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Thread: Outboard Rebuild

  1. #1

    Outboard Rebuild

    I am thinking of getting my 2 stroke outboard rebuilt rather than over capitalise on an old boat or take the risk of buying a second hand outboard. I am pretty sure you have to following the running in procedure at per if it was new (extra oil, limits on speed). But what about a 20 hr service? Does it need the cylinder head bolt tensions to be re-checked? Anything else?

  2. #2
    Ausfish Platinum Member
    Join Date
    Mar 2015
    Location
    Kalbarri, WA

    Re: Outboard Rebuild

    Just basic engine procedures, I would imagine. I can't see why there would be a 20 hour service--no oil to change. Just retorque the head after a while, Check the plugs for signs of lean running, look for leaks. Old two strokes are pretty simple, part of their attraction. Best to get a rebuild kit for the carbs, you don't want to wreck a newly rebuilt motor for the sake of that.

  3. #3

    Re: Outboard Rebuild

    Quote Originally Posted by ranmar850 View Post
    Just basic engine procedures, I would imagine. I can't see why there would be a 20 hour service--no oil to change. Just retorque the head after a while, Check the plugs for signs of lean running, look for leaks. Old two strokes are pretty simple, part of their attraction. Best to get a rebuild kit for the carbs, you don't want to wreck a newly rebuilt motor for the sake of that.
    Well wouldn't a re-torque of the head constitute a service? You wouldn't need to drop the gearbox oil as is done with a new motor but my thinking was that a lot of the service requirements would be the same at around 20 hrs.

  4. #4

    Re: Outboard Rebuild

    Why do you think it needs rebuilding? Any machine work needs to be done by someone who knows outboards, not just an auto machine shop.

  5. #5

    Re: Outboard Rebuild

    Quote Originally Posted by Noelm View Post
    Why do you think it needs rebuilding? Any machine work needs to be done by someone who knows outboards, not just an auto machine shop.
    I have taken it to a well established marine mechanic. They found low compression in one cylinder and found damage to the piston and bore.

  6. #6

    Re: Outboard Rebuild

    I went through a similar situation last year. I found the cost of rebuilding was more than the cost of a decent used outboard (60hp 2stroke) and I thought rebuilding would’ve been over capitalising. As well as machining bore and needing pistons and rings I also required a crankshaft rebuild. I was looking at spending a couple of grand on a 15 year old motor. I took the line of thought that putting a new outboard on an old hull isn’t overcapitalising on the boat as when the hull is past its used bye date i’ll Still have a good motor to bolt onto the next hull.

    Also if you tell us the make and model of your motor others might be able to offer more specific advice.

  7. #7

    Re: Outboard Rebuild

    Quote Originally Posted by fishizzle View Post
    I went through a similar situation last year. I found the cost of rebuilding was more than the cost of a decent used outboard (60hp 2stroke) and I thought rebuilding would’ve been over capitalising. As well as machining bore and needing pistons and rings I also required a crankshaft rebuild. I was looking at spending a couple of grand on a 15 year old motor. I took the line of thought that putting a new outboard on an old hull isn’t overcapitalising on the boat as when the hull is past its used bye date i’ll Still have a good motor to bolt onto the next hull.

    Also if you tell us the make and model of your motor others might be able to offer more specific advice.
    I have considered getting an second hand motor but good one the right hp, weight for an old hull and in good condition are thin on the ground. And on top of that you can't be sure of the condition unlike a professionally re built motor with a warranty. And the rebuild is still a good bit cheaper than buying a second hand motor from what I have seen. By overcapitalising I mean it's a lot of money to spend and still have an old boat and you may not get a reasonable return if you sell in a few years (not many people scrap their hull and keep their motor).

  8. #8

    Re: Outboard Rebuild

    in nearly 40yrs of boating I have NEVER seen a rebuild last for long..tolerances are too critical in outboards..they hold high revs for extended periods of time unlike an old two stroke motorbike engine that's revs on an off...don't blow a couple of grand on rebuild that will blow up anyway..get another later model second hand motor you may kick yourself in twelve months when it goes bang otherwise...rick

  9. #9

    Re: Outboard Rebuild

    I had a Johnson 4 cylinder 140 hp 2 stroke that had same issues with one piston and pot. Stripped it down and had the crank checked and it was fine so had re-bored (all cylinders) installed new pistons,rods,bearings and rings. Also got them to shave the heads and then I reassemble the engine and had the motor for another 4 years and used it a lot with no issues and sold it on to a friend who used it for many years later. 2 strokes are not that hard to rebuild and not that expensive for parts. When I brought the parts I shopped around and got the parts for the right price. Just do your homework. I ran the first 10 hours with extra oil in the mix and varied the rev's.

