Pre-Alpha Visual Identification Resources

[wxkl]

Hi all,
I have a pre-alpha mercruiser, and I would like to "officially" ID it because I need to buy parts and I want to make sure I'm buying compatible parts.
I'm pretty sure its an MC-1, but it's been replaced in the past and I'm not 100% sure that the serial number I have on the paper is accurate, and I'm having trouble reading the actual number
Is there some resource that offers a better guide that doesn't require a SN? Like some visual cues that will help me figure out which specific prealpha I have?
Or... barring this, what should my confidence level be when buying general "prealpha" components that most of them will be interchangable?

Thanks!!

 

[nola mike]

Miscellaneous Mercruiser Information

How to ID an Alpha Style Outdrive, and History. Mercruiser Alpha ID and History.pdf - 4shared.com - document sharing - download - Don S Explainer documents. 'Pre-Alpha' drives Which 'Pre-Alpha' drive? Where to Find Mercruiser Stern Drive and Engine serial numbers. Drive units In-line Engines...

forums.iboats.com

 

[achris]

Where to find Mercruier Stern Drive and Engine serial numbers.

Stern Drive serial numbers. (Continue down to the next posts for engine locations) ---------------------------------------------------------------------------------------------- All Mercury Marine serial numbers follow a particular format, be they Engine, Drive or Gimbal housing. Up to about...

forums.iboats.com

 

[wxkl]

Where to find Mercruier Stern Drive and Engine serial numbers.

Stern Drive serial numbers. (Continue down to the next posts for engine locations) ---------------------------------------------------------------------------------------------- All Mercury Marine serial numbers follow a particular format, be they Engine, Drive or Gimbal housing. Up to about...

forums.iboats.com

Thanks! I thought that the serial number was unreadable, but the link you shared seems to imply that there are multiple serial numbers on the outdrive.... unfortunately, I can't see the image, so I can't tell what's going on. But if there is another location with a SN that I could check, that'd be great! Any chance you have a different version of the image showing SN locations? Thanks!!

 

[wxkl]

Miscellaneous Mercruiser Information

How to ID an Alpha Style Outdrive, and History. Mercruiser Alpha ID and History.pdf - 4shared.com - document sharing - download - Don S Explainer documents. 'Pre-Alpha' drives Which 'Pre-Alpha' drive? Where to Find Mercruiser Stern Drive and Engine serial numbers. Drive units In-line Engines...

forums.iboats.com

Thanks! I've gone through this thread, but a lot of it requires a SN which I don't think is mostly legible on mine (but maybe there's another location with the SN, which would be awesome). Am I missing a visual guide in there? thanks!!

 

[Bondo]

Hi all,
I have a pre-alpha mercruiser, and I would like to "officially" ID it because I need to buy parts and I want to make sure I'm buying compatible parts.
I'm pretty sure its an MC-1, but it's been replaced in the past and I'm not 100% sure that the serial number I have on the paper is accurate, and I'm having trouble reading the actual number
Is there some resource that offers a better guide that doesn't require a SN? Like some visual cues that will help me figure out which specific prealpha I have?
Or... barring this, what should my confidence level be when buying general "prealpha" components that most of them will be interchangable?

Thanks!!

Ayuh,..... What sorta "Parts",..??..??

 

[wxkl]

Ayuh,..... What sorta "Parts",..??..??

Well... I have it down to the transom plate right now, and I'm putting it back together and basically replacing anything and everything that I can find as I go and as things look old/corroded... so I'm not 100% sure what I'll end up needing, but I know I'll be needing parts (at least things like gaskets) so I'd like to make sure I can check compatibility.
Also, just in general, I'd like to know what model I have so that I can ask better questions here

 

[Alumarine]

There used to be a pictorial showing the differences but did you see this?

 

[achris]

Thanks! I've gone through this thread, but a lot of it requires a SN which I don't think is mostly legible on mine (but maybe there's another location with the SN, which would be awesome). Am I missing a visual guide in there? thanks!!

Yes, there are plenty of pictures. If you can't see them, check to make sure your ISP or browser isn't blocking 'iinet.net.au'.

Here's the picture associated with MC1 serial number.

 

[wxkl]

@Alumarine @achris thank you! I'm sure those photos will help... no idea why I'm not seeing the photos.

Just curious... are the serial numbers carved/stamped into the metal, or are they actually on the decals? Because I'm not seeing anything in any of those locations. I see that there used to be decals there, but there's nothing stamped into the metal in those locations. If all of my decals are gone, will I still be able to find a SN?

Thanks!

 

[achris]

If the drive is a replacement, then there will not be a serial number on the housing on the left side where the decal would be. (The originals had the number stamped into the metal). You just have to identify it visually, and go from there.

