Motor seized?

[Namluu248]

I have a 1996 century with a 4.3 vortec engine. I just put a new long block in it did the 10hr break in on the motor, ran fine yesterday. went to start it today and won't turn over so checked my battery it was good so thought it might be froze up starter so I took off the starter and try to crank the motor by hand motor turn but really hard when turning by hand. Could this be a seized motor? Thanks in advance

 

[Grub54891]

Re: Motor seized?

Could be lots of things. From a dead battery to a bad starter/connections. Did ya check the oil? Is there water in the cylinders?
Gotta start with the basics and work your way in. Was the temp and oil pressure normal the last time it ran?

 

[Turn-n-Burn]

Re: Motor seized?

I'd start with pulling all the plugs first and then hand crank.

 

[RogersJetboat454]

Re: Motor seized?

What killed the last engine?
Were the exhaust manifolds re-used from the previous engine?

 

[Namluu248]

Re: Motor seized?

Could be lots of things. From a dead battery to a bad starter/connections. Did ya check the oil? Is there water in the cylinders?
Gotta start with the basics and work your way in. Was the temp and oil pressure normal the last time it ran?

I got 2 new battery and just went to autozone and got them check they were good and with oil pressure was at 45 with temp I didn't check it should of check it. I just did a oil change and yes oil looks good noting unusual ,so I just took off the outdrive thinking if it's going bad and freezing up ,I could turn the outdrive by hand so the out drive is good right? So went to take off 3 spark plug and turn the motor by hand she turn ok tell I hit one point were its kind of hard to turn but I notice water coming out of the spark plug hole. Hope it's not a seized motor just got the boat and a new motor and it's giving me a headache already

 

[Namluu248]

Re: Motor seized?

What killed the last engine?
Were the exhaust manifolds re-used from the previous engine?

Yes I reused the old from previous

 

[Namluu248]

Re: Motor seized?

What killed the last engine?
Were the exhaust manifolds re-used from the previous engine?

Last owner didntwinterize and crack the block and water got in to the oil

 

[chimmike]

Re: Motor seized?

sounds like exhaust manifolds are letting water get in the cylinders. pull plugs out of ALL the cylinders and try cranking by hand, AFTER you spray sea foam/deep creep into every cylinder and let it sit.

 

[Turn-n-Burn]

Re: Motor seized?

yep, pull all the plugs and give a few squirts of oil in each, then rotate the engine by hand. Then pull the manifolds and check for cracks.

 

[RogersJetboat454]

Re: Motor seized?

Last owner didntwinterize and crack the block and water got in to the oil

Bingo..
Chances are the manifolds/risers cracked when the block cracked.
Always good practice to replace them with a new engine install, especially if they're older, or were bolted to an engine that froze to death.

Hopefully they didn't wreck your new engine...

 

[Namluu248]

Re: Motor seized?

Bingo..
Chances are the manifolds/risers cracked when the block cracked.
Always good practice to replace them with a new engine install, especially if they're older, or were bolted to an engine that froze to death.

Hopefully they didn't wreck your new engine...

So I took off the manifold and the riser everything seem to look ok no crack or anything.but notice my exhaust shutter worn real bad. Could this cause water to get in the cylinders?

 

[RogersJetboat454]

Re: Motor seized?

So I took off the manifold and the riser everything seem to look ok no crack or anything.but notice my exhaust shutter worn real bad. Could this cause water to get in the cylinders?

Yes they have the potential to cause problems if they can't do their job.

Did you separate the risers from the manifolds? If so, how did the sealing surface between the manifolds and risers look? If they are pitted, rotted away, or uneven, they will leak.
Also sometimes you can't see the cracks, or they only become an issue when the manifold is hot or under pressure. You can try filling them with water to see if they leak, but as I said before, it's good practice to replace them with a fresh set, especially in a situation like they were in. Personally I wouldn't be even bothering with them if the health of a new engine is on the line.

 

[Turn-n-Burn]

Re: Motor seized?

can also do a acetone test on the manifolds

http://forums.iboats.com/mercruiser...s/testing-exhaust-manifolds-leaks-288629.html