Advice on a 1970s 140/120 hp Mercruiser

cleanupcobra

Recruit
Joined
Aug 2, 2017
Messages
2
Hi guys, just wanted some info here. I bought a later 70s Delta 17V with a mercruiser 120hp (engine has sticker that says 120hp, but but serial number says this is the 140 model) 4cyl engine with a mercury outdrive. Aesthetically the boat and trailer needed a lot of work, but the engine really just needs a comprehensive tune up. A guy at a boat store told me that this era of mercruiser engines are basically worthless and only worth a couple hundred dollars even in running condition. I feel like he is incorrect, but before I start throwing any money at the engine I wanted to see if anyone can verify what this guy told me about the engine being worthless, and whether or not I should invest any time or money into this engine. I bought this cause I got the boat for a really good price and was mostly looking for a fun, relatively easy project, to be able to put some time in and then flip the boat and hopefully make a little money.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,306
start with a compression test.
then replace points, condensor, etc.

and yes, that motor is only a few hundred in good running condition. you mention that aesthetically the boat and trailer need a lot of work. prior to do any work, verify that your hull isnt rotten. drill a few test drills into the stringers and transom (from the inside). if the wood shavings come out light-colored and dry, then use epoxy to seal up the drill holes and continue. if they come out dark and wet, then sit back and seriously consider that you may have to spend up to $5000 to restore the boat.

the 120 and 140 shared the same serial number batches. look on the side of the block. 2.5 liter is 120hp, 3.0 liter is 140 hp
 

chevymaher

Commander
Joined
Mar 29, 2017
Messages
2,914
Look at it this way if you even need a motor it is practically free. I don't think you will ever find one for that tho. Just the distributor cost that much. I had to fix mine. I would have loved to got a free motor for the price of the distributor. I know I am not finding anybody giving this stuff away. Local or online.
 

CrazyFinn

Petty Officer 1st Class
Joined
Dec 12, 2016
Messages
357
A guy at a boat store told me that this era of mercruiser engines are basically worthless and only worth a couple hundred dollars even in running condition.

Compared to the injected, computer controlled engines in new boats, maybe it's "worthless", but on the other hand, if it runs, and can be kept running for next to nothing (and those engines are easy to work on), it's "worth" what it would cost you to replace it with something else. What was he trying to sell you when he said this (either now or later)?

If you like the boat, that's what is really going to cost you to fix up - any boat from the 70's is going to have more rot and other issues than it appears on the surface. If you really want to fix it up, spend your money on the boat, and power it with the "worthless" engine that you have. And have fun doing it!
 

bbook83

Petty Officer 2nd Class
Joined
Nov 6, 2004
Messages
174
I have had a 1974 Mercruiser 140 in a Jolly Roger ski boat since it was new. I rebuilt the engine in the 80s and have about 800 hours on it since then. I did transom and other fiberglass work recently and replaced gimbal bearing, bellows, hoses, cables and controls, but engine and outdrive internal components are as they have been since the 80s. It doesn't get the hours it used to, but it is going strong and is easy to work on. I would have to agree that one of these isn't worth much, but doesn't mean it isn't worth keeping.

By the way, forget the part about fixing it up and flipping it for a gain. I think many here would agree that ain't gonna happen.
 

CrazyFinn

Petty Officer 1st Class
Joined
Dec 12, 2016
Messages
357
By the way, forget the part about fixing it up and flipping it for a gain. I think many here would agree that ain't gonna happen.

Somehow, I missed this part of the original post.

What he says - forget making money on flipping a boat. You might get your money for materials out of it - if you're lucky - and it's a very desirable model of boat - but you sure won't get your labour paid for. There are just way too many used boats on the market...

Rebuilding a boat is only worthwhile if you are doing it for yourself. You get a solid, rot free, reliable boat for far less (in materials) than what you would have to pay for a NEWER boat that is already in that same condition. It doesn't mean that the resale value of your restored boat is now the same as that newer boat.
 
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