Mercruiser engine year help

[orthoguy]

I was finally able to download the Mercruiser manual for the year of my boat, but the engine serial numbers it covers doesn't include my boat....must have a year older engine?

Can anyone cross reference the serial # 3084255

I need to order a new water pump repair kit and I want to make sure I buy the correct one....there are no numbers on the outdrive so I'm not sure what that is either.

Thanks in advance!

Mike

 

[achris]

Re: Mercruiser engine year help

Mike,

Under the decal on the port side of the upper section you'll find the serial number stamped into the housing....

I have used your serial number in my Merc program and it doesn't come up with anything... What is the engine? And where exactly did you find that number?

Chris.........

 

[orthoguy]

Re: Mercruiser engine year help

Mike,

Under the decal on the port side of the upper section you'll find the serial number stamped into the housing....

I have used your serial number in my Merc program and it doesn't come up with anything... What is the engine? And where exactly did you find that number?

Chris.........

Yeah I just tried looking at the stamped # it's so worn down and painted over I can't make it out...something like 307101 307181 I know there are supposed to be 7 #'s but I can't make them out

I found the engine serial # on the starboard side (plug side) rear part of the engine 250 6 cyl. 165

Let me go double check that # again

 

[achris]

Re: Mercruiser engine year help

The 308.... part of it makes it look like 1971.... If you can post a photo of the transom housing, near the hinge pins, I'll have a better idea if I'm in the right era.

It looks like manual# 1 is the one you want... It's a biggy! 1.3GB!!

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

 

[orthoguy]

Re: Mercruiser engine year help

The 308.... part of it makes it look like 1971.... If you can post a photo of the transom housing, near the hinge pins, I'll have a better idea if I'm in the right era.

It looks like manual# 1 is the one you want... It's a biggy! 1.3GB!!

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

Yep the engine decal reads: 3084255
Outdrive possibly:
3071043

pics enclosed

 

[orthoguy]

Re: Mercruiser engine year help

The 308.... part of it makes it look like 1971.... If you can post a photo of the transom housing, near the hinge pins, I'll have a better idea if I'm in the right era.

It looks like manual# 1 is the one you want... It's a biggy! 1.3GB!!

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

So I have an even older drivetrain than the boat itself....Nice! I have been buying 1974 parts when I did the engine repair....so far everything worked!

 

[orthoguy]

Re: Mercruiser engine year help

It looks like manual# 1 is the one you want... It's a biggy! 1.3GB!!

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

Oh that's just great! It took me 5 attempts to download the 1974 manual....kept timing out!

 

[achris]

Re: Mercruiser engine year help

Oh that's just great! It took me 5 attempts to download the 1974 manual....kept timing out!

I'm having the same problem with it as you...

By the photos, I have the year about right... An early MC-1... The good news... That lower gear housing is a later model... Somewhere '83/'84 (making it an 'R')... Don't worry, the parts (except the housing itself) are all the same....

Chris..........

Edit... Just noticed you have a flat top upper... Hmmm, that's not right!!! The upper (minus the top) is definitely early (1971)... but someone has put an 'R' top on it....

 

[orthoguy]

Re: Mercruiser engine year help

I'm having the same problem with it as you...

By the photos, I have the year about right... An early MC-1... The good news... That lower gear housing is a later model... Somewhere '83/'84 (making it an 'R')... Don't worry, the parts (except the housing itself) are all the same....

Chris..........

Edit... Just noticed you have a flat top upper... Hmmm, that's not right!!! The upper (minus the top) is definitely early (1971)... but someone has put an 'R' top on it....

So I buy a water pump kit for a 1971?

So I basically have a Frankenstein stern drive? LOL, nice! All I know is it works great!

 

[achris]

Re: Mercruiser engine year help

No, the water pump is part of the gear housing... So, buy a 1983 one of those... But they are all the same from about 1970 to 1984...

And it's a Mercenstein... Don't worry too much... most of the parts are the same, or supersede to the same part....

Chris.......

 

[orthoguy]

Re: Mercruiser engine year help

No, the water pump is part of the gear housing... So, buy a 1983 one of those... But they are all the same from about 1970 to 1984...

And it's a Mercenstein... Don't worry too much... most of the parts are the same, or supersede to the same part....

Chris.......

OK, thanks buddy....I am at 97% download and crossing my fingers

 

[orthoguy]

Re: Mercruiser engine year help

Manual downloaded. It still will not state a specific year but everything looks the same as far as the engine.

