I got got on a new purchase

cjray03

Cadet
Joined
Aug 6, 2023
Messages
24
Hi, I just bought a 1973 Tri Hull "Enterprise" boat. I had told the guy I wanted to hear it turn over before purchase, but somehow I ended up buying it without trying to start it. He told me he drained the oil at the end of last season in the "winterizing" process. I know that draining the oil isn't part of it, but I figured he just didn't know.

Long story short...I got home and took of the filler cap to put oil in it to try and start it and there was significant water/oil mix on the underside of the filler cap, looked like dirty vanilla pudding. I knew immediately he got me.

Now I need a Chevy 250cid inline 6. Either short block or long block. Does anyone know the best place to get one? I have googled and googled and can't really find a good place.
 

Alumarine

Captain
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Feb 22, 2005
Messages
3,734
That could just be the result of condensation.
Have you tried to run it to see if water leaks anywhere or the oil gets contaminated?
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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the motor is going to be the least of your issues.

how is the transom and stringers?

as for the motor, look in salvage yards for a motor to rebuild. and rebuild it. talk to your local engine builder. you are looking for a 1962-1980 chevy 250 with separate head/intake.
 

cjray03

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Aug 6, 2023
Messages
24
The floor and transom are solid. Oh yeah. I tried to turn it over after putting my compression tester in cylinder one...the thing is frozen up. The starter clicked in hard when I first turned the key, then just buzzed after that. I took all the plugs out and tried to turn it around by hand and it's stuck tight. I knew to try and turn the thing over before I bought it, but I just let the guy talk me right by it.

So a later model block will work? I found a short block for $900. I don't know if it's worth it or not. At least it's on a very nice trailer...lol
 

Bondo

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So a later model block will work? I found a short block for $900. I don't know if it's worth it or not. At least it's on a very nice trailer...lol
Ayuh,..... I believe up to 1979 Merc was runnin' 'em,......

That sounds like alot for just the short block, unless a fully rebuilt/ reman. short block,......
You oughta be able to buy a Running Merc used motor outa a rotten hull for 'bout that price,.....
Fully dressed, ready to bolt in, 'n Go,.....

Where are you,..??
 

cjray03

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Aug 6, 2023
Messages
24
I'm just South of Seattle Washington. I'm looking around haven't found anything local yet. I'm gonna keep looking though I really want this boat to run.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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according to google. engine builders in your area.....

S&J in spokane
Autosport in Seattle
Jasper in Seattle
C&D in Kirkland
East Valley Auto rebuild

others......

then you get to the salvage yards
Pick-n-pull in Lynnwood
Yank-a-part in Poulsbo

according to car-part.com, whiteside autowrecking has a motor out of a forklift with good compression

1718098679794.png
 

matt167

Rear Admiral
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Sep 27, 2012
Messages
4,151
I wouldn’t do a thing until I investigated the condition of the engine mounting. You’re not held to a 165 if you have to redo the engine mounting. If it won’t hold a lag bolt it’s gotta get redone, and that’s at a minimum.

If it would hold a lag bolt. I’d build a structure to hold a 140 3.0L as they are everywhere cheap. You loose 20hp but you are on the water until you hate getting beat To death with a tri hull. You will be able to get a prop to work with the different gear ratio.. really doubt the boat is that solid. My guess is your going to find ugly when you tear into it
 

JonBoat55

Seaman
Joined
Aug 26, 2019
Messages
55
If I were you, I might go back to the seller if this boat was listed and sold to you as having a working engine. Yes, you should have checked everything before you bought, as you said. He's under no obligation to give you your money back but that doesnt mean you can't confront him (respectfully) and try to come to some kind of resolution.
If I sold a frozen, ruined engine in a boat described as running, I should expect a rock through my window 😆
 

cjray03

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Aug 6, 2023
Messages
24
Ok, I just found one out of an '80 Camaro. Comes with a bunch of extra parts I won't need...a couple of different intakes 4bbl and 2bbl etc. How hard is it to change these things out? I have done several automotive engine swaps in my time, and I have done quite a bit of work on these Mercruisers...in the boat...and can I upgrade the outdrive while I am doing this? It's a first generation outdrive. Would I have to change the hole in the transom? I don't want to go through all of that I don't think.

