Smarty pants, I really could use your help! 350 Mag trouble SOLVED?? MAJOR UPDATE

212rowboat

Dang... Man.... So sorry .

Michael T

Very, very disappointing.

pistole

From poor running to hydrolocked?

Black_Diamond

Is it hydrolocked from coming off plane?  Or after shutdown?

Handymans342

Get a diesel boat geeezzz

Glassguy54

Oh, man....This is without a doubt the most harrowing narrative on this forum. Such a sad tale. Have you considered an exorcist? I think that boat is possessed by an evil spirit.

Wildboating

It shut down while stopped and idling out in the lake.  I didnt realize it shut off until i went to take off.  When i tried to restart it it was locked up.  

I was asking some people about that last night @Alswagg   I am going to be there when he opens this time.  Are they supposed to be the restricted flow gaskets?

I noticed when i picked the boat up from the shop dock the boat had a hard time starting on the starboard motor, almost like it would briefly stop cranking every few cycles. Could i have single cylinder that is leaking?  Where should i be looking, i am quickly losing faith in this merc certified shop and or mechanic.  When we pull the plugs tomorrow if water is in all cylinders then should i be looking at the flappers.   if it is only one cylinder then would you be looking at specific damage?

What all can cause a hydrolocked motor?   
Missing flapper
Cracked exhaust manifold 
blown head gasket 
cracked head

Black_Diamond

Wrong risers
cracked intake manifold

Wildboating

I did not realize water ran thought the intake manifold, but after some quick research it appears the T-stat housing is molded into the manifold.  

aero3113

Wildboating said:

How would a cracked intake manifold cause a hydrolocked motor?  There is no water running through intake manifold is there?

I know it car engines have antifreeze in the intake manifold, not sure how boat engine route the coolant/water.

rasbury

Is this under warranty for all this? My lord, I feel your pain rinker brother...cant imagine...

212rowboat

I would suspect bad torque job on the exhaust manifold reinstall.  A bolt may hold torque on a bench, but the test is after a heat cycle or two.  A bolt not properly stretched during torque will stretch when heat cycles, and it wont snap back as it cools.... Because it wasnt properly stretched to begin with.  I wager BD has greater insight on this than I do... 

My guess is if the intake manifold wasnt a problem before then it's likely not a problem now either... Unless its been off.  Then torque is a player there too. 

This is almost a certainty something on the exhaust side of the head based on what you've shared recently.    

Wildboating

Cylinders 2-8 were flooded with water again.   The shop has no idea, we are 4 exhaust manifolds cracked.   The mechanic suspects it is cracking at higher rpm but has no idea why.    

I just talked to some other guys i know and one of them mentioned that he believes that these motors (350 mag mpi) routes water to one side of motor when thermostat is closed.  He questioned if that thermostat is stuck and water never reaches both sides of the motor exhaust manifolds?   If that were the case i questioned how the engine would not over heat, he said it gets enough cooling with the water routing to the one side to keep engine cool.   So if this was or is a possibility how would water get in the cylinders then if it is not coming via the thermostat?  Or is it possibly stuck partial open but not allowing adequate cooling to the manifold before it gets hot enough to crack with small burst?
@Alswagg
@212rowboat

To add a swift kick in the nuts, one of my jetskis decide to become a submarine overnight.  Friend stopped by and checked them last night and said they were fine.  I was heading there at 9am this morning to meet mechanic, i arrive and find 1 jetski and 1 submarine.   Buddy sent me some photos he took while down there, it was sinking.  He just didnt realize it because it had not sunk yet, the rub rail in the rear was at the water line.   Good thing he is a awesome attorney.  He would suck as a deck hand.  LOL

Wildboating

212rowboat

nah- after passing through the steering/oil cooler, water goes to pump and both sides of engine equally.  the 'stat just doesn't let it circulate until it reaches desired temperature, and then it will flutter open and close in attempt to maintain that temperature.  the thermostat neck and cover diverts water to the exhaust manifolds is all... 

there are one way valves in the neck that disallow back flow.. it may be worth looking at those for their health... 

this still sounds like a bad install on the manifold.... 

man... you ever thought about picking up mountain biking or hiking?  running or horseback riding?  maybe deer hunting or fishing (from the bank)?  you've got a black cloud my brother. 

Black_Diamond

If you think boats are money pits, I got news for you: horses are way worse.  Personal experience. lol

212rowboat

i won't argue that BD, but... it's pretty easy to tell if a horse is 'running' or not. 

Black_Diamond

Is the manifold cracking internally and externally?  Might just be me, but 4 cylinders water locked seems odd. Flapper installed correctly?

Black_Diamond

Has anyone bothered to verify water is flowing thru/out the manifold?  Cast iron will take a lot of heat. Cracking is from stresses in the metal: either from bolting on incorrectly/on a warped mating surface; or temperature shock. High rpm really ought not be the real issue unless major things are flexing under load. 

Wildboating

Boating and water is my life, such is the inevitable mechanical failures.   Jetski is all good, tore it down, cleaned out all the water, crc 656 all of it, especially in the turbo multiple times.   Its back up and running, cleaned up and ready to drop back in to fine the darn leak.   I did find both the o rings on the plugs were separated but i have a hard time believing 2 broken o rings caused this king of flooding.