  10. #10

    Re: Outboard Rebuild

    Bilfisher,

    What you are needing is a REPAIR not a rebuild. Simply need a rebore to one cylinder and a new piston/rings. The rebore should cost about $50-100 and a new oversize piston maybe $150 (I don't know what engine you have so this could vary a lot if you have a coated bore that can't be rebored). A gasket kit too. Are you mechanically capable? The cost is very low. A shop will charge several thousand for the job. But its also critical to determine why the engine failed. If you don't, it will fail again.

  11. #11

    Re: Outboard Rebuild

    Quote Originally Posted by rickmarlin62 View Post
    in nearly 40yrs of boating I have NEVER seen a rebuild last for long..tolerances are too critical in outboards..they hold high revs for extended periods of time unlike an old two stroke motorbike engine that's revs on an off...don't blow a couple of grand on rebuild that will blow up anyway..get another later model second hand motor you may kick yourself in twelve months when it goes bang otherwise...rick
    I have rebuilt a lot of motors just to name a few 3 years ago i done a full motor rebuild on my Nissan X-Trail,Than i rebuilt a KTM 125 2006 model, WR250F, DRZ 400E all getting full rebuilds, i done a full rebuild on a Seadoo GTX that is for sale on Gumtree now and the new owner states in his add he put several hours on the new motor i rebuilt that is likely flat stick for a lot of its running time at high RPM

    if u rebuild a engine be it 2 stroke or 4 stroke to the right specifications and u do maintenance on time any rebuilt engine should last a long time it doesn't matter if its getting used to its full potential or idled along most engines made today are designed and made around racing they are than on sold to the public

  12. #12

    Re: Outboard Rebuild

    If your motor is no good to resell for some good valued money than your not at a loss that is the key to strip the motor your self, repairing outboards becomes costly and ineffective when u pay a shop to do the work they charge $110 per hour they actually charge $110 to remove 1 broken bolt believe it and yes u will likely snap a bolt i actually snapped around 20 bolts on one exhaust plate a welder is your friend

    mark everything put everything in zip lock bags and mark it as it comes off the block even if its just 1 bolt write down where it goes

    number your pistons and conrods to allocated positions unless u decide to install all new

    if u have a Johnson or Evinrude it gets a tad bit more complicated on a rebuild you will need to use plasti gauges to measure your shell bearing clearance

    if you go a head take pictures if u have questions ask on this forum plenty of helpful people on here combined is a wealth of knowledge if you don't know the answer its likely someone else does or has encountered the same thing

  13. #13

    Re: Outboard Rebuild

    Quote Originally Posted by gazza2006au View Post
    If your motor is no good to resell for some good valued money than your not at a loss that is the key to strip the motor your self, repairing outboards becomes costly and ineffective when u pay a shop to do the work they charge $110 per hour they actually charge $110 to remove 1 broken bolt believe it and yes u will likely snap a bolt i actually snapped around 20 bolts on one exhaust plate a welder is your friend

    mark everything put everything in zip lock bags and mark it as it comes off the block even if its just 1 bolt write down where it goes

    number your pistons and conrods to allocated positions unless u decide to install all new

    if u have a Johnson or Evinrude it gets a tad bit more complicated on a rebuild you will need to use plasti gauges to measure your shell bearing clearance

    if you go a head take pictures if u have questions ask on this forum plenty of helpful people on here combined is a wealth of knowledge if you don't know the answer its likely someone else does or has encountered the same thing
    I think it might be a bit ambitions doing it myself (how do I re bore a cylinder without equipment and experience)? Even if it cost a couple of K you have to consider the alternatives, ie a new motor for well over 10 K or a second hand one with potential problems and probably at least 5K plus the cost of fitting.

  14. #14

    Re: Outboard Rebuild

    Quote Originally Posted by BM View Post
    Bilfisher,

    What you are needing is a REPAIR not a rebuild. Simply need a rebore to one cylinder and a new piston/rings. The rebore should cost about $50-100 and a new oversize piston maybe $150 (I don't know what engine you have so this could vary a lot if you have a coated bore that can't be rebored). A gasket kit too. Are you mechanically capable? The cost is very low. A shop will charge several thousand for the job. But its also critical to determine why the engine failed. If you don't, it will fail again.
    I thought re bore/ new rings is called a re build? I am a bit confused when you say avoid a shop and then say a re bore will cost $50 - 100? Ie why would it cost anything if you did it yourself? Also how could you do it yourself without the equipment a shop has? In any case as I said elsewhere several thousand for a re build is still a lot cheaper than the alternatives.

  15. #15

    Re: Outboard Rebuild

    There are just jobs u cannot do your self if u have a one piece crankshaft that is pressed together its a specialist item/job, if u have a one piece crankshaft with shell bearings and u need it welded and ground to size than polished its a shop job

    you can do a lot of the work your self but those few big jobs are for the professionals, i don't mess with crankshafts i also dont have the tools to do boring and resleeving however honing a cylinder is one thing u can do quiet easily

    the speciality jobs are done by the professionals because they have the knowledge and equipment we are talking hundreds of thousands in machinery and measuring tooling

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