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  1. #1

    Default Help identify my actual gearing

    Hi guys, I never post here but at this time I'm seeking for some help identifying my actual gearing. I have a carolina classic 25 with a 8.1 engine with a volvo penta dp d1 stern drive with b4 props and I'm only turning up to 4200 rpms when trimmed and about 3900 when is not trimmed and I'm supposed to be turning 4600 rpms, the serial number tag show that is a 1.78 gearing, I also remove the anode behind the propellers and I also see 1.78 but there is some engraved numbers in the propeller shafts and I've been told that by reading those number I actually have a 1.68 gearing. I would like to know if you can help me with this, the numbers in the propeller shafts are as follow:
    3855602 04-021
    044
    F-12 (R-3) P-3

    It looks like if I do have in fact 1.78 I should have a c4 props and that is why I'm trying to find out what my gearing really is as it looks like the gearing could have been changed and everything else, like the tag and housing left as stock.

    I would attach pics but so some reason it won't work.



    Thanks in advance for any help.
    Last edited by wellcraft26; 07-28-2017 at 01:28 AM. Reason: Notifcation

  2. #2
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,091

    Default Re: Help identify my actual gearing

    .............................
    Quote Originally Posted by wellcraft26 View Post
    ................... I have a carolina classic 25 with a 8.1 engine with a volvo penta dp d1 stern drive with b4 props and I'm only turning up to 4200 rpm when trimmed and about 3900 when is not trimmed and I'm supposed to be turning 4600 rpm.
    OK..... please note that the OEM specified WOT RPM is a "test" rpm only. It is NOT a cruise rpm nor an rpm to be sustained for any longer than testing ONLY. An engine that is in full tune and is healthy, should make WOT RPM.
    If it does not, it will be over-burdened.


    the serial number tag show that is a 1.78 gearing, I also remove the anode behind the propellers and I also see 1.78
    Unless the gear set has been replaced, and unless the technician failed to re-mark the bearing carrier, it is most likely the 1.78:1 over-all reduction.
    However, there is also a 1.68:1 reduction for this drive.
    This gear set's p/n is 3855602.
    (source = https://www.marinepartseurope.com/en...-44-10821.aspx )


    but there is some engraved numbers in the propeller shafts and I've been told that by reading those number I actually have a 1.68 gearing. I would like to know if you can help me with this, the numbers in the propeller shafts are as follow:

    3855602 04-021
    044
    F-12 (R-3) P-3

    It looks like if I do have in fact 1.78 I should have a C-4 props and that is why I'm trying to find out what my gearing really is as it looks like the gearing could have been changed and everything else, like the tag and housing left as stock.
    Please note that C-4 props would be SS.
    An impact with C series props is a recipe for bent prop $haft$.


    I would suggest that you verify your engine's health, state of tune, look at the hull bottom for marine growth, etc, and then re-visit your WOT RPM testing.
    Prop down if need be.

    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  3. #3

    Default Re: Help identify my actual gearing

    Thank you for replying, really appreciate it. The bottom is clean and as of right now it's getting a full tune up including the whole cooling system. I'm concern since I've been told about having a different gearing and but the forum members if I do have 1.78 I should have a different set of props as that's what they are all using. I'm mistaken about the prop in ss, I meant to say the next size prop but aluminum version , I'm not a fan of ss for the same reason u mentioned. I forgot which one they said
    I'm have always been an Outboard guys so I'm not really familiar with this stern drive.

    As soon as the boat get the tune up done it will go for a test again to see what happens, but I do want to find out what those numbers in the prop shaft means.

    Thanks again

  4. #4
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,091

    Default Re: Help identify my actual gearing

    When you have the tune-up done, ask that they verify the Progressive advance and the Total advance as per RPM.
    Reason: most mechanics will not look past their nose, and will set BASE advance ONLY!
    The engine will NOT perform to it's full potential unless the Progressive and Total are correct!

    As for the WOT RPM......... the gear reduction is close in either case. What you will do, is to re-prop until your WOT RPM is correct as per OEM specs.

    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  5. #5

    Default Re: Help identify my actual gearing

    Quote Originally Posted by RicardoMarine View Post
    When you have the tune-up done, ask that they verify the Progressive advance and the Total advance as per RPM.
    Reason: most mechanics will not look past their nose, and will set BASE advance ONLY!
    The engine will NOT perform to it's full potential unless the Progressive and Total are correct!

