So are you running a square drive flex setup?
The back of your collet is a whole 1/16" away from your T bar. You won't be able to remove the collet insert unless you pull the motor out of the hull. If your running a round flex, you have problems. I like around an inch or so from the collet to the stuffing tube in my boats. Brian

What did you do, you could have spread the engine and radio box further apart. Tapping the radio box is going to be a pain. I can tell you your boat is not going to plow even If you move the engine 13 inches forward of the transom with a stock 26 zenoah. Give your self some room to make it easier to service the boat. You must have long flexible fingers Or something! Lol. The most important thing is that your having big time fun doing it and at the speed your building, moving things around won't be a problem and is part of the processes with a developed hull. I'm hooked keep it going. Also I know your ahead of the thread but make sure the hull is not twisted when you glue the deck on. You can also lay up your hull and deck lighter at the front and heavier in the back to get the cg were you want and move the engine forward or just a heavier radio box and trim tabs would help with you current lay up. The shaft gets a little longer and adds weight aft as well.

Hello people, thanks for the words. Your certainly both right on a couple of things there. I ended up with a tad over an 1/8" at the collet which as BMAD pointed out will complicate changing it out. To be honest though, it takes all of 1min to drop the throttle linkage and pop out the two transom end engine mount bolts. The motor just swings up then which isn't a prob as I've done it a couple of times now. I'm already planning another build which will see the radio box abandoned for water proof servo's and an enclosure just big enough for the receiver and battery. Has anyone here done that and has any pics?
Taping the far back of the box was a pain in the backside indeed I've since cut a neat section of deck out around the box lid, and would like to secure it down with some small black anodized zdus fasteners if they're available. Something flush anyway. I think velcro would just blow off mid run.
Bar those little problems, the only other one I had was when filling the tank. I use one of those neat little Dubro hand crank pumps to fill up. When I first tried though, it would fill up a little bit, and then start blowing out the hose on the tank fittings. I figured it had to vented, so put a third line in the tank as a vent line with a brass cap and tiny hole. A bit crude but it seems to work fine and doesn't spill any. I also soldered some barbs onto the tank lines.
Trim tabs were out, along with turn fins. I just didn't want them. I like the clean look, and figured for a sport hack I should be able to get away without them if the CG and hull work as a team correctly.
After it's first run yesterday, I can't even begin to tell you about the smile I had on my face. Got down the park, pulled the cord and threw her in. After babying it around for a bit, I started pulling the trigger a bit harder. Man, this is addictive. No bobbing up or down, or rolling side to side. It's real nice from a newbie point of view. The only thing I noticed, is a slight hesitation to rev when going from part throttle to full. It's like a little stutter. It's only momentary, very very brief. I'm wondering if a smaller prop may help this. I went out with a 7014 two blader. I'll take someone to record a vid with me next time to post up, but it won't be for a couple of weeks now due to work.

Coagulations, now take a brake an enjoy that one for a while or you will find yourself building all the time. It is beyond addictive and been known to cause marital problems.Lol.

Nice job on the boat building !!!!

Try opening the low speed mixture screw a quarter turn, if it makes it better go with it. If it makes it worse turn it back the original quarter and another quarter turn and test again. That's what it sounds like to me. I run my screws low speed 2 1/4 turns and the high speed is 1 1/4 and my boat has no dead spots. and you wanna see a chocolate colored spark plug insulator and that means she's running the right mixture. Use a clamp on those mixture screws they vibrate loose.

If the carb is a #644 the settings should be 1 1/2 and 1 1/2 - I don't think that clamp will not work on 644

some info Starting point carburetor settings (High/Low)

www.modelgasboats.com/magazine...buretor-tuning/
www.bonzisports.com/zenoah/carbs

Hot Rods rigs the water proof servos to the stringers and puts the receiver in small Tupperware box and his throttle rig is really neat and trick. The water proof servo is programmable with a 3/16 flex shaft straight to the carb butterfly shaft. Hopefully he or his son chimes in.

Yes, we have used waterproof servos ( self sealed and factory ) for years. The battery boxes are NOT Tupperware however. They are a very rigid polystyrene food container called "Lock-n-Lock". They have a 360 degree soft silicone thick gasket that is captured in the lid, and 4 very strong closure clasps. Unsealed and sealed in seconds. One hole in the box for wires, totally sealed.
Our direct throttle link from servo to carb shaft is 1/8" ( absorbs vibration better than 3/16" ) speedometer cable flex.

Thanks very much for the pics, links and carb information guy's. Pretty well on par with what the Komatsu manual states.
Very motivating stuff Hot Rods, those food containers look very neat and functional. Looks like your onto a winner there.

I will get dad to take a few pics of my mono setup for you. Being 40" long, space was limited and careful planning took place before drilling. Here is a old pic for now. The setup now is mostly finished and is just as clean, but a bit tighter. Very happy with the out come.