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Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

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  • Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

    I was hoping the Mercruiser gods (Bondo and team) could answer a question regarding alpha 1 gen 2 conversion to alpha 1 gen 1. Here is the background;

    I have two boats; The old boat which is a 1990 Larson 19' the original 4.3 Mercruiser and Alpha 1 Gen 1 outdrive.
    The new boat is a 1995 Rinker 180 18' with a 3.0 Alpha 1 gen 2 outdrive.

    Here is what I want to do; Take the 3.0L engine gimbal housing and Alpha 1 Gen 2 drive out of the Rinker and sell it. Take out the 4.3L engine, gimbal housing and Alpha 1 Gen 1 out of the 1990 Larson and install it in the 1995 Rinker. I know, I know, before everyone says it a lot of work and that I have to make motor mounts I am aware of all that and have experience with fiberglass work plus I have the 1990 Larson I can take measurements off of and cut the existing motor mounts out and use them as a template so that is a non issue.

    The reason for doing the swap is the 1990 Larson is shot (left out in the elements its entire life) but the running gear is in great shape mechanically (always service by local dealer and have all the receipts). The 1995 Rinker is in excellent shape but the 3.0L is under-powered for the size of the boat.

    I know, I know... Just sell them both and buy a boat with a bigger engine. I would do that but in Minnesota used 17' to 19' boats go for the price of gold and hard to find for a reasonable price. No, I will not buy a Bayliner regardless. I own both boats already and have very little invested in either (total of $4K).

    The Rinker is a beautiful boat, well made, very good finish and in showroom condition. Some general questions for all of you;

    1) With the Alpha 1 Gen 1 fit in a Alpha 1 Gen 2 transom hole with bolt patterns lining up?
    2) Will the Mercruiser wiring harness unplug from the 3.0 and plug directly into the 4.3?
    3) Other than modifying the shift cable and throttle to work,what else would I have to worry about?

    Thanks for all of your help. I can be talked out of it but I have the time to explore my options. any other comments are welcome.

    Thanks,
    Steven

  • #2
    Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

    #1) yes. (you might end up with 2 holes at the top of the cut-out that the 'Gen 1' doesn't use, but they are no problem.
    #2) yes. Should be just plug and pray (You will need to change the setting on the back of the tacho from the 4 cyl to the 6 cyl).
    #3) Just make sure the exhaust y-pipe has clearance.

    Chris....
    (not sure if I'm in the Bondo/god category )
    xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
    The world takes on a whole new perspective when viewed from 100’ below.
    1972 Bertram ‘Bahia Mar’ 20
    2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
    (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


    Comment


    • #3
      Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

      Originally posted by sweninge View Post
      3) what else would I have to worry about?
      There is a chance that your 3.0 did not have an audio warning horn system installed while the 4.3 did. You may have to find the warning horn under the dash and install it in the newer boat.

      Oh and I'm not sure if Chris is saying to plug in and pray everything works or plug in and play..... just kidding.

      Keep track of where the trim limit and gauge "sending unit" wires hook up to between the two engines as I believe the 1990 may be connected in a different spot vs the 95. Easy to lose track of that sometimes.

      As a precautionary measure, I would install everything before you sell everything.

      Good luck.
      OEM Quality Gear Lubes And Greases Available @ iboats.com 'By Bel-Ray Marine Lubricants -- BOAT SPECS -- FORUM GUIDELINES -- Volvo, OMC & Merc Stern Drive Technical Information For DIYers. -- OEM VOLVO PARTS POWERED BY iBOATS.COM -- All OEM Parts / Parts Lookup Now Available Through iboats.com --

      Comment


      • #4
        Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

        Originally posted by achris View Post
        #1) yes. (you might end up with 2 holes at the top of the cut-out that the 'Gen 1' doesn't use, but they are no problem.
        #2) yes. Should be just plug and pray (You will need to change the setting on the back of the tacho from the 4 cyl to the 6 cyl).
        #3) Just make sure the exhaust y-pipe has clearance.

        Chris....
        (not sure if I'm in the Bondo/god category )
        Thanks Chris. I have learned a ton of information on this forum and I appreciate you knowledge. Thanks again for taking the time. I decided to include Bondo in my post because he seems to give straight forward advice and that is what I need. Everything you said makes perfect sense.