If you post up photos of the drive, the transom gimbal housing and the inner transom plate, we should be able to give you a range for the serial number. We'd be looking for things like the hinge pins on the gimbal ring, the shape of the cav plate on the drive, the style of the top cover on the top of the drive. Even the shape of the trim rams and where the hydraulic pipes run and are connected, all helps narrow it down. Photos from different angles, and details...

Chris......

 

[wxkl]

If the drive is a replacement, then there will not be a serial number on the housing on the left side where the decal would be. (The originals had the number stamped into the metal). You just have to identify it visually, and go from there.

If you post up photos of the drive, the transom gimbal housing and the inner transom plate, we should be able to give you a range for the serial number. We'd be looking for things like the hinge pins on the gimbal ring, the shape of the cav plate on the drive, the style of the top cover on the top of the drive. Even the shape of the trim rams and where the hydraulic pipes run and are connected, all helps narrow it down. Photos from different angles, and details...

Chris......

Thank you. Here is an album with the whole outdrive and then photos of the gimbal housing, etc with the drive part off.
It must be a replacement... I don't see numbers!

Album with images: https://app.photobucket.com/u/wxkl/a/bf7bb0ef-71bc-48f9-9248-8daa499d1428

Thanks

 

[achris]

Had a look at your photos. Wow, what a mashup of parts!

Gimbal housing appears to be in the 1967-1974 era.
(I believe you found it had a Circlip holding the gimbal bearing in, which would make it 1967 -1969)

You have one Prestolite series one trim ram (port side) and a prestolite series III on the starboard side.

The screws holding the drive top cover are WRONG! I see cross-head screws,

they are supposed to be 12-point screws.

Those screws need to be torqued quite accurately to get the correct pre-load on the bearings. You can't get that with cross-head screws. (not your fault, I know)

Chris.....

 

[wxkl]

Had a look at your photos. Wow, what a mashup of parts!

Gimbal housing appears to be in the 1967-1974 era.
(I believe you found it had a Circlip holding the gimbal bearing in, which would make it 1967 -1969)

You have one Prestolite series one trim ram (port side) and a prestolite series III on the starboard side.

The screws holding the drive top cover are WRONG! I see cross-head screws,
View attachment 341412
they are supposed to be 12-point screws.
View attachment 341413
Those screws need to be torqued quite accurately to get the correct pre-load on the bearings. You can't get that with cross-head screws. (not your fault, I know)

Chris.....

wow... guess I'm not shocked, it seems like it might be a mashup of parts

I definitely did ask about a clip holding the gimbal bearing in, but after showing some photos, the conclusion was that there is not a clip in there. But there is a groove for a clip, if that helps narrow down the year!

I think I'm mostly trying to narrow down the model... I suspected it was an MC-1, but I am not 100% sure. Although maybe now is the time to ask a tough question, which is... considering what a mashup of parts this is, and how old it is, and how I'm looking at replacing a lot of it... maybe it's best to just get a new outdrive?
Clearly, you saw my post about how my gimbal bearing is really, really stuck in the housing, and is basically welded to the housing from corrosion... perhaps I should think about just replacing everything from the gimbal housing on back? If so, how do I know what outdrive models are compatible with my motor? I still have my old outdrive so I can check gear ratios, but in terms of even just taking the first step of "buying a new gimbal housing," how do I know which model will fit on my transom plate?

Thanks!

 

[achris]

Ok, yes, it most definitely is an MC1.

Replacing. MC1 finished in 1982 (basically, 40 years ago!) And given yours is an 'early' MC1, the bolt holes on the inner plate don't match anything later than ~1975. Merc modified the inner plate for the later MC1s (~1976 to 1982) and the bolt pattern is the same as the later gimbal housings (1983-1990) so in theory you could use an Alpha One gimbal housing with a later MC1 inner transom plate and have the engine mount properly. When Merc introduced the R (and later the MR and Alpha One) the rear engine mount spacing changed (from 14" to 10"), so getting an Alpha One gimbal housing and inner plate will leave you with and engine that won't sit on the inner plate mounting points.

I haven't seen anywhere you call out what engine you have. Some engines never made it to 1983, so getting a flywheel housing to match the later (1983+) mountings for some engine isn't possible.

Welcome to the nightmare that is, FrankenMerc! (And why we so desperately avoid doing anything like that!)

Chris.....

 

[wxkl]

Hi Chris,
First, thank you for all the information you've provided so far, I really appreciate you sharing your knowledge.
My motor is a 165hp GM Inline-6 from the late 60s. so if I'm understanding properly, I can get any gimbal housing up until about 1975 and it should be compatible with my inner transom plate? And then I can either use the FrankenMerc setup that I have now and replace parts, or find a compatible drive component and just replace the whole thing?

