Bad 1970 Mercruiser Engine, Please tell me there is still hope.

[CW2cJ]

When my parents died last year, my wife and I decided we would bring their boat from Colorado to Florida. I finally decided to see how the engine was and found that it would not turn at all. I removed the cylinder head to find the number three cylinder is cracked.
The boat is a 1970 Newman DeVille with a 165HP Mercruiser engine (Chevy 250 I6). I know I just went from a cheap boat to a money pit but since this has sentimental value I would like advice on if there is anything I can do to make this boat run again? I really am not rich enough to own a boat but I do live in South East Florida and love to dive so having a boat would be great. I am wondering if I can put in a newer l6? Could I convert this boat to an Outboard which would give me more room in the boat for the dive gear? I am a do-it-yourself type of person. So can I save this boat or do I have to bury it?

 

[racerone]

What condition is the transom in ?-----How about stringers under the floor ?------Engine repairs are easy in comparison.-----An inline 6 should not be hard to find.

 

[CW2cJ]

So I just read on another forum in here that converting to an outboard is not a good idea. I found a running GM 250 I6 engine on eBay that I can maybe take the block from and put on the head and exhaust manifold from the original on?

 

[CW2cJ]

What condition is the transom in ?-----How about stringers under the floor ?------Engine repairs are easy in comparison.-----An inline 6 should not be hard to find.

Transom seems to be fine. Stringers? I am new to this boat thing so I have to say I do not know what those are. Can I use about any inline 6 or do I need to be more exact?

 

[CW2cJ]

Well, I looked through other forums here and found the stringers are the cross pieces that go in the hull under the deck, correct? It also seems that it is difficult to determine their integrity on my own. One thing that may be bad is the the engine mount came right out of the deck without having to unbolt it. If I tear out the deck, can the stringers be replaced? No better time to do that then when the engine is out, right?

Edit- I changed "floor" to deck. Dang, I am an old Marine, I know the terms for boat/ship parts. At least, I used to. I hate getting older. lol

 

[Bondo]

Transom seems to be fine. Stringers? I am new to this boat thing so I have to say I do not know what those are. Can I use about any inline 6 or do I need to be more exact?

Ayuh,...... Welcome Aboard,...... Stringers are the structural pieces that run lengthwise under the deck, 'n bulkheads run crosswise,...
They're usually a plywood core covered in fiberglass, like the transom, the plywood rots away, leaving a weak structure,.....
Lotsa great info on such over in our Restoration forum,....

Ya need a Chevy I6, that has the extra hunk of cast iron on the forward starboard corner of the block, to mount the marine motor mount too,.....

Rather than resurrecting that original antique driveline, Finding a rotten hull with a much newer driveline will probably be the cheapest route to a nice running ole hull,.....
You could go I4, I6, V6, or V8, depending on the size of the hull,....
Just stick with Chevy power,......

 

[CW2cJ]

Ayuh,...... Welcome Aboard,...... Stringers are the structural pieces that run lengthwise under the deck, 'n bulkheads run crosswise,...
They're usually a plywood core covered in fiberglass, like the transom, the plywood rots away, leaving a weak structure,.....
Lotsa great info on such over in our Restoration forum,....

Ya need a Chevy I6, that has the extra hunk of cast iron on the forward starboard corner of the block, to mount the marine motor mount too,.....

Rather than resurrecting that original antique driveline, Finding a rotten hull with a much newer driveline will probably be the cheapest route to a nice running ole hull,.....
You could go I4, I6, V6, or V8, depending on the size of the hull,....
Just stick with Chevy power,......

So you are saying that I can restore this old boat and save the memory of my mom and dad, THANK YOU! Everyone needs a hobby. I thought diving was expensive enough. Let's add rebuilding a little boat (it is only 17') to that so I can stay bankrupt forever. LOL

 

[Rick Stephens]

I bought a relatively old boat that had pretty good wood underneath the fiberglass and was powered with an I4. I got the bug and went looking for a rotted out hulk with a V6 and newer outdrive. Ended up way out ahead and had a blast learning and doing the work. I own a sh!tload of tools since I make my living with a welding shop. I still spent a bit on different tooling required to do fiberglass work.

End result though - I replaced a bit of the transom and just a small bit of the floor, encapsulating both in fiberglass so no water can get in in the future. The 4.3L V6 is amazing power and easy on the pocket. Below's what the power package and already stripped hull looked like that I picked up for $1500. The motor needed a rebuild after they left it without a cover over the carburetor and water dripped into it rusting the freshly bored cylinders and brand new pistons and rings. Was still a great buy and sold the old motor and drive parts to pay most of the costs.

Ya learn a lot doing this. And loads of help here.

Rick

 

[achris]

A project I've always thought would be interesting, and you have the opportunity to do it here.

