Saltwater in engine due to rusted out exhaust mainfold, how bad?

[24-seven]

Hi,

Just purchased a Larson 250 Hampton 1997,with a 5,7 merc/Alpha one (300hours), to have as a winter project. The boat was really cheap with a siezed engine (PO says it does not turn w/o plugs when trying on the crank with a ratchet) due to saltwater intrusion from a rusted out exhaust mainfold and has been sitting for about a month with water in at least 1 cylinder.

I?m use to restoring engines and not put of by this, the question is what level of repair to expect:

1. Change mainfolds/risers pour rust solvent in rusted cylinders, change oil and try to rotate engine
2. Pull the head right away to inspect the damage, pour rust solvent and tap lightly on siezed piston/pistons
3. Lift the engine out to do a complete restoration with a rebore.

In your experience what is called for here of the above?

Going to collect the boat on saturday...

 

[tpenfield]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

One month with salt water might be too long. Probably should try to rotate the engine by pressurizing some of the cylinders, but be prepared to go to option #2 that you have outlined.

 

[jerryjerry05]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

Pull the head and see how much gunk has built up.
The head will probably need to be rebuilt.
A month with salt water can ruin the whole thing.

 

[24-seven]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

Thanks!

Guess starboard head is coming off then. Would be great if I could avoid pulling the engine, had the engine (also 5,7 merc) out twice last winter when restoring my Chris Craft Bowrider....

 

[HT32BSX115]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

Thanks!

Guess starboard head is coming off then. Would be great if I could avoid pulling the engine, had the engine (also 5,7 merc) out twice last winter when restoring my Chris Craft Bowrider....

Howdy,

I would pull the engine. 1 month of salt water in a cyl makes it junk.

Even if you "free" it up, that cyl will possibly have broken/or otherwise damaged rings that will never re-seat.

Pull both heads too........makes the block lighter to lift out.


Regards,


Rick

 

[Walt T]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

Don't bother pulling heads. That engine is junk. The head on that side is probably junk also. I've seen it a hundred times. Even a week with salt water can do it.

 

[Bondo]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

Hi,

Just purchased a Larson 250 Hampton 1997,with a 5,7 merc/Alpha one (300hours), to have as a winter project. The boat was really cheap with a siezed engine (PO says it does not turn w/o plugs when trying on the crank with a ratchet) due to saltwater intrusion from a rusted out exhaust mainfold and has been sitting for about a month with water in at least 1 cylinder.

I?m use to restoring engines and not put of by this, the question is what level of repair to expect:

1. Change mainfolds/risers pour rust solvent in rusted cylinders, change oil and try to rotate engine
2. Pull the head right away to inspect the damage, pour rust solvent and tap lightly on siezed piston/pistons
3. Lift the engine out to do a complete restoration with a rebore.

In your experience what is called for here of the above?

Going to collect the boat on saturday...

Ayuh,.... That motor is probably now a Moorin' Block,....

Long Block it, 'n salvage what ya can from the Anchor,...

 

[24-seven]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

I hear you guys, Saltwater is eeeevil!

Am I completly wrong when asuming I will be able to restore the engine, no matter what?

Worst case I'm thinking: rebore with new pistons, new bearings/gaskets etc. And pherhaps a new head.

Marine Longblocks are pretty expensive here in Sweden. After adding freight, VAT and custom fees to the typical $2300 (1996-) remanufactured Marine Longblock found in the US, the total is more like $4500-$5000....

 

[HT32BSX115]

Re: Saltwater in engine due to rusted out exhaust mainfold, how bad?

The block is made out of the same cast iron as the manifolds.

You won't know until you get it apart