Mercruiser model 1A/1B/1C Trim pump

Chef Treff

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Ok guys, I've got a good one maybe you can answer! I recently bought a 1965 Starcraft Holiday 18 project with what I believe to be a model 1A/1B/1C EZ shift outdrive. Originally the boat had the 110HP Iron Duke 4 in it but the guy I bought it from refitted it with a 1970 3.0 due to the 110 being locked up. So here's my question. It has the very old high pressure/low volume tilt pump with a single hydrolic line that splits in the housing to each ram. The rams themselves only have 1 line going to them. I'd like to upgrade the pump but there is zero info on this old style pump and all the newer pumps are high volume/ low pressure with 2 hydrolic lines. What are my options?
Thanks in advance!
 

Scott06

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Ok guys, I've got a good one maybe you can answer! I recently bought a 1965 Starcraft Holiday 18 project with what I believe to be a model 1A/1B/1C EZ shift outdrive. Originally the boat had the 110HP Iron Duke 4 in it but the guy I bought it from refitted it with a 1970 3.0 due to the 110 being locked up. So here's my question. It has the very old high pressure/low volume tilt pump with a single hydrolic line that splits in the housing to each ram. The rams themselves only have 1 line going to them. I'd like to upgrade the pump but there is zero info on this old style pump and all the newer pumps are high volume/ low pressure with 2 hydrolic lines. What are my options?
Thanks in advance!
I would say good luck on this . My grandfather had a '66 Penn Yan with same drive but the 150 hp 6 cylinder, Quite frankly the tilt never worked since it was new, always had issues. I cut my boat maintenance teeth on that boat with him

This is pushing my memory back but originally his had a white pump that took atf , later replaced with a metal black pump that took 10 w oil. I think this pump came off an MC-1 but it must have only had tilt not trim with the later 3 button switch.


I think this is the parts list you need from the later 67-69 MC1 the early ones had tilt only and the pump should work for your application

list both tilt and tilt/Trim systems

Hydraulic system should basically match yours


Pump assy

Unfortunately most parts are not available but with the part numbers you may find used on ebay etc ?

What is the pump doing or not doing? Did you maybe consider taking it to a hydraulic repair shop and see if they can rebuild it? I think brushes in the motor are replaceable ...

I know this isn't what you want to hear but If you really like the boat and want to keep it best bet would be to find a alpha gen one or newer transom and drive tear out and swap it all over so you can get parts
 

achris

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You need to change the rams, pump, all the lines and the manifold under the gimbal housing. Given its now over 50 years since most of those bolts have moved, you'll probably break off more than you undo.

Chris...
 

Scott06

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I think the manifold is not under the gimbal housing hoses come out the side of the gimbal housing 1656604388218.png
 

Chef Treff

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I would say good luck on this . My grandfather had a '66 Penn Yan with same drive but the 150 hp 6 cylinder, Quite frankly the tilt never worked since it was new, always had issues. I cut my boat maintenance teeth on that boat with him

This is pushing my memory back but originally his had a white pump that took atf , later replaced with a metal black pump that took 10 w oil. I think this pump came off an MC-1 but it must have only had tilt not trim with the later 3 button switch.


I think this is the parts list you need from the later 67-69 MC1 the early ones had tilt only and the pump should work for your application

list both tilt and tilt/Trim systems

Hydraulic system should basically match yours


Pump assy

Unfortunately most parts are not available but with the part numbers you may find used on ebay etc ?

What is the pump doing or not doing? Did you maybe consider taking it to a hydraulic repair shop and see if they can rebuild it? I think brushes in the motor are replaceable ...

I know this isn't what you want to hear but If you really like the boat and want to keep it best bet would be to find a alpha gen one or newer transom and drive tear out and swap it all over so you can get parts
Right on, thanks for the reply! So yes, I am aware of the limitations of this outdrive, lack of parts etc, however...lol I do have 2 fully functioning outdrives as well as 2 fully working tilt pumps and I have seen the links you provided and I will admit that while I'm just a recruit here, I was a Mercruiser certified tech for a time a few years ago and I can fix or fabricate mostly anything in my personal shop at my house so I'm not above "Frankensteining" a newer pump system with rams etc that will allow for trim functions as well. I will also admit that while I have extensive experience with the model 165 outdrive I had in another boat (it had the 165 inline 6) I refreshed years ago, I haven't even heard of this model outdrive. My first clue I was in trouble was when I saw the manual reverse lockout..lol. Anyway, thanks for the good info and I will probably just upgrade to an alpha 1 off another project boat and sell the stuff I have.
1 more thing..this is a pic of the pump which I believe to pre-date the pump schematics you sent!
Thanks again!20220626_103449.jpg
 

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Bondo

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Probably so, but it's in pretty good shape. I'll probably go with a complete Alpha 1 conversion
Ayuh,.... Welcome Aboard,..... I think that would be a very wise decision,....

