05 Maxum 4.3L Mercuiser hydrolocked

[Slater]

Have my uncles 2005 maxum sr1800 with a 4.3l mercruiser with 22 hours, in San Diego.
Its my uncles ride which he bought used & doesnt use it much. Im not sure about history of the boat but he has used in in salt quite a few times. Im a ford heavy line engine tech & slammed a starter in it for him & he said take the boat out since she just sits. Took it out for a few hours & saw that the tstat gasket started streaming a leak back torward the base of the carb so called it a day & headed torward the docks. Shut her down while going for the trailer..
Tried to restart & knew she was hydrolocked.
Got home & rolled out a 6 sparkplugs & appears that I may have had water in all 3 cylinders on right side head.
Removed right side riser & gaskets, has a spacer between riser & exhaust manifold. Metal type gasket with orange oring at front & back round waterports & typical exhaust gasket material at square exhaust port. Im not seeing the 1/4inch water chanells as in the pic that Don S posted. Newer designed manifolds?????
Can see some surface rust on the inside of the exhaust manifold But not seeing much of anything on the riser or gaskets. Not sure what my failure is or exactly what im looking for. Just want some insight before I teardown even further prematurely. What is more prone to failing in this application with only 22hours?
DID FIND COMPLETE BLOCKAGE A THE FRONT ROUND WATER INLET PORT AT THE EXHAUST MANIFOLD & PUNCHED IT OUT, JUST SOME NASTY BUILD-UP WHICH I REMOVED EASILY USING A SCREWDRIVER. This was at the area where theres a access large allen plug.
Might try & do the acetone test while the manifold is still on the engine.
Any insight would be appreciated.

 

[cr2k]

Re: 05 Maxum 4.3L Mercuiser hydrolocked

I have seen some head gaskets go and fill a few cyls. A compression check will tell a lot.

 

[Joshua Nichols]

Re: 05 Maxum 4.3L Mercuiser hydrolocked

All three cylinders eh? Do the acetone test.. Sitting salt water will eat up some cast iron.. Good luck.. BTW that blockage will make that manifold run hot.. Did the engine get hot while u was out?

 

[TilliamWe]

Re: 05 Maxum 4.3L Mercuiser hydrolocked

You probably have a bad exhaust manifold. It seems to be leaking internally, that's why you see the rust in it.

 

[Slater]

Re: 05 Maxum 4.3L Mercuiser hydrolocked

I brought the boat to work with me & when i had a minute if filled the water jacket with with acetone & isolated the crack to the center pinacle in the manifold! Any insight on wheres the cheapest place around to pickup a "dryjoint type exhaust manifold, Thanks for any leads! 864612T01


PORT OR STARBOARD - FITS MCM GM V-6 (262 CID) ENGINES WITH DRY JOINT EXHAUST (S/N 0M615000 AND UP) (2002 AND NEWER). 864612T01 Thanks for any leads!

 

[Fishermark]

Re: 05 Maxum 4.3L Mercuiser hydrolocked

Any insight on wheres the cheaperst place around to pickup a "dryjoint type exhaust manifold 846612t01

Some of the usual places I have shopped for discount parts don't seem to carry your manifold. I think you may have switched a couple numbers however - isn't the part # you need 864612T01 ? Looking around it seems they run in the neighborhood of $340. Here's one place.

 

[Joshua Nichols]

Re: 05 Maxum 4.3L Mercuiser hydrolocked

Might as well change em as a set.. The other one will fail soon too.. I find lots of cheap parts on ebay.. No manifolds are cheap..Good luck

 

[Slater]

Re: 05 Maxum 4.3L Mercuiser hydrolocked

Got my parts. Need some torque spec help. its an 05 4.3 mercruiser with a dryjoint type manifold with a 3inch spacer between the riser elbow & manifold. I saw a 20 ft.lb/ spec for the manifold bolts.
Cant seem to find any riser bolt specs, any help would be appreciated.