1984 mercruiser

[Secondboat1979]

Hello, I am not completely new here but seems that way with all the updates. I just started new account. This is my second boat I just got it for the right price of free, it's a 1984 Chris craft scorpion 230 limited with what I can tell is a mercruiser 260 drivetrain, engine was completely full of rainwater for probably about 6 years I vacuumed out all the water and some sluge, and stated filling engone with at and diesel fuel mix hoping it will free up engine for a rebuild, termites ate the seats and floors so I have my work cut out for me. So it has some sort of holly carb, eldebrock valve covers, upgraded coil system, thunder thumper exhaust, and it is currently seized, I will update as soon as I can with more info but just got the boat and took years of trash out of it. I may be in over my head but any pointers are welcome

 

[alldodge]

Instead of rebuilding the motor, find another in the junk yard to rebuild.

 

[Scott Danforth]

engine was completely full of rainwater for probably about 6 years

not even a sledge hammer would free the pistons from the cylinders. consider the block and heads a boat anchor at best. you need a new to you motor

 

[Secondboat1979]

I'll give it two weeks of soak things, and go from there look like a boat anchor at this point but will see, I'm pretty handy and can rebuild if I can get it moving

 

[Scott Danforth]

even if it moves, the block bores are going to be pitted beyond the rings sealing.

 

[Panoguy]

even if it moves, the block bores are going to be pitted beyond the rings sealing.

I was thinking like you are SecondBoat, till I read Scott Danforth's post; didn't think about that. Sorry to say, I also think that it's time to start looking for a new-to-you, or long block... you'll never get good compression, & probably end-up messing-up the rings, so the boat will end-up being a no-power smoker.

 

[briangcc]

IF it was a classic block I'd say take it to a machine shop and they might be able to sleeve it. You may very well deal with overheating afterwards - ask how I know. Since it's a dime a dozen Chevy, go get a long block or a core from a junkyard.

 

[Scott Danforth]

you can build a brand new (and I mean brand new) motor with all new parts as either a 5.7 or 6.2 for about $3500 or less. that is carb to flywheel. reman is about $2200 and most running salvage yard motors would be about $400 from a truck

 

[Secondboat1979]

It has the 5.7l in it such a shame the guy was repowerin it pretty good had a $600 holly carb on it plus alot more. I'll start poking around I'm in FL should have alot sitting around.

 

[Scott Danforth]

Hit LKQ anywhere in FL, unbolt the motor yourself for $202 https://www.lkqpickyourpart.com/locations/LKQ_Pick_Your_Part_-_Tampa-180/prices/

the moment the holley was taken out of the box and bolted to the motor, the price became half....

if your block and heads are 1984 vintage (perimeter bolt heads, 2-piece RMS crank, you can get more power by getting a 1996 or newer truck motor (roller motor with vortec heads). would require new intake.

if you go a pull-out motor, remember you only will be using the long-block. all the rest of the truck stuff will not be used.

 

[Secondboat1979]

That's is great info, thank you so much it might make thus project possible I was looking at crate motors for like $1,500

 

[Broaters]

Hello,

we went through the same issues last year on our boat. We are located in Belgium and the engine block are not as easily found here as in the US so we decided to rebuil ours.

We removed the heads to discover a lot of water and rust in the bores. We soaked it in WD40, gasoil and other penetrating stuff (not very eco friendly...) and managed to remove the pistons one by one. It appears that only 2 of the 8 cylinder were blocked enough to avoid rotation of the engine.
after cleaning with a wire brush we used a BRM Flexhone and were able to clean most of the corosion off. only a very small low spot remains. good enough for us.

from what I read on the boats and cars forums it is quite cheap in the US to have a shop re-bore your cylinder and buy a new piston set.
In total we were able to rebuild the engine for less than 1000 USD. On our point of view it makes sense considering block and heads availability here plus it was a lot of fun and learning.

the engine is now running perfectly