        Comment


        • #5
          Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

          Originally posted by Fun Times View Post
          There is a chance that your 3.0 did not have an audio warning horn system installed while the 4.3 did. You may have to find the warning horn under the dash and install it in the newer boat.

          Oh and I'm not sure if Chris is saying to plug in and pray everything works or plug in and play..... just kidding.

          Keep track of where the trim limit and gauge "sending unit" wires hook up to between the two engines as I believe the 1990 may be connected in a different spot vs the 95. Easy to lose track of that sometimes.

          As a precautionary measure, I would install everything before you sell everything.

          Good luck.
          There will be praying and some swearing I am sure before this is done. This project is still in the debate stage but I know the Rinker is very well made boat and want to keep it for the long haul. In order to do that I need more power... Plus a 4bl carb on the 4.3 is a nice easy upgrade down the road. The 3.0 is a bullet proof motor but there is not much you can do to it performance wise. Plus I think they weigh between the two engines is almost the same so the boat should handle it ok.

          Thanks again.

          Comment


          • #6
            Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

            I read what you wrote. And maybe I am misunderstand you. But why don't you just take the 4.3 and install it into the boat that you want, and be done with it. And then on your gearing, either regear the upper or get an SEI geared for the 4.3. And then sell your leftovers?

            Why are you swapping the transom assemblies over? Seems like a lot of work. Or am I missing something here?
            just because you found it that way does not mean it is supposed to be that way.

            Comment


            • #7
              Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

              Originally posted by sweninge View Post
              There will be praying and some swearing I am sure before this is done. This project is still in the debate stage but I know the Rinker is very well made boat and want to keep it for the long haul. In order to do that I need more power... Plus a 4bl carb on the 4.3 is a nice easy upgrade down the road. The 3.0 is a bullet proof motor but there is not much you can do to it performance wise. Plus I think they weigh between the two engines is almost the same so the boat should handle it ok.

              Thanks again.
              Ayuh,.... Welcome Aboard,.... The 4.3l will be 'bout 100 lbs or so heavier,....

              Yer plan is Doable, so long as ya swap everything Merc bolted into the boat, for Everything outa the other boat,....

              Wirin' should swap Ok, cables may, or may not be long enough,....

              How 'bout the motor box width,..?? I think ya need 32" inside for the V-motor,...

              Mercruiser gods is pretty steep,..... Don is now among 'em,...
              I'm just a backyard Mechanic,... King of Cob maybe,...

              Comment


              • #8
                Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                Originally posted by JustJason View Post
                I read what you wrote. And maybe I am misunderstand you. But why don't you just take the 4.3 and install it into the boat that you want, and be done with it. And then on your gearing, either regear the upper or get an SEI geared for the 4.3. And then sell your leftovers?

                Why are you swapping the transom assemblies over? Seems like a lot of work. Or am I missing something here?
                I thought the gen 2 outdrive and gimbal house was different from the gen 1 Alpha as far as the drive shaft lengths, rear mounting, y-pipe and gimbal bearing size? If this is not true someone please confirm... I know the gear ratio in the upper housing would need to change for the 4.3L compared to the 3.0L. I know the Alpha gen 2 would be a better drive then a gen 1 and I would love to do what you are recommending but then I am buying an upper housing and new drive shaft to work with my Alpha gen 1 engine setup. Maybe I am looking at this wrong and can same some work.

                Comment


                • #9
                  Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                  Originally posted by Bondo View Post
                  Ayuh,.... Welcome Aboard,.... The 4.3l will be 'bout 100 lbs or so heavier,....

                  Yer plan is Doable, so long as ya swap everything Merc bolted into the boat, for Everything outa the other boat,....

                  Wirin' should swap Ok, cables may, or may not be long enough,....

                  How 'bout the motor box width,..?? I think ya need 32" inside for the V-motor,...

