Here’s what my “thunderboat” looks like now

[Jeffrey Hammond]

Thanks Rich, these are great pics.
I had envisioned doing something like your corner magnets, but when I tested the fit, I found out that my placement interfered with the rear lip of my cowling. So I may have to move up to the next bulkhead to take advantage of two gluing surfaces for the boat parts. I do have a couple of pics of my magnet setup and the first test.
I played with the radio box position a little more and my box will barely fit crosswise…….better if I shave 1/16 off each side. I still can’t put it next to the #3 bulkhead ( right behind the motor) because the right side is reserved for my throttle servo and I’m not changing that. But the rudder servo could then move behind the radio box, and a long way from the pipe. The radio box would be closer to the pipe, but I cant imagine that the box would be adversely effected by the heat of the pipe. It is thick plastic.

 

[Rich Jones]

You will get it worked out. And once you’re running you’ll probably change one or more things. I can’t tell you how much I’ve racked my brain over stuff like this but I don’t need to tell you, you’re an airplane guy right?

I noticed you’re from Charlotte. I was down there last September at a car show at the Speedway. I enjoyed the town, went to the NASCAR museum, rode the electric train around, etc…

 

[Jeffrey Hammond]

I tried moving the radio box around, but ended up with it in the same place. I decided to make a small “heat shield” for my rudder servo. We will just have to test it. I tried to get a picture of it but it’s pretty congested in there. It’s just a piece of 1/4 pvc board that is between the rudder servo and the pipe. I don’t actually know exactly where the pipe will be as I don’t have my engine yet. Ordering it today.
I moved the magnet cowling hold down a little further toward the front of the boat and I think it will work there. It’s now about 3 inches from the stern.

 

[Jeffrey Hammond]

Yup, Charlotte is a good place to live. Great weather, water, people, attractions.
Do you play guitar? Noticed that in the pic background…..I have a few myself……
Need to cleanup the magnet holder a little. Then time to coat it with a couple of layers of finishing epoxy resin. The boat is getting closer to being done…..need to get a driver and a steering wheel and an instrument panel. Also need to finish off the air scoops…

 

[Rich Jones]

Yup, Charlotte is a good place to live. Great weather, water, people, attractions.
Do you play guitar? Noticed that in the pic background…..I have a few myself……
Need to cleanup the magnet holder a little. Then time to coat it with a couple of layers of finishing epoxy resin. The boat is getting closer to being done…..need to get a driver and a steering wheel and an instrument panel. Also need to finish off the air scoops…

Yes I do play guitar. Doing that right now actually. Mostly rock and classic rock.

All the little stuff at the end of the build winds up taking longer than you think. Then you have to seal the inside and outside, put the boat on the jig and get the decks on. THEN it’s time to paint.

 

[Jeffrey Hammond]

My “end of the build” isn’t that close. I still have to mount the motor, glue in the drive line, put in the gas bag, complete the exhaust system, drill holes in my radio box for servo wires, seal the inside and outside, put on the decks, and paint. Still a long list.
Did get the motor ordered today. I think I have all of the hardware to complete the boat. Worked only a short time today, working on the magnet hold down system for the cowling. Think I made some progress today, but also had another idea late today that I will try tomorrow.

 

[Jeffrey Hammond]

Still working on the cowling hold down magnet system. Got one step done today. Should be able to get the system finalized tomorrow. Mounted my rudder finally. Started sealing the inside of the hull today.
Then I got a surprise in the mail!!!! A brand new, Zenoah 260 PUM ! I now have all of the parts, except a throttle servo connection, to complete this boat. I’ll order that setup tomorrow.

 

[Jeffrey Hammond]

I also rummaged around and found a GI Joe guy that could be my driver! Now I need a steering wheel and a life jacket……

 

[Rich Jones]

I also rummaged around and found a GI Joe guy that could be my driver! Now I need a steering wheel and a life jacket……

He’s quite buff! .

 

[Jeffrey Hammond]

Ok, ok, I know he doesn’t look like your normal hydro driver, but if you cut him off in a turn, he will mess you up!