    As for the WOT RPM......... the gear reduction is close in either case. What you will do, is to re-prop until your WOT RPM is correct as per OEM specs.

    .
    Hi Ricardo, I was looking at this site and it looks like I do have 1.68 gears in my lower unit and was wondering if I a diy'er would be able to tackle this so I can replace it with the correct gears I need . Everyone in the forum with the 8.1 have 1.78 or 1.95. This is the link part number 25 https://www.marinepartseurope.com/en...-44-10821.aspx

    Thanks in advance.

  6. #6
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,091

    Default Re: Help identify my actual gearing

    .............................
    Quote Originally Posted by wellcraft26 View Post
    Hi Ricardo, I was looking at this site and it looks like I do have 1.68 gears in my lower unit
    Again..... 1.68:1 will be the final or over-all reduction.


    and was wondering if I a diy'er would be able to tackle this so I can replace it with the correct gears I need .
    You would need to have extensive hypoid gear work experience.
    The gear set alone will cost you approx $1,900.
    You'll want to also add the cost of all new bearings.


    Everyone in the forum with the 8.1 have 1.78 or 1.95.
    Not so!
    The 1.95:1 gear set is not strong enough for the 8.1L engine.



    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  7. #7

    Default Re: Help identify my actual gearing

    Good morning Ricardo, I'm replacing the seals in my LU dp d1 as its leaking a bit and was wondering if this is the correct seal kit (GLM87770) for it http://bpi.ebasicpower.com/shop/inde...oducts_id=7390 if not, do you have the correct kit?

    Thanks in advance

  8. #8
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
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    9,091

    Default Re: Help identify my actual gearing

    This is one area whereby I DO NOT use A-market parts..... either in Sierra or in GLM or in Mallory or ????
    It's just not worth using anything other than OEM parts for this.

    The job is actually very easy. However.... you are going to need a copy of my Prop Shaft Bearing Carrier puller tool.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Prop shaft carrier puller tool 1.jpg 
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ID:	16205  
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  9. #9

    Default Re: Help identify my actual gearing

    Thnks, I just built that tool and it worked great. I like using oem parts too as I like to do the work once and the best parts available, I already got the oem bellow and I need to get the seal kit for it. Do you know whee I can get it and the part number. Would like to order the kit today if possible.

    Thanks for replying.

    JR.

  10. #10

    Default Re: Help identify my actual gearing

    That's the only thing I have been able to find as a seal kit, but if I can get oem parts I would buy the oem. If thee isn't a kit, what should I replace then?

  11. #11

    Default Re: Help identify my actual gearing

    Think I found the correct part number for the oem, if this is the one I'm buying it 876267

  12. #12

    Default Re: Help identify my actual gearing

    I ordered the volvo oem LU seal kit that includes the upper too, how difficult is to replace the seals, is that something a diy'r could do or do I need special tools? Would like to know as I will have to cancel the order and just get the seal kit for the LU only.

    Thanks.

  13. #13
    Join Date
    Mar 2009
    Location
    Portland, Oregon,
    Posts
    9,091

    Default Re: Help identify my actual gearing

    Quote Originally Posted by wellcraft26 View Post
    I ordered the volvo oem LU seal kit that includes the upper too, how difficult is to replace the seals, is that something a diy'r could do or do I need special tools? Would like to know as I will have to cancel the order and just get the seal kit for the LU only.

    Thanks.
    I do not think of a DIY'r as being trained person who has enough experience to perform a task with expertise.
    However, some skills transfer over very nicely, and the task is completed with confidence.

    When it comes to working on an item that is both technical AND expensive (such as your Volvo Penta stern drive), I would suggest that you use extreme caution.




    .
    Rick ... aka Ricardo..... AQ series Volvo Penta repair
    Portland, Oregon
    28' SDN F/B w/ twin Volvo Penta 5.7L DP's

    Please... no PMs! Post your questions on the forum.

  14. #14

    Default Re: Help identify my actual gearing

    I was just looking at the kit I ordered and I realized is just the LU seal kit, trying to find the upper seal kit to do the whole thing. I consider my self really good when it comes to wrenching, there are a lot of things that I needed guidance but thankfully have done a great jod at the end. I know a Johnson outboard engine is different but I took apart the LU once using a service manual and it's been working great for the past 8 years.

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