MilkShaker 4.3L Mercruiser 1998

[ibrw1]

I started last week working on neighbors milkshaker. Cleaned out oil/water, put in new oil, ran in driveway with the flush muffs. 30 minutes. Checked oil. Looked great, no shake. Went on river for over 1/2 hour, got home, checked oil, no shake, level perfect. Next trip, Went on river 5 minutes, engine foaming all over.
Did compression test. All within 10 percent. No signs of water in cylinders, although there may have been. I do not know history of boat. I want to pull heads as a start, best guess, am I making mistake? What is procedure? I am almost positive that the block is good, the head gasket is bad. The engine would not start when he got it. He sprayed an entire can of ether down the carb running and goosing the engine. Bad fuel pump. Anyway ether is good if you leave it in the can.
So, what's up? Right track?

 

[Rick Stephens]

I've been thinking on this. No answer really without a tear down and you actually see where it is coming from, but most common crack in a 4.3L is first along top the lifters in the valley, and second in the heads. These are the weak spots if frozen. If hydrolocked I'd expect the heads to be the weak spot. Running on ether would be over pressuring damage like a hydrolock, is my guess. Head gasket, maybe. More likely a cracked head.

I think first I would pop the risers off and cap the top of the manifolds. Then pressure test the cooling system and see of you can hear anything. After that i'd surely pull both heads and have them magnafluxed.

 

[ibrw1]

Ripped engine apart, spun number 1, took heads and block in for magna-flux. No cracks no leaks no issues. We read stores HORROR STORIES where guy checked everything, as we did, rebuilt and pow, right in the pants. Milkshake, bent rods. My buddy is replacing exhaust manifolds and risers with brand new. Ok, what am I missing? Heads, block, risers, exhaust manifolds, even checked intake. If anyone has ideas, even off the wall grasping at straws, voodoo crazy female premonitions. Bring em on. Thanks everyone.
I saw some rust in exhaust manifold port associated with number 1. Sorta. If cylinder had hydro lock, well yes, how could it not.

 

[ibrw1]

P.s. His flappers, they were warn out. It seemed obvious to both of us, port was much different than starboard.

 

[alldodge]

My guess is he may have a crack in the cylinder wall.

He sprayed an entire can of ether down the carb running and goosing the engine

Took it out for a 30 minute run, shut it down all good, oil clean (engine is up to temp). Motor sits and slowly starts leaking water into the pan. Take it back out and 5 minutes later you have foam from the water that leaked

 

[Bt Doctur]

what you will need to do is remove the heads, wipe each bore dry, refill block with water up to the head bolt holes. rotate each piston to the bottom of its bore
and wait 5 minutes to see water leakage. Do the same for each bore. Positive you will find a cracked wall. Most times you will feel it with your fingernail.
Closely inspect the head gaskets for any damage. Was this motor worked on prior to the original trouble? Incorrect assembly?
Without water in the bores the crack can be below the ring area at the bottom of the stroke, intake gasket, crack in the area under the thermostat,

 

[ibrw1]

Machine shop gave a-ok on heads and block. Engine is in a 100 pieces. I love the poor mans pressure test! Wish I've waited for your response. Machine shop says no leaks. I couldn't see or feel anything. You think that I should continue to keep testing block/heads? Also, let's say that I got a new engine, new manifolds and risers. Anything left out. I'm only looking for in addition to more testing, what else may be at fault. Thanks

 

[alldodge]

My next WAG would be the intake manifold

Edit: what method did the machine shop use to test the block?

 

[thumpar]

The intake manifold gasket is a weak spot on these engines. I have had 2 go on the 4.3l's

 

[Bt Doctur]

Did anybody work on this engine prior to failure? Was there any sealant at the water ports for the intake maifold?
Have the pistons been removed yet? Sitting on some wood blocks you can still fill the block and see if any water drips from
the bottom of the block

 

[flipbro]

Had the same problem. Turned out to be bad manifold to riser gaskets.

 

[Faztbullet]

I have had 2 that customers self winterized and the bottom of the intakes where cracked......

 

[Rick Stephens]

I have had 2 that customers self winterized and the bottom of the intakes where cracked......

Really! Wow, never thought of that. Is there any special step required to prevent leaving water there?

 

[Faztbullet]

Really! Wow, never thought of that. Is there any special step required to prevent leaving water there?

I myself jack the front of boat up so motor is not level and backflush it with gallon pink antifreeze and in a houseboat I drain and fill motor with -100 polypropylene

 

[alldodge]

The 4.3 intake is a shorter version of the 5.0/5.7 and the water should flow right out when the block plugs are pulled. What is keeping water in there with the 4.3?

 

[dpoff]

The OP said that the "flappers were bad". (post#4) That would be my guess. He went out for a half hr run, no problems. Then a five minute run with problems. Maybe the second outing had the boat go off the trailer faster or used reverse gear with a little extra throttle and ingested water?

 

[ibrw1]

Embarrassed to hell, intake failure at the head. Clear as day!!!!!!! Thanks everyone! You guys are the best. As always.

 

[alldodge]

Glad you found it, if it was a snake thing, I'll admit to missing the simple things my self

Hey you got the engine all checked and new again when it goes back together

 

[ibrw1]

Ok, update on 4.3 milk shaker. Changed exhaust flappers, risers and exhaust manifolds. Put engine back together. Runs great. No clue where water came from. Ran it all summer. No more leaking. I don't know method machine shop did to test heads and block. The machine shop we went to sent everything to another machine shop. I no longer trust anything this guy says. Paid 250.00. Took a month.

Got one last thing to fix.

Here's question. Engine starts, idles then dies. All of the wiring was jury rigged. I wired everything EXACTLY as Mercruiser recommends. Wire color codes, right connectors. Looks like factory original.

I figured out NUT JOB that owned boat before had jumper wire from fuel pump to ignition switch.

I jump to battery, runs great! I read about fuel pump oil pressure switch. I know for a freaking fact this engine does not have one. It has oil sending switch just like car engines have. Oil pressure gauge. It's my neighbors boat and he is very very very picky. Every bolt had to be painted Mercruiser black. 17 foot Regal, pumped 9500 in parts and labor into it. New gel coat, powder coat trailer, all new vinyl and carpet.

Beautiful boat. Just this one last issue. Ideas?

Thanks.

P.S.

Don't bother saying to tee off oil sending switch, or other non Mercruiser dealer approved method. Not gonna fly with Admiral Kirk.

 

[bman440440]

No Title

your oil sender should look like what in the pic... the arrow points to the "oil switch" and your system needs it to run... I have the exact same engine and your system should have all the components in that pic... I just rebuilt mine and got all new parts for that just because i'm anal too! here is the link to the parts schematic --->http://www.marinepartsplus.com/cata...plus_2_BBL._GM_262_V-6_1998/809969+98/2694-60