[starsnstripers]

Re: engine problems

The other 1400.00 was probably to the shop for installing used gaskets on a new engine!!! That was a good read Ziggy, Sorry for your trouble there but i think the shop that put your engine together is to blame. Something didn't seal (used gaskets) ? I'd have a chat with them boys. Well hope you get it straightened out. You now have a few things to check out. Replace your shutters in your exhaust while it's apart. good luck

 

[maddog2]

Re: engine problems

the loose pushrod typical symptom of a hydrolock. With a good battery, the starter motor is strong enough to drive the valve shut with the incompressible water in the cylinder. The valve and piston may have broken - as well as the rocker stud or rocker getting broken or pulled out of the head to make the pushrod loose.

p.s. In another thread, you said the longblock was $1300... but now $2700?

$1300 for long block, $150 for shipping, $1200 for labor, $50 for used prop.
total---$2700.
I sure hope that the valve and piston isnt broken. I can deal with a rocker arm or collapsed lifter. I borrowed $3000. to replace this engine and my first loan payment is due June 1st.

 

[HT32BSX115]

Re: engine problems

You might have a bent push rod. I doubt you have a broken piston....That might happen from a hydrolock due to water ingestion because the engine is turning fast when it happens. But cranking with a starter is less likely to break much. It sometimes sounds like a dead battery.

After you check the rockers and pushrods, get yourself a cheap compression check gage a do a quick check.

 

[cannonford57]

Re: engine problems

the thing that troubles me is that a marine tech,for lack of a better term,even though it might take 2 weeks to get a gasket from merc or bombbardier,ya can get it the next day at a napa store...

 

[maddog2]

Re: engine problems

I removed the valve cover today and found that the rocker arm nut was not tightened into the head completely. There was a quarter inch of thread showing. The pushrod and lifter and cam lobe appeared fine. I tightened the rocker arm down and turned the motor over and it worked properly. I dont know if I have bent valve or damaged piston. Could this have caused the valve to suck water into the engine?