                  Mercruiser gods is pretty steep,..... Don is now among 'em,...
                  I'm just a backyard Mechanic,... King of Cob maybe,...
                  Thanks Bondo. I knew you would respond. I have more then 32" width and have plenty of room for the Y-pipes as I already measured. Reading your post basically confirms what I was originally thinking. I have to take everything off the donor boat (1990 Larson 4.3L V6 Alpha 1 Gen 1) out from the prop to the front of the motor including the gimbal housing. If I want to keep the Alpha 1 Gen 2 drive and gimbal housing (1995 Rinker Currently 3.0L Gen 2) I need to buy a new upper housing with the correct gearing and y-pipe setup for the Gen 2 and a driveshaft the correct length and size to match the different gimbal bearing size plus the bellows are different sizes/type as well. What do you recommend (other than buying a boat with a bigger engine)?

                  Comment


                  • #10
                    Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                    Originally posted by sweninge View Post
                    I thought the gen 2 outdrive and gimbal house was different from the gen 1 Alpha as far as the drive shaft lengths, rear mounting, y-pipe and gimbal bearing size? If this is not true someone please confirm... ....
                    The yoke lengths only varied on the MC-1 drives (pre-1982). And it was only the inline engines that were different. Since 1982 all the yokes are the same, V engine, in-lines, 'gen 1' and Gen II..... The gimbal bearing has been the same since about 1971 until current.

                    Originally posted by sweninge View Post
                    ... confirms what I was originally thinking. I have to take everything off the donor boat (1990 Larson 4.3L V6 Alpha 1 Gen 1) out from the prop to the front of the motor including the gimbal housing. If I want to keep the Alpha 1 Gen 2 drive and gimbal housing (1995 Rinker Currently 3.0L Gen 2) I need to buy a new upper housing with the correct gearing and y-pipe setup for the Gen 2 and a driveshaft the correct length and size to match the different gimbal bearing size plus the bellows are different sizes/type as well. What do you recommend (other than buying a boat with a bigger engine)?
                    Your old V-6 engine y-pipe will bolt straight onto the Gen II gimbal housing. All you would need is a new upper housing with the right ratio. The drive shaft lengths, the gimbal bearing and all that stuff is the same. You could easily just pull the 3.0 litre out (and its exhaust pipe), bolt up the V6 y-pipe and drop the V6 straight in, even the instrument harness will plug straight in. As for selecting a ratio, the Rinker is a small(ish) boat for the 4.3, so I would go to the 1.62:1 ratio. http://www.boatmotors.com/motorparts...id=7526&flag=2 What you may not be able to set up is the drive oil monitor bottle. For that you would need the fitting in the front of the drive and all the hardware inside the boat. Personally, I wouldn't bother, drives had been running for years without them, and as long as you do your oil changes each year, you shouldn't have any problems.

                    HTH,

                    Chris.....
                    Last edited by achris; March 2nd, 2014, 08:06 PM.
                    xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                    The world takes on a whole new perspective when viewed from 100’ below.
                    1972 Bertram ‘Bahia Mar’ 20
                    2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
                    (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


                    Comment


                    • #11
                      Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                      Originally posted by achris View Post
                      The yoke lengths only varied on the MC-1 drives (pre-1982). And it was only the inline engines that were different. Since 1982 all the yokes are the same, V engine, in-lines, 'gen 1' and Gen II..... The gimbal bearing has been the same since about 1971 until current.

                      Well I learn something everyday. Valuable information, thanks Chris.


                      Your old V-6 engine y-pipe will bolt straight onto the Gen II gimbal housing. All you would need is a new upper housing with the right ratio. The drive shaft lengths, the gimbal bearing and all that stuff is the same. You could easily just pull the 3.0 litre out (and its exhaust pipe), bolt up the V6 y-pipe and drop the V6 straight in, even the instrument harness will plug straight in. As for selecting a ratio, the Rinker is a small(ish) boat for the 4.3, so I would go to the 1.62:1 ratio. 1990 Mercruiser Stern Drive Upper Drive Assembly - 1.62 gear ratio - New Aftermarket - iboats.com What you may not be able to set up is the drive oil monitor bottle. For that you would need the fitting in the front of the drive and all the hardware inside the boat. Personally, I wouldn't bother, drives had been running for years without them, and as long as you do your oil changes each year, you shouldn't have any problems.

