MerCruiser 5.7 inboard gas engines not used in years – what to do

RBBeasley

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Sep 3, 2024
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Preparing to sell a 32' Carver convertible with twin MerCruiser 5.7 gas engines that have not been started in over 10 years. What should be done to resurrect these?
 

Scott06

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Apr 20, 2014
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Preparing to sell a 32' Carver convertible with twin MerCruiser 5.7 gas engines that have not been started in over 10 years. What should be done to resurrect these?
First check to see if there is oil in them. I would take the plugs out, squirt some oil in cylinders. If so put a battery in and bump the starter see if they turn freely.

If not locked up - See if you can suck the oil out. add fresh oil and change filter. Would run them with plugs out and coil wire grounded until you see oil up at rockers . If points you will need to service points/condenser dwell to get them running

Drain any fuel in the tank or run off a remote tank to start.

You will also need to check oil in transmissions assuming this is inboard. If it is an I/o boat change drive lube
 

RBBeasley

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First check to see if there is oil in them. I would take the plugs out, squirt some oil in cylinders. If so put a battery in and bump the starter see if they turn freely.

If not locked up - See if you can suck the oil out. add fresh oil and change filter. Would run them with plugs out and coil wire grounded until you see oil up at rockers . If points you will need to service points/condenser dwell to get them running

Drain any fuel in the tank or run off a remote tank to start.

You will also need to check oil in transmissions assuming this is inboard. If it is an I/o boat change drive lube
Following up. Yes both engines have Walter V/drive transmissions.
One of the prospective buyers suggested that I confirm engines will at least crank over and are not frozen up. He suggested hand cranking and then maybe using "mystery oil" to soak after taking spark plugs out.

Would that type of oil work? How much should we use? at least videotaping that they actually turn over and run even using a carb starter spray should help with the sale giving a buyer some potential piece of mind.

Separate issue there is a lot of rust on the engines, pulleys, transmissions, everything pretty much. Would you recommend using CLR or naval jelly? Or Any particular solution I can spray over everything to at least rinse away the rust?

The port engine when we were fishing, had a high-pitched spinning type sound which resulted in having no turning of the prop. Motor was fine, but didn't allow us to go anywhere which is why we took it out of the water 10 years ago. I've been told that issue is either a coupler that has broken in between the engine and transmission or that potentially something inside the Walter V – Drive transmission broke and needs to be rebuilt. Any thoughts on that? Thx again
 

RBBeasley

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Fyi
 

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flashback

Captain
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Hopefully you winterized it 10 years ago, if not, it's scrap iron. Tell your buyer to come and get it if it's what he wants.
 

tank1949

Lieutenant Commander
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Apr 4, 2013
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1,896
If saltwater used, get ready to spend a bundle of money getting it sea worthy. Replacing motors and cooling....
 

1985 Century Mustang

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Hopefully you winterized it 10 years ago, if not, it's scrap iron. Tell your buyer to come and get it if it's what he wants.
Not true, I got a boat that was sitting in the driveway for 12 years unused, it's a Merc A1G1 140hp. I had to rebuild the carb and change all the seals in the outdrive and a few other minor things. The boat is fine today, and I use it regularly.
 

Scott06

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Not true, I got a boat that was sitting in the driveway for 12 years unused, it's a Merc A1G1 140hp. I had to rebuild the carb and change all the seals in the outdrive and a few other minor things. The boat is fine today, and I use it regularly.
Winterized is the point he was making. If it wasn’t properly winterized engines are scrap if in colder climate

Is that the boat u did the transom or engine mount stringer on ? Or am I mixing up posts
 

1985 Century Mustang

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Mar 9, 2023
Messages
532
Winterized is the point he was making. If it wasn’t properly winterized engines are scrap if in colder climate

Is that the boat u did the transom or engine mount stringer on ? Or am I mixing up posts

Yes, I'm not sure if my boat was winterized or not, but I get your point.
 

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