Plz HELP identify my engine model

[scooter4n]

hi all.
I bought 1990 18' open bow Chaparral boat last year.
Now I want to know what engine is in it, model (3.0L or LX) and year, because my mechanic told me that this is not original engine in here, or was rebuild. so I just want to know what I got if you can help me please.

Mecruiser 3.0 liter inline 4
Serial tag on the side of the engine block is missing.
On the cover of the air filter I have;
Engine SN: OC764521
Drive SN: OD317441
I don't this this is original cover.

On the side of the engine under the oil pressure sender I have numbers:
GM 2770087
118 87
On the side of the exhaust manifold I have numbers:
42673C3
22149

Spark plugs are: AcDelco MR43T

please help me.
thank you

 

[Don S]

Re: Plz HELP identify my engine model

It's probably an 89 engine, not unheard of in a 1990 boat from any manufacturer. If you have a January or February boat, it has a better than average chance of having an older engine/drive package.
Anyway, it's NOT an LX. The SN is before the LX models even came out.

This service bulletin might help.

http://www.boatfix.com/merc/Bullet/97/97_06.pdf

 

[scooter4n]

Re: Plz HELP identify my engine model

thanks Don.
but I think that because original Sn was removed from the block, and only thing I have is plastic cover over air filter, I think that SN's are from maybe old engine, and what ever I have now is maybe something different.
but thanks.

another very strange thing, as i was going trough the manual I notice very strange thing, my fuel pump is upside down.
It's is totally opposite way from this picture>> http://img2.freeimagehosting.net/image.php?8341941445.jpg
My reservoir is on the top
Im lost, did some one put that pump upside down and online manual is wrong, LOL
But boat starts and runs grate :0

 

[Don S]

Re: Plz HELP identify my engine model

Use that Service bulletin link I gave you and start matching numbers.

 

[scooter4n]

Re: Plz HELP identify my engine model

what you think about the fuel pump upside down?

 

[Bondo]

Re: Plz HELP identify my engine model

what you think about the fuel pump upside down?

Ayuh,.... They've been build both ways over the years....

You're worrying about Nothing......

 

[scooter4n]

Re: Plz HELP identify my engine model

can someone point me to the right manual for my year and model of the engine please:

Engine SN: OC764521

 

[Bondo]

Re: Plz HELP identify my engine model

Ayuh,.....

This manual, Right Here,....
Is for the 3.0l motor,.... I'm not sure of the vintage,....
But they've changed Very Little over the last 45 years.....

If you want the 1 for Your serial #,.... See your Merc. Dealer......