2005 4.3 mercruiser bad engine

[Papakevin63]

Need a new motor

Hello,after running the boat for 1 yr, after changing exhaust manifolds an risers, went to start it and, it ran for 10 min, hear a knocking notice, shut it down. Pulled all plug and plug 1 was. Smashed up being hit by piston.. Do I I now just replace the block?thinkingnto buy base with heads on it and adding my partsto , like starter, alternator and so on.
Is this my best option, does anyone one know if putting in a reman vs new is any difference? Will new last longer in the long run? Where can I get a reman or new engine at a hellmof a price? Is mine the m90? Please help somone

 

[R055]

You should start a new thread as this isn't about the original problem anymore. You'll get a bunch more replies that way.

 

[Papakevin63]

Don't know how to Starr new thread

 

[Bondo]

Don't know how to Starr new thread

Ayuh,.... There ya go, a new thread,....

To start yer own, click the orange button( + new topic) at the upper portside of the forum ya wanta post in,.....

 

[Fishermark]

Not having seen the original thread... what are you working on?

 

[R055]

Not having seen the original thread... what are you working on?

Carbed 2005 mercruiser 4.3,

 

[Scott Danforth]

you should only need a new long block and switch over your other stuff. however you will want to find what caused the rod to let go and hit the spark plug.

Im a build it yourself guy, so I would do the reman myself. nothing wrong with a remanufactured motor.

 

[Bondo]

Not having seen the original thread... what are you working on?

Ayuh,.... My bad,... The original thread,....

 

[Papakevin63]

#1
Need a new motor
September 15th, 2016, 09:22 PM
Hello,after running the boat for 1 yr, after changing exhaust manifolds an risers, went to start it and, it ran for 10 min, hear a knocking notice, shut it down. Pulled all plug and plug 1 was. Smashed up being hit by piston.. Do I I now just replace the block?thinkingnto buy base with heads on it and adding my parts to it like starter, alternator and so on.
Is this my best option, does anyone one know if putting in a reman vs new is any difference? Will new last longer in the long run? Where can I get a reman or new engine at a hellmof a price? Is mine the m90? Please help somone
Last edited by Papakevin63; September 15th, 2016, 09:28 PM.

Anyone local in jacksonville, Florida that can do this? What is a good price to do this? Ie. Dropping in a block vs complete engine drop in?

What would be a good labor price per hour? How many hours does this typically take?.

Ty all for your help

 

[Papakevin63]

Posted new thread under engine with all Ty bonds

#1
Need a new motor
September 15th, 2016, 09:22 PM
Hello,after running the boat for 1 yr, after changing exhaust manifolds an risers, went to start it and, it ran for 10 min, hear a knocking notice, shut it down. Pulled all plug and plug 1 was. Smashed up being hit by piston.. Do I I now just replace the block?thinkingnto buy base with heads on it and adding my partsto , like starter, alternator and so on.
Is this my best option, does anyone one know if putting in a reman vs new is any difference? Will new last longer in the long run? Where can I get a reman or new engine at a hellmof a price? Is mine the m90? Please help somone
Last edited by Papakevin63; September 15th, 2016, 09:28 PM.

 

[Papakevin63]

New post is here

http://forums.iboats.com/forum/engi...rives/10277479-2005-4-3-mercruiser-bad-engine

 

[Papakevin63]

To Scott: you said just to replace with new long block, but to find out what caused it.. With new block problem would be elimated correct? And whe disassembling blown engine should discover cause, correct?

 

[Papakevin63]

Is a Renan just as good as a new on? I keep being told that the reman don't last as long...?

 

[NHGuy]

A proper reman IS effectively new. Everything that matters gets changed. And yes, open the old motor to find out what broke it so you don't cause the same thing with the new one.

 

[Papakevin63]

Got heads off and found a bent rod, one valve spring was broken as well

 

[Papakevin63]

To nhguy found bent rod and broken valve spring, don't know what's caused the failure. At this I'm thinking it don't really matter if new long block goes in correct? Did discover water in cylinders, which I'm assuming there must be a crack in block, any other ideas or suggestion is appreciated

 

[NHGuy]

Others will chime in yet. So bent push rod, right? And broken valve spring. See if there's a bad connecting rod in that hole too.
Did I understand you to say this all happened ten minutes of run time after the exhaust change? If so was the exhaust new?
It's probable that water got in the combustion chamber. Probably through an exhaust valve at idle. Sometimes it gets in while the engine is sitting, then on restart it breaks things. It could have come from a leak into the exhaust from the water jacket if the parts were used. Or it could have come from the joint between the exhaust manifold and the exhaust riser. That's more likely.
Wherever it came from or whatever caused the fail needs to be determined so you can prevent it reoccurring.
See if that piston is clean from the water wash. Or any others.
Wow, that stinks. Engine could be kaput.
Did you remove the head in the boat? Take off the drive and try to turn over the engine with the starter. Or if it's on a stand try to turn it with a breaker bar. Might as well remove the oil pan to see connecting rods etc from underneath too.

This will answer whether to get an engine or heads.

 

[Scott Danforth]

bend connecting rod or bent push rod?

if its a pushrod, you could be down to a bad head from rust from water comming from your exhaust manifolds. bent connecting rod is hydrolock.

the water in the cylinder is not a good thing. I would seriously pressure test your exhaust manifolds and risers. most likely you have a bad riser gasket, especially if only after a year on the manifolds.

if you have GLM manifolds, you need to take a large flat file and true up the mating surfaces prior to bolting them together or they leak. if you used the Siera green gaskets, they leak (they are called green leakers on here).

 

[Papakevin63]

Exhaust manifolds and riser were put on abut 1yr ago, it's 2005 boat and replaced them in 2015, Right before I replaced them the engine was hesitating, miss firing and ran hot, changed exhaust and riser, ran good for a year, 2016, now bent rod.. I'm thinking, the main cause or the damage occurred when the exhaust and riser were no good causing heat to engine and now it finally gave. That's what I think, but I don't have enough knowledge to be sure or to make that call, anyway picking up new long block on Wednesday, guess it could of been new risers or gasket,but no sign of wetness when in bolted... Valve cover off and all accessories as well, getting ready to pull engine and replace with reman long block, any suggestion to prevent this from happening again?

Ty for your feedback

 

[NHGuy]

As Scott said, verify with a straight edge or flat file the mating surfaces between the exh manifolds and risers. No green paper gaskets, use new graphite coated steel mesh gaskets. Use new gaskets any time you unbolt them, your engine is not worth the risk of water getting by.