                      HTH,

                      Chris.....
                      That would save me a lot of time and I would end up with a better system. Thanks again Chris. I think I would be miles ahead spending the extra money to buy the Gen 2 upper and not messing with pulling the Gen 1 gimbal housing off the donor boat. The Rinker is 18' and at 4,500 RPM's WOT it runs about 40MPH on GPS. I would like to get closer to 45MPH+ so you thing 1.62:1 ratio is the best way to go?

                      Now if I could just do something about the hot pink trim on the seats that came from the factory I would really have the boat I wanted. Wife likes the color but I will never understand what they were thinking in the mid 90's when it came to interior color.

                      Thanks again ~Steven

                      Comment


                      • #12
                        Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                        Originally posted by sweninge View Post
                        That would save me a lot of time and I would end up with a better system. Thanks again Chris. I think I would be miles ahead spending the extra money to buy the Gen 2 upper and not messing with pulling the Gen 1 gimbal housing off the donor boat. The Rinker is 18' and at 4,500 RPM's WOT it runs about 40MPH on GPS. I would like to get closer to 45MPH+ so you thing 1.62:1 ratio is the best way to go?

                        Now if I could just do something about the hot pink trim on the seats that came from the factory I would really have the boat I wanted. Wife likes the color but I will never understand what they were thinking in the mid 90's when it came to interior color.

                        Thanks again ~Steven
                        Ayuh,.... Then I wouldn't be changin' it,....

                        Comment


                        • #13
                          Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                          Originally posted by Bondo View Post
                          Ayuh,.... Then I wouldn't be changin' it,....
                          She won't know until after it's done. Best option I have found over the years is just nod my head and do what I was planning to do anyway.

                          If her shoes don't match the purse she buys a new one. I can do the same with my boat seats. Vinyl dye seems to work OK for a while anyway.

                          Comment


                          • #14
                            Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                            Originally posted by sweninge View Post
                            That would save me a lot of time and I would end up with a better system. Thanks again Chris. I think I would be miles ahead spending the extra money to buy the Gen 2 upper and not messing with pulling the Gen 1 gimbal housing off the donor boat. The Rinker is 18' and at 4,500 RPM's WOT it runs about 40MPH on GPS. I would like to get closer to 45MPH+ so you thing 1.62:1 ratio is the best way to go?
                            My boat is a HEAVY 20 footer, and my 4.3 runs a 1.62:1 drive and I still need a 19" prop. With that prop I'm at 43 knots (50mph), so yes, I think that drive on your boat would probably run a 21" or even a 23" prop. You might be looking at a 55 or 60 mph boat.

                            Now if I could just do something about the hot pink trim on the seats that came from the factory I would really have the boat I wanted. Wife likes the colour but I will never understand what they were thinking in the mid 90's when it came to interior color.

                            Thanks again ~Steven
                            Happy wife, happy life. Leave the seats pink!
                            xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                            The world takes on a whole new perspective when viewed from 100’ below.
                            1972 Bertram ‘Bahia Mar’ 20
                            2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
                            (Original - 1972 '165' In-line 6. Previous - 1994 4.3LX)


                            Comment


                            • #15
                              Sign up today
                              Re: Alpha 1 Gen 2 conversion to Alpha 1 Gen 1 Running gear

                              Originally posted by achris View Post
                              My boat is a HEAVY 20 footer, and my 4.3 runs a 1.62:1 drive and I still need a 19" prop. With that prop I'm at 43 knots (50mph), so yes, I think that drive on your boat would probably run a 21" or even a 23" prop. You might be looking at a 55 or 60 mph boat.



                              Happy wife, happy life. Leave the seats pink!
                              ASSUME! I am sure to scare the H$%L out of anyone that dare ride this think when I am done. Going that fast with pink seats has got to get me some respect. Wife doesn't like to go over 30. She says it scares her. My 5yr old daughter and to sons 7 and 9 yell to go fast! Daughter likes the hot pink too.

                              Thanks Chris for the info on the prop pitch. Now I just need to wait until it's above -10 to work on it.

                              Thanks again everyone.

                              Comment

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