My #'s aren't even listed just states all 377 prefix and below...So It's just a pre '74 something. LOL.

I need to change my screen name to "FrankenStern"

Mike

 

[orthoguy]

Re: Mercruiser engine year help

Chris...

So in the iboats Marine store, I need kit # 18-3317?

Thanks!

 

[achris]

Re: Mercruiser engine year help

Chris...

So in the iboats Marine store, I need kit # 18-3317?

Thanks!

Yep!!!

 

[orthoguy]

Re: Mercruiser engine year help

Yep!!!

Thank you, Sir

Frank

 

[orthoguy]

Re: Mercruiser engine year help

Well, it looks like I bought the wrong kit. Everything is exactly the same except for the pump base. Actually the gasket I received for the pump base is the same but the bottom of my new pump is different than the old one, a little different shape, but everything lines up properly, but the biggest difference is the old one has a big Blue plastic ring on the bottom and the new one does not.

After looking back at all the water pump kits, it looks like I need kit # 18-3320 not 18-3317. I now see a footnote that states drives without a preload pin take the 18-3320 kit....I didn't know that I didn't have the preload pin until last night.

Am I right about the wrong kit, or is this just a newer design now?

Mike

 

[orthoguy]

Re: Mercruiser engine year help

Disregard question....I just found the correct base at a marina store.

 

[achris]

Re: Mercruiser engine year help

If you don't have a pre-load pin on the top of the drive shaft, then you have an MR or Alpha One lower unit... That really is a Mercenstein!!! The lower unit is between 1985 and 1990... There are significant differences between what we thought it was and what it actually is... And you need this manual for it...

Service Manual #6 R, MR, Alpha I outdrives 1983 to 1990
Must open each section individually to save.
http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/6/6covr3.pdf

My humble apologies for getting you the wrong part....

Have a look at the end of the propeller shaft... If you see a letter 'A' stamped in the end, then it's an early MR... If not, it a later MR or Alpha One....

(Wouldn't have picked THAT on a 1971 engine!!!)

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

 

[orthoguy]

Re: Mercruiser engine year help

If you don't have a pre-load pin on the top of the drive shaft, then you have an MR or Alpha One lower unit... That really is a Mercenstein!!! The lower unit is between 1985 and 1990... There are significant differences between what we thought it was and what it actually is... And you need this manual for it...

Service Manual #6 R, MR, Alpha I outdrives 1983 to 1990
Must open each section individually to save.
http://www-alt.mercurymarine.com/mnetdata/SERVICE/CRUISER/Servmanl/6/6covr3.pdf

My humble apologies for getting you the wrong part....

Have a look at the end of the propeller shaft... If you see a letter 'A' stamped in the end, then it's an early MR... If not, it a later MR or Alpha One....

(Wouldn't have picked THAT on a 1971 engine!!!)

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

Oh no, here we go again! Yes there is an "A" stamped on the end of the prop shaft. But the parts I needed so far, have been Alpha. I read somewhere else that if it's an MR, that certain parts may be for an Alpha.....so I am still in the dark. Whatever I need in the future I am just going to take the part off first, then buy a new one!

Like today putting the water pump back together, after I went and bought the correct base. I am wondering why there isn't some sort of seal in the upper water pump body where the driveshaft exits?? Does the impeller seal it from the inside then when you install the centrifugal slinger over the pump housing that is enough of a seal? I noticed on the old cover there seemed to be some sort of seal, but it was hard to tell because it had so much melted rubber on it from the old impeller. I hope all is right! Plus the manual stated that "Late drive units do not have oil seal in water pump body"

As for the pin...there is a hole for one, but no pin in it......don't tell me it's lodged in the upper case and I really should have one!

No worries, Chris, about which water pump kit I initially purchased!! I used all the parts except for the base anyway!

Mike

 

[achris]

Re: Mercruiser engine year help

.... I am wondering why there isn't some sort of seal in the upper water pump body where the driveshaft exits?? Does the impeller seal it from the inside then when you install the centrifugal slinger over the pump housing that is enough of a seal? ...

Yes, on the top of the impeller, around the hub, is a raised ring... That seals on the inside of impeller housing..

As for the pin...there is a hole for one, but no pin in it......don't tell me it's lodged in the upper case and I really should have one!

Have a look at the area under the water pump base... Do you see just a cover and a water cavity... Then you should NOT have a pin...

The 'A' on the end of the prop shaft makes it an early MR (around 1985). All parts for Alpha will be correct...

Chris..........