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  1. #1

    1200 non-pv rebuild help

    I've had my boat 2 years its a 2005 Yamaha lx210 with twin 1200 non-pv engines and I've blown one up . I found a replacement engine and I'm going to rebuild both of my engines .

    I've rebuilt several car engines and this will be my first shot at a boat/jetski motor so any tips would be appreciated

  2. #2
    steve45's Avatar
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    Welcome aboard, 05lx210!

    Did an oil line come off? That is very common to Yamahas, and will happen to all of them eventually if the hoses aren't upgraded.

    It's important to determine what caused the failure. If it wasn't an oil line, then pull the carbs apart and check for trash, which would make it run lean. Then, ideally, you would want to pressure test the crankcase to see if there was a leak that caused a cylinder to run lean.

    Here are some things I've found helpful:

    It is very difficult to remove the PTO coupling from the crank unless you heat it with a torch. They make a tool to engage the flywheel teeth so you can unscrew the coupling. If you don't want to buy it, a lot of people put a bunch of rope into a cylinder to keep the piston from moving.

    That engine has a bunch of head bolts of different lengths. I've found it helpful to mark them prior to taking them out so you get them back in the same place.

    Disassemble the exhaust system. There are some water ports inside the expansion chamber that need to be inspected for blockage. If they get plugged, you'll burn up the rubber exhaust hoses.

    Also, use YamaBond on the crankcase halves. Pressure test the engine before you put it back in the boat. Buy good parts. You're better off doing it yourself most of the time. There are some good overhaul shops, but there are some lousy ones, too.

    Regarding the oil lines, replace with polyurethane hose. Make sure the hose is longer than the original hoses. Secure them with .025" stainless steel safety wire, two wraps around the hose, then twist the ends together. While you have the inline valves out (called 'check valves' but they really aren't), pressure test them. They should only flow in one direction (look at the arrow on the side) and they should open at about 4 PSI. If they leak, the engine can get flooded with oil during long term storage. Test the oil system on the bench before you install it. Mount the pump in a vise, rig up a supply line above the pump and fill with oil. Attach a piece of 1/2" ID hose to the drive tang (remove the coupling for this), then insert a short 1/2" rod into an electric drill. Put the rod into the hose on the pump and spin the pump CCW to fill all the hoses prior to installation on the engine. You can backflush the oil filters with solvent to clean them, just dry them before installing them.

    Buy a service manual!


  3. #3
    jeffg426690's Avatar
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    You mentioned a replacement engine, is it an OEM motor or a SBT motor? Generally speaking SBT has a reputation for building crap motors with very sloppy tolerances. Not easy to tell them apart until you break it down, sbt will have their name stamped on the crank rods is a dead giveaway.
    You can probably find a service manual online for free or cheap. I printed mine and put it in a small binder.
    Mikuni kits only on the carbs (yes, you need the kits) and its cheap insurance to replace the jets. There is a fuel return mod worth doing (in the yamaha How-to stickies) and also consider rejetting with the Oside carb recipe (also in the stickies) although it requires FA's or a modified airbox for proper airflow. Not sure how the recipe applies to nkn-pv motors, maybe someone else can chime in on that.
    Take your time, cleanliness is godliness as with all rebuilds. If you've done 4-stroke care motors, this will be a breeze.
    Also a good idea to get the cylinders mic'd at a shop to get appropriate pistons, recommend ProX pistons for OEM rebuild.
    Yamaha head gasket & carb base, after market is ok on the rest.
    There are tons of really good rebuild threads on here with all the answers, even a pv motor thread will help - only real difference is the pv's and different jugs.

  4. #4
    As far as I can tell no oil lines came off I'm not sure what caused the failure yet

  5. #5
    The engine I found a a 99 model stock engine.
    Actually its 3 different engines.
    The jetski shop I bought it from had 3 jetskis the owner pulled the engines apart and sold me the parts that are still good...ish
    All 3 had been blown.

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