Mercruiser 4.3lx gen+ seized

[Karinshed]

Hi folks,
I'm a newbie, I live in Croatia on the Dalmatian coast, come from the UK.
I'm sorry to jump in with a problem, but I guess that's common enough!
I'll try to be a useful forum member going forward.

I have a Maxum 2300SC cuddy cabin 1996 with the above engine and an Alpha One Gen II sterndrive.

It's a 1996 boat. I bought it here last summer in the water and have since realised that the owner was not entirely truthful about his maintanance regime!

I ran it for about 2 hours in total last year, as there was an issue with the carb (flooding on hot start and on tickover when hot) . I took it out of the water and stored it on the trailer. (covered).

I was busy with building work on the house, so only now do I come to get it sorted for the water.

I found today that the engine is stuck. I took the plugs out, and tried to turn it over but it is stuck fast.

The front 2 plugs are corroded. The other 4 look ok.

I'm knowledgeable with motors, having worked on motorcycles all my life. But this is a little different.

I would like some basic advice on how to proceed. Is it more likely the engine or something to do with the stern drive?
When the boat was running, it seemed to all work fine, so I'm surprised it is seized. But I am new to boats.

It's an old boat, but I'd like to get her fixed up and slowly improve her over the coming years. I'm hoping I've not lost the lot here!

Thanks for any help,

Rod

 

[Bondo]

Ayuh,..... Welcome Aboard,..... Pull the drive, to see whether the problem is the motor, or the drive,.....

 

[Karinshed]

Hi, thanks.
I'll need to find out how to "pull the drive" first!
Given the scenario, is it more likely to be the driver or the motor?
Why would the front plugs be corroded around the electrode?
The bilge has been kept empty.
I'm trying to understand why it would be stuck.
Pulling the drive looks like a fairly major bit of work to discover if its the motor or drive. Is this really my next move?

 

[Karinshed]

[No message]

 

[Bondo]

Why would the front plugs be corroded around the electrode?

Ayuh,..... My Guess is water in those cylinders,.....

I'll need to find out how to "pull the drive" first!

Put the control in Forward,.....
Disconnect the aft end of the trim cylinders,....
Remove the 6 nuts,....
Pull the drive,.....

 

[Karinshed]

OK, that sounds relatively straight forward, thanks.
What am I looking for as a reason for water in the cylinders?

 

[Scott Danforth]

yes, pull the drive (if maintenance has been done regularly, its only 10 minutes). if your block is toast you have to pull the drive anyway.

regarding water in your cylinders your in salt water and the manifolds probably failed, or it got cold enough this past winter to freeze and crack the block.

you will need to pressure test the water jacket for leaks, then most likely pull the motor and do a complete tear down and if the block is cracked, replace the engine

here is some reading on the 4.3. any 1996 or later long block would work.

https://forums.iboats.com/forum/eng...history-of-the-4-3-liter-with-casting-numbers

 

[Scott Danforth]

haere is a link to some videos, including pulling the drive https://forums.iboats.com/forum/eng...gines-outdrives/604924-a-couple-of-new-videos

 

[Karinshed]

Thanks Scott. That's a little clearer, if not good news!
I'll pull the drive.
It never gets below zero here, so won't be frozen and cracked. Manifolds then.

 

[Scott Danforth]

dont say never.....many people down south here thought the same.... this past winter was brutal and a simple search showed temps in Croatia this past January were below 0

 

[Karinshed]

Fair enough! But not where I am, nothing lower than 3 degrees this winter. 20 miles away, yes, -10 degrees.

I'm looking for a fuse, something popped when I bridged the starter solonoid and it wasn't the breaker. Is that likely to be under the dashboard or in the engine bay?

 

[Bt Doctur]

anything lower that 32 Deg F will cause a crack

 

[Karinshed]

anything lower that 32 Deg F will cause a crack

I'm working in Celcius! 3 degrees is 37.4 F. It didn't go below that where the boat was stored.

 

[Scott Danforth]

Still suggest that you pressure test.

 

[Karinshed]

I will, just to be sure. Thank you for your help.

 

[Lou C]

A common source of water in the cyls is a failed manifold to exhaust elbow gasket, with the older style wet joint exhaust it is a common problem, and these should be taken apart after 5 years use in salt water, or anytime you see rust stains running from the joint between the manifold and the exhaust elbow. The plug you showed suggests a LOT of water in the cyls. You can also get this from a failed intake manifold gasket in the front where the water passages under the thermostat housing join up with the cyl heads. Not as common though. Drain the manifolds and take off the elbows, then look down the center exhaust port. If you see rust trails in the center exhaust port that's one way water got in.

 

[Karinshed]

Update.
I have pulled the drive, all looks good.
I have put diesel in the bores.
I have removed the manifolds and elbows, they are very rusty and will need replacing.
I'm waiting to see if the engine frees off.
Meanwhile i'm considering wether to rebuild the existing 1996 engine of unknown hours and iffy mantenance regime.
Or to replace the whole motor.
I need to pressure test the block to see if it is cracked before I decide as well.
Either way, I need new manifolds and elbows. Is it best to replace with stock or is there a better after market replacement?
There was no water in the manifolds at all. I have seen no water in the bores, although it's not easy to be sure at this time.

 

[Scott Danforth]

stock is high quality. if you go aftermarket, stick with OSCO or BARR as they have equally high quality.

as for the whole motor, not sure how easily available complete motors are in croatia as they are here.