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  1. #1

    Default Old School Merc Parts?

    I have an old (1966) Mercury 350, the entire thing has been gone through, including new pistons, rings, heads, etc. Sadly, with the new power the forward gear and dog have just started slipping. I have done search after search and can't seem to find the parts needed.

    Does anyone have a special place, or even know of a place to get new gears?

  2. #2
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    Default Re: Old School Merc Parts?

    Try Tim's Outboard in Hackensack MN, 218 682 2331, Mike or Dan, girls to answer phone are Calley or Theresa.

  3. #3
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    Default Re: Old School Merc Parts?

    I doubt that the gears are slipping.-------Perhaps the hub in the prop is slipping.-----What is your motor doing / not doing ?----Your location?

  4. #4

    Default Re: Old School Merc Parts?

    Thank you timguy! Racerone, when I'm on the water it was fine until the RPMs got about 3k, then in pops out of gear and revs up. Popped out 4 more times attempting to get back to my trailer. Had to cruise back to the dock at about 8knots to keep it from popping out. I'm in the California Bay Area. I can swap out the prop and try again. I don't want to deal with marking the prop and checking for spin since I have no interest in getting stuck out on the water and paddling back
    Last edited by 73Futura; 01-15-2022 at 10:08 AM.

  5. #5
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    Default Re: Old School Merc Parts?

    First thing I would do is try another prop !!----Or mark the hub and outer portion of your prop.----Test run and see if marks have moved.-----Some will argue , but I say you need another prop.

  6. #6
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    Default Re: Old School Merc Parts?

    It's the prop hub slipping!

    Jeff

  7. #7

    Default Re: Old School Merc Parts?

    How much did they charge to do the heads? Is the shift cable set up properly, shift into Neutral, make sure the prop spins freely then remove the cable and see if it's under tension. It should move out of the anchor easily if not turn the brass barrel until it slides in.
    Did you work on the lower unit?
    Last edited by Quicksilver; 01-15-2022 at 05:01 PM.

  8. #8
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    Default Re: Old School Merc Parts?

    Ok-----So what motor is this ?----A 66 Mercury 350 outboard or a Mercruiser 350 Chevy Sterndrive.------Model # is ?

  9. #9
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    Default Re: Old School Merc Parts?

    Popping out of gear is not prop related. Otherwise your response would suggest the hub in the prop is damaged.

    I'd say you have a linkage alignment problem, a worn out clutch dog spring, or the front of the clutch dog and rear of F gear are worn to the point that the sawtoothed gearing has its corners rounded off and will not hold the pressure of the higher rpms torque. But I'm not a professional mechanic. Just a guy whose been there.

  10. #10
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    Default Re: Old School Merc Parts?

    We need more info. I don't believe that a mid 60s Merc 35 hp outboard has a head. I could be wrong, I also don't believe it can be a 1966 350 GM because Chevy did not make one until 1967.

  11. #11

    Default Re: Old School Merc Parts?

    Merc's back then didn't have "heads" they came in with the V6's in 1975.
    The gears are very tough I have a set from the 70's that show very little wear including the clutch so, I'm leaning towards prop or cable problems.

  12. #12
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    Default Re: Old School Merc Parts?

    On tough gears, I restored a 110 HP 1965 Mercruiser and what I said was the case. I couldn't find the gears so I went to a machine shop to see if they could help me. Answer is no way.....too hard!

  13. #13
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    Default Re: Old School Merc Parts?

    I had em cut all the time when my machinist was alive....$50 for forward and dog. Even had a few users of this forum contact him and repair gears. That machine shop fed you some BS that gears are too hard.
    Charlie Southgate - The Music City MacGyver | News | nashvillescene.com
    Pappys Sales and Service
    Owner and Factory Certified Technician
    Former racer KDBA (Kentucky Drag Boat Association)

  14. #14
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    Default Re: Old School Merc Parts?

    Technology has changed.----Shops used to grind hardened material to close tolerances.----A slow process.----They now " turn " to finished sizes using diamond cutting tools.----All done to speed things up and cut production costs.

  15. #15
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    Default Re: Old School Merc Parts?

    Then why is everything so expensive? Dad bought a BRAND NEW 1970 Ford Maverick with a 250 six and C4 automatic for $2,200. I outran the cops once with it. Wonderful car and pretty fast. 25 to 30 mpg on regular fuel. Gas was 33 cents a gallon. So where are we REALLY going? How are we gonna build/dispose of all the electric vehicle batteries?
    That's a whole nother story. If you have the nerve, read this....right from AAA.
    https://magazine.northeast.aaa.com/d...e-environment/

    Now, if you can't find lower unit parts, I might let go of my 66 Merc 350 parts. I do have a prop too, however, props are certainly quite available.
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  16. #16
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    Default Re: Old School Merc Parts?

