Can someone identify the year model?

[kingoftex]

I have a 140 hp Mercruiser SN 3888092 and I've only been able to narrow the year model down to somewhere between 1968-1982. Pretty Wide range.......I think it is a '73 or '74. Can anyone identify the year for me?

Thanks.

 

[Bondo]

Re: Can someone identify the year model?

Ayuh,....

What Year boat is it in,..??

 

[Don S]

Re: Can someone identify the year model?

The SN you posted is not a good serial number. Merc numbers only had 6 numbers in them for the older models, then the newer models went to 8 characters, staring with a 0 then a letter and 6 numbers.

 

[kingoftex]

Re: Can someone identify the year model?

Don,

It does have 7 digits. Stamped on a Mercury Marine tin tag at the back of the motor. I had searched online and found a site that had some help and it did show 140's to have 7 digits, but only narrowed it down between '68 and '82 (http://www.obparts.com/years/mercruiser1.html). They call it a GM engine, but it is listed under the Mercruisers.

Am I off base somewhere?

 

[Bondo]

Re: Can someone identify the year model?

Ayuh,...

Those motors have changed Very little between those years,....

Just What's the Problem,..??

 

[kingoftex]

Re: Can someone identify the year model?

Bond-o,

I want to put that motor into a different boat. The boat that I want to put it in is a 1988 Wellcraft. I was trying to get as accurate of information as possible before starting to ask my actual question(s). The Wellcraft has a motor that needs to be overhauled, but has a good head that has been milled and a valve job, but is from a 120 hp, 2.5 liter engine. Can I put that head onto the 140 hp, 3 liter engine? What is the actual difference that makes the 2.5 different from the 3? If I can do that, I have a newer head(doesn't need hardened seats put in), manifold and carb. And the linkages from the Wellcraft will attach correctly. That is what I'm trying to figure out.



Thanks.

 

[achris]

Re: Can someone identify the year model?

Although the head will bolt up, it is different. Valve sizes, chamber volume, etc...

That serial number is coming up as 1972 in my books....

Chris............

 

[Bondo]

Re: Can someone identify the year model?

What is the actual difference that makes the 2.5 different from the 3?

Ayuh,...

Both the Bore,+ the Stroke are larger in the 3.0l....
153cid, Vs. 181cid....

Yes,...
The head will bolt on, but you might run into Extra High Compression ratios...
And,..
As noted by Chris,... Smaller Valves...

Btw,...
Basically,...
The 3.0l should be a Plug & Play with the 2.5l.....

 

[achris]

Re: Can someone identify the year model?

.....
Btw,...
Basically,...
The 3.0l should be a Plug & Play with the 2.5l.....

I think he was hoping to use the 2.5 head on the 3.0l block since he's had a lot of work done on the 2.5 head....