Any how, back to the boat.   I have not verified but the mechanic says it is flowing.  He recently replaced the flappers too as they are going thru all the common sense stuff to them.  The riser stays cold...   Horses are not my thing unless it comes in pack of 600 or more.   

Manifold is cracking internally, letting water back in to cylinders 2-8 he says.  I still have not seen one of the manifolds.   Could this be a head gasket?  And they are just guessing it is cracked internally?  


Oh Drew, you mentioned the black cloud over my boat.  I kid you not, this photo was taken saturday as i realized the motor was hydrolocked again.   It is not just a cloud, it is a freaking mountain of a cloud.

J3ff

Broken it not looks like a great way to spend the little time we have on Earth 😊. I saw your post on the jet ski website...  Sorry to hear that.. I've got two Honda's as well. One is locked up from water in the oil. The second one runs on the cylinders. At the end of the day a photo like that makes it all worth it

Wildboating

@J3ff
Sorry to hear about your ski's.   What year are yours?  What is your user name at pwctoday?

Black_Diamond

Really hard to believe you had that many bad manifolds. Something not rightly sealing. 

Wildboating

The lead mechanic assures me it is being done right.  He has been doing this for 30 years.  Trying not to undermine the shop but it seems like this should be a easy fix. Im afraid they are going to tank my motor before figuring it out.  Owner said he is not putting new manifold in until he gets merc onsite or some new info.   I hope they don't stick me with 3 extra manifolds and all this labor.  They are missing something, this is why we pay tech rates.   I have had it bad enough as is.  I just want to enjoy this boat.  I have 2 new fridges and autopilot sitting in a basket ready for checkout if this boat will ever be fixed.  I have given it everything.  Ive spared no expense.  Unfortunately we don't have really solid and experienced techs around Cleveland and hauling the boat or motor out is a several thousand dollar venture to hope it is right when i put it back in.  I don't trust that process as the other part of the package could be part of this problem and i would only be a couple grand further in the hole

J3ff

Are you paying for all this? or is stuff being covered? I sure hope they are sharing some of the blame of their own specialists not being able to figure it out. 

Wildboating

That is correct, Al The mechanic said it was the same cylinders with water  2-8.  I suggested what i had heard to the shop owner.  He was following up with mechanic to see if there was in truth in it.

Wildboating

@J3ff
Truth is i don't really know.  When  the second one cracked owner said he was getting it warrantied and wasn't charging me for the part but i need to help with the labor.  Now we are on the 4th manifold.  I am just as concerned with all the other things they suggest as the problem replace and find out it made no improvements.    I have asked a few times where we are, i have not yet b been provided with an answer.  For the first time in 3 years the boat will not actually run anymore.   It always started and ran perfectly, just made low rpm on that motor.  They get the boat and determine manifold is cracked?  I have never had any hydro locking before, i did 3 weekend trips the last 3 weekends of the year and had no problems but they say there was water in the cylinders when they stared looking at it.   Now it won't stay running without busting a manifold and flooding the motor.  I am officially without a boat now and this weekend is my favorite of them all.  Always has been the big start to the season for my family and friends. 

Wildboating

I am strictly at the mercy of Mercrusier sending a tech to look at product they created 14 years ago.  I wonder if they will, let alone how long the at will take.  So sad.  Couldn't sell the boat even if i wanted too.  I would never pass this to someone else.   

I wish i had access to dealer cost on a set of new fully dressed motors. Im so deep in these I need a real break.  I would try to part these out or sell the good one and part out the one with all the brand new parts.  I have to figure out something, im so deep i really cant sell it even if i wanted too.  Most of the boat I have already redone.   One simple mechanical engine with a problem that cant be figured out, now 2 adding in the constant fried manifolds.

aero3113

Maybe Rinker can step up and put you in contact with their rep at Mercruiser? This has gone on for too long! Like you said, it's a simple mechanical engine.

J3ff

Wildboating said:

@J3ff
Truth is i don't really know.  When  the second one cracked owner said he was getting it warrantied and wasn't charging me for the part but i need to help with the labor.  Now we are on the 4th manifold.  I am just as concerned with all the other things they suggest as the problem replace and find out it made no improvements.    I have asked a few times where we are, i have not yet b been provided with an answer.  For the first time in 3 years the boat will not actually run anymore.   It always started and ran perfectly, just made low rpm on that motor.  They get the boat and determine manifold is cracked?  I have never had any hydro locking before, i did 3 weekend trips the last 3 weekends of the year and had no problems but they say there was water in the cylinders when they stared looking at it.   Now it won't stay running without busting a manifold and flooding the motor.  I am officially without a boat now and this weekend is my favorite of them all.  Always has been the big start to the season for my family and friends. 

I'd say if they even approach you with anything close to 10k you should tell them to replace the motor and give you 10k worth of credit towards it, mainly because they have NO CLUE as to what's going on and it's their job to HAVE A CLUE!

I can send you the invoice for going from a 350 raw water cooled to a 383 freshwater cooled and a brand new transom mount at the same time. It was an even 20k if I am remembering it correctly.