    Waiting for up-date from Futura in a few days.-----He stated --" jumping out of gear "-----But likely it is just revving up due to prop issues.-----If it was the clutch dog grinding the there would be lots of noise and boat would come to a ---" dynamic halt "

  17. #17
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    Default Re: Old School Merc Parts?

    Charlie used a J head Bridgeport and cutter to fix gears and dogs. ..secret was to remove the same amount off each ramp and 5 offset. Same for dogs..
    Pappys Sales and Service
    Owner and Factory Certified Technician
    Former racer KDBA (Kentucky Drag Boat Association)

  18. #18
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    Default Re: Old School Merc Parts?

    5 off set? Interesting! What are they from the factory? Square, eh?

  19. #19
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    Default Re: Old School Merc Parts?

    Quote Originally Posted by faztbullet View Post
    I had em cut all the time when my machinist was alive....$50 for forward and dog. Even had a few users of this forum contact him and repair gears. That machine shop fed you some BS that gears are too hard.
    Charlie Southgate - The Music City MacGyver | News | nashvillescene.com
    Maybe they didn't know how to soften, cut, and reharden or just didn't want to fool with it.

  20. #20
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    Default Re: Old School Merc Parts?

    Quote Originally Posted by racerone View Post
    Waiting for up-date from Futura in a few days.-----He stated --" jumping out of gear "-----But likely it is just revving up due to prop issues.-----If it was the clutch dog grinding the there would be lots of noise and boat would come to a ---" dynamic halt "
    Well it wouldn't take a NY minute to mark and test the prop to eliminate that question!

  21. #21

    Default Re: Old School Merc Parts?

    Thank you all for your help. I got super excited with the thought of a slipping bushing, but sadly, it's still a work in progress. I finally got some time to test another prop over the weekend. Still popping out. It is a 1966 mercury 350, 35hp outboard. The entire engine has been rebuilt, but for lower end only the water pump and impeller were changed. The prop I tested was brand new, purchased from a shop who said "too old, we don't touch em" when asked about gears. Got the cheapest one possible since it was just a test, feel like it was worth the $128 to test before tearing apart the lower unit. I did watch a video on youtube where a guy ground them down. Think that's my plan since the gears seem to be impossible to find.

    The worst part is, I tried to buy a brand new outboard. I had $7k set aside for this boat rebuild, and used only about $600 for the entire interior remodel and exterior upgrades since I already had several dozen yards of vinyl and about 8 gallons of top coat from a 46' carver remodel that I never started. I contacted several stores and they all said they either didn't have any 30-40hp outboards, or they would only sell it to me if they installed it, at a roughly estimated $3k extra. I'm sorry, but I have a degree in automotive engineering, have designed and built vehicles that were shown at SEMA, and have built some of the fasted cars and motorcycles on the planet, there's no way I'm going to pay someone $3000 to run a couple cables and a power line. So....in comes this old trouble maker.

  22. #22
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    Default Re: Old School Merc Parts?

    Did it shift / stay in gear before the water pump work ?-----Drain gear oil.----Examine oil for metal bits.-----This should be an easy diagnosis.----Not sure why you did not mark the prop ??----There really should not be an issue finding gears.------Visit -----aomci-----And post a wanted ad there.

  23. #23
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    Default Re: Old School Merc Parts?

    Very interesting. Is this a short or longshaft? You mean that to buy a new motor.....you must let them install it, or the warranty is void? That's insane. Would love to see a dealer that could install a motor as properly as one of us, eh?
    If you'd consider a Tohatsu, the Hibbing MN dealer will sell you one at just over cost....cash and carry. He will cover your installation, as he would have done it himself, if you can convince him of your ability. Warranty will be honored.
    Last edited by timguy; 01-18-2022 at 11:42 AM. Reason: Add info

  24. #24

    Default Re: Old School Merc Parts?

    Quote Originally Posted by racerone View Post
    Did it shift / stay in gear before the water pump work ?-----Drain gear oil.----Examine oil for metal bits.-----This should be an easy diagnosis.----Not sure why you did not mark the prop ??----There really should not be an issue finding gears.------Visit -----aomci-----And post a wanted ad there.
    I DID mark the prop, the hub didn't spin. I figured I'd try every avenue and leave no stone unturned and try a new prop, just in case. Statistically speaking, the odds of it spinning an exact 360 are slim, but I wanted a 4 blade prop for those days when I invited extra people anyway since I only had the 2 blade prop. It ran, but weak, topping out at about 12mph is what I was told by the previous owner. My guess is it was slipping then also, he just didn't know what it was. I'm going to take it apart next weekend and take a look. At this point I'm just disappointed that the lower unit wasn't rebuilt with the engine, and think I'd rather rebuild it regardless of condition. Which takes me back to my original post of finding the new gears. You'd think it would be easy to find, but sadly, I can find a WHOLE MESS of gears for all the 70s+ outboards but the 60s seem to be a black hole for parts. And I can't seem to find a cross reference guide either, it would be awesome to fine SOMETHING.