My boat is an older (1972) hull, and originally had an inline 6 (165). When the drive broke a tooth and chewed up the top box I was only in the position to replace the drive (and be left with the old transom assembly full of corrosion) or replace the entire drive line. I opted for the entire new drive line, and don't regret it for a moment. But, given the same option today, I might go an 'unconventional' route.

I'd rebuild the 165 (freshen it right up), and change out the rest of the system for a near new (and vastly superior, IMHO) Gen II drive and transom assembly..

There would be quite a bit of work involved, you'd need to find the flywheel housing from a newer 3 litre, and the existing coupler would need to be removed and the flywheel (very accurately!) drilled for a new style coupler. You may also need to do a bit of work to get the exhaust pipe to line up, and I'm sure there would be a few other challenges along the way, but the end result would be the 'original' engine with a very must updated drive and transom system... And if I was replacing the engine block and head with a 'non-marine' one, I'd be putting a closed cooling system on it. (which I did have on my original 165, and the manifold water reversing system).

I may even go looking for a boat to do that to. ;-)

BTW, that cracked cylinder may be able to be sleeved. Talk to your local machine shop.

Chris.........

 

[tank1949]

Transom seems to be fine. Stringers? I am new to this boat thing so I have to say I do not know what those are. Can I use about any inline 6 or do I need to be more exact?

No disrespect but "seems" may cost you a fortune and hard work, if there is rot. Trust me. I have been working on a restoration for over 4 years due to an incompetent marine surveyor. Take 1/4" drill bit and drill at least a half dozen holes around inside transom assembly and a couple near drain plug. Don't penetrant the outer gelcoat. If mush, crumbling wood, black crud or drilling into hollow, expect lots of work. If not fill with 5200. Repeat similar to stringers. If ok, you dodged a bullet. If bilge room, I believe a small block Chevy motor will be much easier to find than a 250. Maybe not...

 

[kenny nunez]

There has to be a few marine salvage yards where you are located. I am sure one of them will be able to supply you with a good used set up. Go ahead and have the engine checked out, since it was used in fresh water there is a good chance it can be rebuilt.
As far as hull repair and you are not equipped to do that then just ask around and you will find someone who works for cash.

 

[CW2cJ]

I just wanted to post an update here. After attending the Ft Lauderdale Boat Show, we were told to convert to an outboard and rebuild the whole boat. I started reading and decided this may be out of my league, right now, as I did not grow up around boats and would be trying to do something major with no knowledgebase to draw from. I really appreciate the replies here and I look forward to learning more. We decided that we should just take the engine out and check around locally to see what we can do (resleeve, rebuild, or different block). We have to update a few things to get this boat ready for the ocean but, as I am already 52, I would rather get this thing on the water and enjoy it for a bit and learn before taking on a major rebuild project. If the boat lasts us a few years and we decide we really want a boat then we can start the rebuild then and will, hopefully, meet some locals that could help guide me. We may decide that we don't want to "own" a boat and just join a boat club instead. We may decide we want to spend money on a new boat. I will start small and work my way up.

 

[Scott Danforth]

Ft Licquordale (Lauderdale) is geared toward big white boats (yachts)

conversions that work are few and far between

if you want it up and running quickly with minimal work, look for a complete pulley to prop longtail

follow Chris's comment, however i would start with a running motor

I'd rebuild the 165 (freshen it right up), and change out the rest of the system for a near new (and vastly superior, IMHO) Gen II drive and transom assembly..

I would find a running 250 cubic inch out of a truck for $250 and spend a few hundred on gaskets, etc.

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[nola mike]

One thing that may be bad is the the engine mount came right out of the deck without having to unbolt it.l

At best it sounds like your mounting pad is bad. You really need to check the transom and stringers before proceeding. The boat really won't be safe or useable if there's rot. And based on the engine and your situation wouldn't be salvageable (yes, everything's salvageable with enough time and money).

 

[Bondo]

I just wanted to post an update here. After attending the Ft Lauderdale Boat Show, we were told to convert to an outboard and rebuild the whole boat. I started reading and decided this may be out of my league, right now, as I did not grow up around boats and would be trying to do something major with no knowledgebase to draw from. I really appreciate the replies here and I look forward to learning more. We decided that we should just take the engine out and check around locally to see what we can do (resleeve, rebuild, or different block). We have to update a few things to get this boat ready for the ocean but, as I am already 52, I would rather get this thing on the water and enjoy it for a bit and learn before taking on a major rebuild project. If the boat lasts us a few years and we decide we really want a boat then we can start the rebuild then and will, hopefully, meet some locals that could help guide me. We may decide that we don't want to "own" a boat and just join a boat club instead. We may decide we want to spend money on a new boat. I will start small and work my way up.

Ayuh,..... The largest, most complete data base, worldwide knowledge archive, Is the Repair, 'n Restoration forum, right here at iboats,.....

