2006 Suzuki DF50 Impeller, Shift Linkage and Propeller Installation

READ TURNBUCKLE PROCEDURE HERE, TORQUES AT END:
I bought this boat in October 2024 just in time to winterize it. So, I am not at all familiar with the engine. Just learning it, although I have been working on engines since I was a teenager. I think I could do this job in about an hour now that I know how the shift linkage disconnects. I couldn't find any good coverage of this specific engine, so I figured I may as well record this so some other guy can have an easier time of it. So, this is my attempt to provide some procedure to remove the lower unit:

TAKING LOWER UNIT OFF: First, the brass turnbuckle (I'm calling it a coupler) between the upper and lower sections of the shift rod needs to be separated. In forward gear, take a picture of the threads showing thread # showing below the stainless lock nut for future reference. Note that the upper rod is reverse threaded, while the lower is standard thread. That means that tightening onto the lower rod also causes the upper rod to travel into the turnbuckle (tightens on both sides). You can't screw it all the way on the top one, thinking you'll then screw it onto the lower one (as I thought).

If you shift it into forward gear, both the brass turn buckle and the stainless lock nut should move downward and be visible in the space by the top of the leg on the port side. This allows easy access with 2 x 10mm wrenches. Hold the larger brass turnbuckle stationary while backing off the smaller stainless lock nut on lower side. Now, shift back into neutral before you loosen the turnbuckle off the lower side. You should be able to get a wrench on it while in neutral. Now back off the turn buckle only to the point it comes off the lower rod. Don't go any further or you will have the awkward and unpleasant job of trying to thread it back on to the upper rod. You may hear the gear box shift into forward as you wind the turnbuckle off. If it does, start backing off the 6 lower drive bolts, gently pulling the drive off to give a little more clearance (maybe 1/2 inch). You don't want to push too hard on the lower shift rod as you back off the turnbuckle in case something bends and then you're into pulling it apart (i.e. don't force it with the turnbuckle). Continue to unscrew turnbuckle with the added clearance just until it comes off the lower rod and no further. Leave that turnbuckle attached to the upper rod. If you thread it on the upper rod more than a few threads, you might lose too much adjustment. Unless you were having shifting issues because of turnbuckle adjustment, leave the turnbuckle exactly where it was when it released the lower rod. That way, when you thread it back on to the lower rod, you'll be at it's previous if you get it to where the lock nut was originally located.

PUTTING LOWER UNIT BACK ON: Leave shifter in neutral for now. Gently push the drive shaft up to passage to the engine coupler while guiding the water tube into the receiving grommet of pump housing. If your lower unit is still in neutral, twist the prop shaft back and forth to get splines meshed so you can move it into place. Start one of the 12 mm bolts so that the lower unit is prevented from falling off. Put shifter into forward to move turnbuckle into view. Gently move lower unit upward within about 1/2 to 3/4 inch of mating surface so that you can line up the lower shift rod with the turnbuckle threads. Be careful not to cross-thread! Count the partial rotations of the turnbuckle in case you turn it without engaging the lower threads. You can always back it off the number of rotations you counted without disconnecting it from the upper rod. Hopefully it threads right on to the lower rod. I just kept tightening mine until the threads bound and it was almost exactly where it needed to be. Check that you are engaging forward and reverse gears (by turning prop with your hand) with the same deflection angle from neutral on the shift lever. You can do some adjustment to the turnbuckle to get this right. When the lever adjustment is confirmed to be good, hold the turnbuckle stationary and tighten the locknut into the turnbuckle. I anointed it with grease for good luck.

These are the torques I used. Be careful they are the ones for YOUR engine. Be cautious of Google's recommendations as they can lead to stripped threads. If anyone reading this actually has a service manual, feel free to add them in the comments or verify these. I don't think you'll get into trouble with these obtained from various forum threads:
Torques:
6 x 12 mm gear case bolts: 16 ft-lbs
4 x 10 mm pump housing nuts: 6 ft-lbs
27 mm propeller nut: 40 ft-lbs
Since I also did my spark plugs:
3 spark plugs 11-15 ft-lbs for NGK DCPR6E 3481 plugs. With anti-seize I did 11 ft-lbs (don't over-tighten!)