Zero parts for those drivelines,....
Yer parts might be valuable to someone doin' a "Historical" restoration,....
 

Chef Treff

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Ayuh,.... Welcome Aboard,..... I think that would be a very wise decision,....

Zero parts for those drivelines,....
Yer parts might be valuable to someone doin' a "Historical" restoration,....

Rajah that..."valuable" or not is of little interest..I just like projects, keeps me outta trouble and way from the dang ole moving picture box..lol. Anyway, glad to be back on board..it's been a few years...
 

Scott06

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Right on, thanks for the reply! So yes, I am aware of the limitations of this outdrive, lack of parts etc, however...lol I do have 2 fully functioning outdrives as well as 2 fully working tilt pumps and I have seen the links you provided and I will admit that while I'm just a recruit here, I was a Mercruiser certified tech for a time a few years ago and I can fix or fabricate mostly anything in my personal shop at my house so I'm not above "Frankensteining" a newer pump system with rams etc that will allow for trim functions as well. I will also admit that while I have extensive experience with the model 165 outdrive I had in another boat (it had the 165 inline 6) I refreshed years ago, I haven't even heard of this model outdrive. My first clue I was in trouble was when I saw the manual reverse lockout..lol. Anyway, thanks for the good info and I will probably just upgrade to an alpha 1 off another project boat and sell the stuff I have.
1 more thing..this is a pic of the pump which I believe to pre-date the pump schematics you sent!
Thanks again!View attachment 364404
Yes that is the original style pump (takes ATF) that my grandfather replaced with the one i linked to which worked just drive would sink down over sevral minutes…
i assumed you needed a replacement But sounds like that isnt the case. if you do that later tilt pump which is black will work…

merc only made this drive for about 3 years before it completely revised the design and came out with what was the first mc-1 drives (similar to your 165). The mc1 was around for over a decade, given this was mercs first drive and its short life i suspect merc cut their engineering teeth.

i started helping my grandfather with his Penn Yann In the mid eighties so it was older by then. Your thread brought a lot of memories of that boat back. Learned a lot on it, but my grandfather had mentioned never had an issue with the engine, but the outdrive and tilt never really worked right…

if you have the parts and dont mind wrenching probably will work ok, but your on the right path upgrading to a alpha when you can find a decent tear out. You will have some swapping with the cover and coupler as rear mount spacing changed in 81 or 82 when the mc1 was replaced by the R drive. I. Sure some of the guys here like Bondo will know what you have to mix and match
 

Chef Treff

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Alrighty guys, I purchased a complete Alpha 1 gen 1 assembly to swap out this old 65-66 1A/1B/1C assembly. My next question is...drumroll. will my older outdrive bolt up to the newer Alpha assembly? I've had mixed responses elsewhere and I'm wondering what you guys think.
 

Bondo

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Alrighty guys, I purchased a complete Alpha 1 gen 1 assembly to swap out this old 65-66 1A/1B/1C assembly. My next question is...drumroll. will my older outdrive bolt up to the newer Alpha assembly? I've had mixed responses elsewhere and I'm wondering what you guys think.
Nope,.... That ole drive is a beast all it's own,.....
 

Chef Treff

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I didn't get an Alpha Outdrive just everything else....crap.
The guy I bought this from has about 40 boats on his property he parts out so I can go back and get one I'm sure.
Thanks guys
 

Scott06

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I didn't get an Alpha Outdrive just everything else....crap.
The guy I bought this from has about 40 boats on his property he parts out so I can go back and get one I'm sure.
Thanks guys
Alpha one gen one / R//MR or earlier mc1 drive will fit that transom

Alpha one gen one went out of production on 1990 so would be the newest that would fit
 

Chef Treff

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So my guy only has some V6 outdrives which I think are 1.65/1 but my current outdrive is 1.98/1 I think. Is that too much to make up with prop pitch?
The boat is a 65 Starcraft aluminum hull so it's light.
 

Chef Treff

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So my guy only has a V-6 outdrive...pretty sure that would be 1.65/1 ratio and the 3.0 has 1.98/1....is that too much of a gap to make up with prop pitch?
Dunno if it matters but the boat is a 65 Starcraft aluminum hull so it pretty light.
Thanks
 

Scott06

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So my guy only has some V6 outdrives which I think are 1.65/1 but my current outdrive is 1.98/1 I think. Is that too much to make up with prop pitch?
The boat is a 65 Starcraft aluminum hull so it's light.
A V6 drive should be 1.81-1.84 depending on year … on step in drive ratio is 2” prop pitch change. I repowered a V6 boat with a 5.0, kept the 1.81 drive and stepped up from 19” to 21” pitch
 

Chef Treff

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Oh yea...got my drives mixed up there...lol
Anyway..so I could probably make that work it sounds like
 

Jamespio

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aCan't help you with your new drive, but I have one of the IC/IB/IC EX-shift drives. With the Chevy 230, 6 cyl.

Also fighting the tilt system, among other things.
 
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