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OMC Tech Please Help... Which Rings for '62 Lark 40hp Outboard

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  • OMC Tech Please Help... Which Rings for '62 Lark 40hp Outboard

    Hi Gents,

    This is an outboard question.. I have had no luck at Evinrude/Johnson board and was hoping somoene over here could help.

    I am working on a 1962 Evinride Lark IV M#35530 40 hp.

    I have also posted on several boards as well as checking with a few of the suppliers I have ordered from and nothing! This is a good one for the OMC techs.

    On my 1962 I have been comparing to BRP parts catalogs for 1968 models because as you know they only go back to '68 and it seems like the rest of the world only goes back to 1968 too! I wonder what happened... it's not like any Evinrudes were made before 1968 or anything!! I bet that the day that BRP sat down to upload all the old OMC data they were just overwhelmed by the sheer amount of data and had to draw the line at 1968. Also from what I have seen, OMC was always making changes, especially in late 50's and early 60's so I am figuring (and hoping) that is what happened here. Would love to hear any old OMC stories... really hated to see them go out of biz to another company just because they happened to be the first ones standing there with the cash! Anyways would also love to hear why in the heck BRP only goes back to 1968 if anyone knows.

    I have an original parts manual for my 1962 (not a copy)... nearly EVERY part number is the same as the 1968 on BRP's parts catalogs so thus far it's been pretty easy.

    Except for these:

    My 1962 part numbers from my '62 evinrude parts manual:
    Rings #378430
    Pistons #378695
    Block #378647(cylinder & crankcase)
    OS Rings #378433
    OS Piston #378697
    Crankshaft #554326

    1968 part numbers:
    Rings #380108
    Pistons #383068
    Block #380253 (cylinder & crankcase)
    OS Rings #380109
    OS Piston #383069
    Crankshaft #311356

    Now, as I said nearly evey other number is the same.. all the way down to the last screw... except these! The oversize ring/piston numbers are also different as you see, as is the crankshaft.

    Did OMC just change the part numbers? I can find NO cross-reference on anything so I am thinking they were changed.

    You see, the issue is that I have two bad 1962 blocks (scored cylinder and no compression in one cylinder). So if anything I need to bore the bad cylinder and go oversized but same problem.

    I also have a line on a good '68 block so that would allow me to order the '68 rings but I want to use my '62 pistons and crankshaft (and I also need to mount the block on my existing lowerleg (exhaust housing) and wouldn't you know, those #'s are also different 1962: #377988... 1968: #379385).

    These items all appear visually identical of course.

    Will my 62 pistons and 62 crank fit the 68 block and...
    will the 68 rings fit my 62 pistons?

    I have been able to order tons of 1968 parts and they all marry my '62 perfectly... only these hard engine parts are giving me trouble.

    Any help GREATLY appreciated. I got this motor for $25 and thought I was getting a good deal but it's turned out for me replacing nearly everything!!

    ALSO: Now take a look at this... the Rod for the '62 is #378541 and the '68 rod is #378275, different numbers... BUT... the rod split bearings (#378528) are the SAME... AND... the center crank split bearing (#378838).. wow, light at the end of the tunnel! I bet they'll fit and I bet they changed the numbers, anyone know?

    Thanks a million All,

    Shawn T
    Wichita, KS

  • #2
    Re: OMC Tech Please Help... Which Rings for '62 Lark 40hp Outboard

    keep reposting in the J/E section.
    some of the early 40 motors had a 3 ring piston and the later a two ring and a different ring desighn.
    google keystone rings,semi keystone and square cut.
    OMC went out due to faulty QC due to a Mr soros that bought OMC outright,took it private and split it off then walked away with a large profit leaving a bankrupt company.
    its not profitable for BRP to make parts for something they dont and never did make thats dirt old.
    finding studebaker,edsal or nash metropolitan parts is about the same.
    no tech questions by PM, they wont get answered.
    you have to be trusted by the people that you lie to .


    • #3
      Re: OMC Tech Please Help... Which Rings for '62 Lark 40hp Outboard

      Doesn't sound surprising with Soros. Carl Icahn too.

      I had some more info on the part numbers. I have had good luck with Jack at Sea-Way and they had recommended I call BRP on this. I told him they probably wouldn't talk to me since mione was older than 1998 but I called anyway and they actually talked to me! The guy said they try to be flexible. He said they "didn't have the manpower" to put all the data in prior to 1968...

      He informed me that he was certain that the cubic inch displacement was different and although rod and crank bearings were the same, they would not interchange.


      The wrist pin is the same (#307148).. with that in mind I should be able to bore out the bad '62 cylinder and go oversized piston and oversize rings on that hole. One catch though, the original '62 OS piston (#378697) or OS rings (#378433) are not available anywhere! The 68' OS rings (#380109) are available but the OS Piston (#383069) is slim pickins (I seen a few and will hold out).. anyone have one?

      I also have a line on a 68 block but then I will have to find an adapter so it will fit on my lower leg according to the guy at BRP. Not to mention 2 new pistons and crank just to start.

      I may be able to find a good '62 block but standard rings (#378430) are NOWHERE.

      So what would be the best course of action?


      Shawn T


      • #4
        Sign up today
        Re: OMC Tech Please Help... Which Rings for '62 Lark 40hp Outboard

        This also brings me to another question going back to parts availability.

        What do you guys out there with 40 hp evinrude, johnsons or omc's from late 50's to mid 60's do for rings?!?!?

        Too bad, I bet there is a market for this stuff. Too bad not more aftermarket. I have done 3 orders from BRP picking through their '68 items for my '62 and I know Im not the only one! I see a lot of people with these motors.