Again, as noted above, investigate the condition of the hull 1st, before you even consider goin' out on the ocean,.....
or spendin' a dime on any driveline,....

 

[CW2cJ]

Ayuh,..... The largest, most complete data base, worldwide knowledge archive, Is the Repair, 'n Restoration forum, right here at iboats,.....

Again, as noted above, investigate the condition of the hull 1st, before you even consider goin' out on the ocean,.....
or spendin' a dime on any driveline,....

That would mean that I tear the old wood deck out and use a small hole saw to drill test holes in the stringers? Then, if no rot is found, fill the holes (as mentioned above) and replace the deck then go about engine repair? For the most serious question:
I do feel that I am skilled and do a lot of my own home and auto repairs. I am also a perfectionist. Do you believe that an inexperienced person can effectively rebuild a boat with the help of these forums and some local professional or experienced help from time to time?
Like I mentioned, this boat has sentimental value but it would be valueless if it sinks in the ocean. I really am glad these forums are here. Obviously, people who have already learned the hard way are here to pass on their knowledge.

 

[Scott Danforth]

That would mean that I tear the old wood deck out and use a small hole saw to drill test holes in the stringers? Then, if no rot is found, fill the holes (as mentioned above) and replace the deck then go about engine repair? For the most serious question:
I do feel that I am skilled and do a lot of my own home and auto repairs. I am also a perfectionist. Do you believe that an inexperienced person can effectively rebuild a boat with the help of these forums and some local professional or experienced help from time to time?
Like I mentioned, this boat has sentimental value but it would be valueless if it sinks in the ocean. I really am glad these forums are here. Obviously, people who have already learned the hard way are here to pass on their knowledge.

you only nee a 1/4 or 5/16 drill bit. drill into the transom about 1" deep, about 1" above the hull, near the drain. and a few further out. drill a few in the stringers about 2" above the hull and only 5/8" deep. if your shavings come out light-colored, dry, and smelling like fresh cut wood, you are good to go - fill the holes with marine tex and move on. if the shavings come out dark, wet, and smelling like rotten mulch, pull the motor and drive and start restoring.

 

[CW2cJ]

you only nee a 1/4 or 5/16 drill bit. drill into the transom about 1" deep, about 1" above the hull, near the drain. and a few further out. drill a few in the stringers about 2" above the hull and only 5/8" deep. if your shavings come out light-colored, dry, and smelling like fresh cut wood, you are good to go - fill the holes with marine tex and move on. if the shavings come out dark, wet, and smelling like rotten mulch, pull the motor and drive and start restoring.

Scott, you are a blessing. You make this all sound so easy. Since I cannot see the stringers, am I correct in that I need to pull up the deck, or at least part of the deck? We are going to redo the interior anyway. I stated pulling up the vinyl cover that was over the deck and it is just a plywood deck. I should be able to find screws to remove to lift it up, correct?

 

[Scott Danforth]

Scott, you are a blessing. You make this all sound so easy. Since I cannot see the stringers, am I correct in that I need to pull up the deck, or at least part of the deck? We are going to redo the interior anyway. I stated pulling up the vinyl cover that was over the deck and it is just a plywood deck. I should be able to find screws to remove to lift it up, correct?

The deck should have had fiberglass sealing it.

My guess you will find the plywood over the original deck. Known as a deck-over. The equivalent of a shady used car place filling in rust with duct tape and bondo and givit it an earl scheib paint job.

 

[todhunter]

That would mean that I tear the old wood deck out and use a small hole saw to drill test holes in the stringers? Then, if no rot is found, fill the holes (as mentioned above) and replace the deck then go about engine repair? For the most serious question:
I do feel that I am skilled and do a lot of my own home and auto repairs. I am also a perfectionist. Do you believe that an inexperienced person can effectively rebuild a boat with the help of these forums and some local professional or experienced help from time to time?
Like I mentioned, this boat has sentimental value but it would be valueless if it sinks in the ocean. I really am glad these forums are here. Obviously, people who have already learned the hard way are here to pass on their knowledge.

You can do it. Take a few weeks and watch all of the Frisco Boater videos on YouTube for the Sea Ray restoration he did, and if you want more, watch some of the Boatworks Today videos and JMink's videos on his Glastron restoration as well. I've always been mechanically inclined but fiberglass work seemed daunting before I started. I went all in and started my restoration in September 2020 and should be done with mine by the end of December 2021. Fiberglass work isn't bad at all. It's actually way more forgiving than I thought. I may not be getting perfect resin/glass ratios for the lightest/strongest layups, but what I have done is leaps and bounds better than the boat was originally built.

Being a perfectionist may hurt you a little - you've gotta know when to say it's good enough. Your project may also suffer from scope creep, so triple (or more) your initial cost estimates.