Are there good sources for these older parts, or is it just a matter of scouring ebay? The only thing I see on ebay that looks even remotely similar is this one: https://www.ebay.com/itm/233999301792 but there is no year on it and it has "wings" that mine doesn't have.

Just curious—are there any better options? Like, would it be better and is it fairly easy to somehow convert away from a pre-alpha and get rid of the whole frankenmerc thing in favor of getting a more modern alpha or similar? Or is that just a huge headache. What do most people with frankenmercs do?
Thanks!!

 

[achris]

Yeah, those 'wings' are gimbal ring mounted trim senders, and what differentiates the early MC1 from the later MC1. And the inner transom plates between the 2 are not compatible.

I was in your position 27 years ago with a 1972 165. The gimbal housing was badly corroded and the drive had a cracked gear. Fix, replace like for like or re-power? Fix or replace left me in the same position, an old and unreliable package. Not what you really want when you're 30 miles out to sea! I opted for re-power, to a brand new 4.3LX. Best move I ever made.

You're a little more fortunate, as you live in a place where good quality second hand packages are easily available. (I didn't have that option where I live)... If it were me, I'd look for a V6 (4.3L) in the 10 to 15 year age mark. That gimbal housing and drive are still current (known as an Alpha One Gen II), and engine parts are far easier and cheaper for the 4.3 than the old inline 6... Good power packages can be got from rotted out hulls, like Bayliners...

If you want to go down the 'replace like for like' path, it's going to be a more difficult journey. Finding the right parts, in good condition for something that they stopped making almost 50 years ago isn't going to be easy.

Chris....

 

[wxkl]

Yeah, those 'wings' are gimbal ring mounted trim senders, and what differentiates the early MC1 from the later MC1. And the inner transom plates between the 2 are not compatible.

I was in your position 27 years ago with a 1972 165. The gimbal housing was badly corroded and the drive had a cracked gear. Fix, replace like for like or re-power? Fix or replace left me in the same position, an old and unreliable package. Not what you really want when you're 30 miles out to sea! I opted for re-power, to a brand new 4.3LX. Best move I ever made.

You're a little more fortunate, as you live in a place where good quality second hand packages are easily available. (I didn't have that option where I live)... If it were me, I'd look for a V6 (4.3L) in the 10 to 15 year age mark. That gimbal housing and drive are still current (known as an Alpha One Gen II), and engine parts are far easier and cheaper for the 4.3 than the old inline 6... Good power packages can be got from rotted out hulls, like Bayliners...

If you want to go down the 'replace like for like' path, it's going to be a more difficult journey. Finding the right parts, in good condition for something that they stopped making almost 50 years ago isn't going to be easy.

Chris....

OK... thanks... have some thinking to do. I may want to replace like for like while I hunt down the proper re-power motor/outdrive (who makes the 4.3, is that still a GM or is it mercruiser?).

Just to get me back on the water... does this look like the right drive? https://www.ebay.com/itm/194073414886

If it's $850 shipped, that might be worth it if it lasts even a year, as it may take me that long to get ready to repower... I'd want to do things like replace the transom, etc. if repowering, I bet.

Thanks!

 

[achris]

OK... thanks... have some thinking to do. I may want to replace like for like while I hunt down the proper re-power motor/outdrive (who makes the 4.3, is that still a GM or is it mercruiser?).

The 4.3 engine is a GM (basically a 350 with 2 cylinders removed). MILLIONS of them out there in auto-land.

Just to get me back on the water... does this look like the right drive? https://www.ebay.com/itm/194073414886

That drive looks like the same vintage as what you have.

Any drive up to 1990 will fit, just need to be sure to get the right ratio. You would have to change the input yoke to the shorter one (8-1/2" I think, something like that). All inline engines up to 1983 ran the shorter and V engines ran the longer (again, I think, 9-5/8"). From 1983 on, all engines use the longer yoke.

 

[nola mike]

OK... thanks... have some thinking to do. I may want to replace like for like while I hunt down the proper re-power motor/outdrive (who makes the 4.3, is that still a GM or is it mercruiser?).

Just to get me back on the water... does this look like the right drive? https://www.ebay.com/itm/194073414886

If it's $850 shipped, that might be worth it if it lasts even a year, as it may take me that long to get ready to repower... I'd want to do things like replace the transom, etc. if repowering, I bet.

Thanks!

Wow. That's bananas expensive. Look for an a1g1 drive, they're plentiful around here for around $250. Or buy a junk boat for <$1k. You'd be ahead just selling the trailer and pulling the drive. Where are you located?