    Quote Originally Posted by timguy View Post
    Very interesting. Is this a short or longshaft? You mean that to buy a new motor.....you must let them install it, or the warranty is void? That's insane. Would love to see a dealer that could install a motor as properly as one of us, eh?
    Quote Originally Posted by timguy View Post
    If you'd consider a Tohatsu, the Hibbing MN dealer will sell you one at just over cost....cash and carry. He will cover your installation, as he would have done it himself, if you can convince him of your ability. Warranty will be honored.
    It's longshaft. I went to buy a brand new complete outboard but they said they can't sell it to me without installation due to warranty issues. If they said something like $500, I'd say "what ever" and let them do it for the warranty sake, but not $3k-$3,500, that's absurd! It has nothing to do with me thinking it wouldn't be installed properly, it's more me being far too intelligent to overpay for labor. I'm old, I do pretty much everything myself, I know that $3k is FAR too much for such a simple task. But then again, I also don't pay someone $120 to come change a flat tire like a lot of other people do. As far as Tohatsu goes, I love Tohatsu, and have had a couple, but they also required installation. I think with the outboard shortage shops are just milking it for what they can get.
    Last edited by 73Futura; 01-18-2022 at 01:56 PM. Reason: reply to timguy

  25. #25

    Default Re: Old School Merc Parts?

    Is your 350 a long shaft using a Bay Manufacturing extension housing with a driveshaft stub extension? What is your serial number?

  26. #26
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    Default Re: Old School Merc Parts?

    Have we positively determined that it is popping out of gear? Do you have to re-enter forward by applying the control lever back to forward? Is there a "jolt" when it "looses" gear? Does it "reboot"....so you speak, for lack of a better term....by just backing off the throttle and bringing speed back up slowly? There is quite a massive difference of symptoms when we are experiencing either a slipping hub or a bad transmission. Of course it's not like an old GM Powerglide, eh?
    I have a beautiful 350 tiller SS. Might consider sending you the lower unit. Seems folks don't care much for the old big twins, right? Me, I have always preferred the 4 bangers, (Mark 30), like in my photo avatar. These were rocket ships. Here 3 big boys in a 16' Cadillac with 6 Evinrude, cooler with ice, fishing gear for a day, 20 pounds worth of deep sea sinkers, and 18 gallons fuel. Still here, but temporarily retired. Could run right with Dad's 40 hp Lark on a 16' Alumacraft Yukon. Now THATS a sweet Merc.
    Last edited by timguy; 01-18-2022 at 04:04 PM. Reason: Add info

  27. #27
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    Default Re: Old School Merc Parts?

    And you are sure that it is not an ignition issue.-----Possible losing spark on one cylinder ?------
    Last edited by racerone; 01-18-2022 at 04:51 PM.

  28. #28

    Default Re: Old School Merc Parts?

    There are a few possibilities: 1:The shift cable is not set up correctly. 2:The lower shift shaft is not in the correct rotational position. 3:The bearing carrier nut is backing out decreasing pressure on the shift dog.
    There is only about 1/4" of contact on the clutch dog + F gear and if it's not being pressed in solidly it will slip but, this would occur at all rpms, it would sit and spin. The design is spring loaded so that when it's in forward it stays in forward.

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  29. #29
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    Default Re: Old School Merc Parts?

    Have you ever seen the spring get rusty? I have too, then there is not enough pressure to hold detent into position. In order to make progress with this thread, we need some questions answered, eh? We are all simply speculating. If the motor was in our hands we would know exactly what to do. Our questions are directed to form an accurate diagnosis....no answers, no diagnosis. If this transmission has seen water infiltration, then stored, we may have a problem. Please, answers to my post #26. Banana bread is almost done, then I go out and shovel this mess of snow. Will check back in later.
    Last edited by timguy; 01-19-2022 at 02:29 PM. Reason: Add info

  30. #30

    Default Re: Old School Merc Parts?

    I took the easy route, took it to a buddy who just swapped out the lower unit. Took it out and it's running great with my original prop, pretty exciting to be back on the water. Thank you for all your help.

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