Thanks for all the info!
 

cjray03

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Aug 6, 2023
Messages
24
Yeah I did get back to the guy via offerup the way I purchased it. He just said "oh well that's news to me, it was running when I parked it" complete bologny, but I got no real recourse. Yeah I'll tear into the mounting and check the floor better, seems solid, but I'll look further. I have had a couple of the 3.0s and a 2.5, did quite a bit of work on them. At any rate I'll do further investigation into the stability of the whole boat.
 

matt167

Rear Admiral
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Yeah. You will need to drill 2 new holes and open up the opening in a couple spots. Best to use a rotted glass boat transom skin for a template. At least that’s one way to do it. If you are going to that trouble, do the work for a 4.3L swap. The straight 6 will need a different manifold or riser I think to work on a later drive. And for sure won’t work with a gen 2 drive. You could do Alpha gen 1 pretty cheaply
 

Scott Danforth

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Ok, I just found one out of an '80 Camaro. Comes with a bunch of extra parts I won't need...a couple of different intakes 4bbl and 2bbl etc. How hard is it to change these things out? I have done several automotive engine swaps in my time, and I have done quite a bit of work on these Mercruisers...in the boat...and can I upgrade the outdrive while I am doing this? It's a first generation outdrive. Would I have to change the hole in the transom? I don't want to go through all of that I don't think.

Thanks for all the info!
you will need to pull the motor apart, knock out the steel core plugs and change to brass

you will need to pull the head and change the steel head gasket to a marine one

you will need to pull the cam and install a marine cam (with new lifters). the car cam has too much overlap for a wet manifold. the truck cam would have been fine

none of the extra stuff coming with the motor can be used on a boat motor. sell them on ebay.

if you want to change the outdrive, then I would simply suggest abandoning the 250 cubic inch inline 6 and get a complete 1996 or newer 4.3 V6 and outdrive from a boat and swap over. no sense sticking with a supper heavy inline 6 and going thru all that work for a much lighter and more powerful 4.3
 

cjray03

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Aug 6, 2023
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OK, thanks guys. Just yesterday my wife suggested that I pull the 4.3 from the Bluewater that I bought last year. Got the boat and trailer for $200, just had to change the fuel pump and rebuild the carb and it runs like a champ. But the interior and floor is shot in it. We've been using it as is. I haven't had time to get out there and bang around on the transom and floor on the one with the inline 6 yet though. I'll be able to inspect it better on Sunday.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Any fiberglass boat before 2002 should be considered full of rot

Post 2002, most have stringer tubs glued together with methacrylate. Those have flex-crack issues at the glue joints

Your 52 year old tri-hull will most likely have a rotten transom and stringers
 

nola mike

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Apr 22, 2009
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5,363
OK, thanks guys. Just yesterday my wife suggested that I pull the 4.3 from the Bluewater that I bought last year. Got the boat and trailer for $200, just had to change the fuel pump and rebuild the carb and it runs like a champ. But the interior and floor is shot in it. We've been using it as is. I haven't had time to get out there and bang around on the transom and floor on the one with the inline 6 yet though. I'll be able to inspect it better on Sunday.
This sounds like the obvious answer, again assuming the new boat is solid. You could upgrade the drive then as well. Don't bang around. Drill core samples, especially transom around the key hole and any penetrations, and the stringers (esp near the stern) and mounts. May or may not want to pull the motor first if it's coming out anyways.
 

Scott06

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Apr 20, 2014
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6,440
OK, thanks guys. Just yesterday my wife suggested that I pull the 4.3 from the Bluewater that I bought last year. Got the boat and trailer for $200, just had to change the fuel pump and rebuild the carb and it runs like a champ. But the interior and floor is shot in it. We've been using it as is. I haven't had time to get out there and bang around on the transom and floor on the one with the inline 6 yet though. I'll be able to inspect it better on Sunday.
You could do that but only makes sense if the stringers and transom are good. Likely will need new engine stringers for the side mount on the 4.3 vs the front mount on the straight six.
personally I think you would be better off finding a more recent boat with a cracked block or dead engine to put your 4.3 in. thats what I did a few years back bought a boat that PO cracked the block in.
 

garbageguy

Lieutenant Commander
Joined
May 8, 2012
Messages
1,574
yes, and does a tri-hull meet your boating wants (for this boat)? I'd consider that before putting too much work into it. Maybe it does.
 
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