 

[Jeffrey Hammond]

Today I started playing with the motor. Of course, there are no instructions for the motor. And there are no instructions in the Zipp kits manual. So I’m on my own. I put the engine mounts in backwards. Had to figure out the exhaust header setup. Put that on 3 times. Had the header on backwards. Then I see this fancy aluminum bracket for something…….oh, it looks like it fits on this black gizmo on the side of the engine. And the bolt pattern fits up here. And the Zipp instructions have one picture where I can see the black gizmo is up on the front of the motor! Than the carb. Couldn’t figure out if the black piece on the motor stayed, or was replaced. Discovered that the Walbro screw pattern is different than the Zenoah pattern in that area, so both pieces had to stay. Then, which way is up? Had to go to zenoah exploded view to figure that out. Tried to put it in………frame of the boat in the way. Ok, enough frustration for now. Going upstairs. Critique the pic. Help.

 

[Rich Jones]

Today I started playing with the motor. Of course, there are no instructions for the motor. And there are no instructions in the Zipp kits manual. So I’m on my own. I put the engine mounts in backwards. Had to figure out the exhaust header setup. Put that on 3 times. Had the header on backwards. Then I see this fancy aluminum bracket for something…….oh, it looks like it fits on this black gizmo on the side of the engine. And the bolt pattern fits up here. And the Zipp instructions have one picture where I can see the black gizmo is up on the front of the motor! Than the carb. Couldn’t figure out if the black piece on the motor stayed, or was replaced. Discovered that the Walbro screw pattern is different than the Zenoah pattern in that area, so both pieces had to stay. Then, which way is up? Had to go to zenoah exploded view to figure that out. Tried to put it in………frame of the boat in the way. Ok, enough frustration for now. Going upstairs. Critique the pic. Help.

Sometimes you have to walk away for a minute, or a day, or whatever. The side the carb goes on is the intake side. The black piece that’s mounted there is the intake manifold. It mounts with two screws and there’s a gasket between the motor and the manifold. Then there’s another gasket and then the carb mounts on top of that with two long screws. I’ve put pics down below showing the orientation, but the needles are in front and the fuel intake and throttle attachment are to the back. The way the carb is sitting on the boat floor is the right way. And you can get rid of that black breather or stick in your parts box, I don’t use that. Also, remove the big idle adjustment screw and spring below the needles. You won’t need that. You will set the idle with your throttle set up and radio so that when your hands are off the throttle, the throttle is open enough to let the boat idle. Then you will close it with negative throttle to shut it off. My rule of thumb is to pull the carb arm just past the outside high needle screw and cinch down your throttle setscrew ( I think you mentioned you are using the cable). Set the inside needle(low) to 2-1/8 turns out. The outside needle (high) will be set to 1-1/8 turns out.

On the exhaust side, you have a gasket that kinda resembles a corky, paper material covering metal that goes between the manifold and motor. Then there are two orings (they should be 7/8) that seal between the header and water cooled manifold. There’s a lip on the header. One o-ring goes behind the lip and one goes in front between the water cooled manifold and header. So the lip is sandwiched with o-rings. Attach the header assembly just like you have it, I just wanted to make sure you understood where the gasket and orings go.

Looks like your coils are attached and the red wire between them is attached. The black wire should just be zip tied up with the red one. It doesn’t go anywhere unless you are trying to set up a kill switch.

Looks like you got the pullstarter on ok. Make sure that it turns the motor over.

 

[Rich Jones]

I am assuming that it’s the WALBRO WT-257 on the needle settings. It should be marked on the carb. Different carbs will have different settings but the 257 is the most common on stock tboat motors.

 

[Jeffrey Hammond]

Well, duh, the pictures of the motor are at the back of the instruction manual. I had forgotten they were there in the heat of the battle…….am also considering going back to the stock radio box. The plastic one puts my steering servo way back behind bulkhead 4. I don’t know now. Need to sleep on it.

 

[Rich Jones]

Well, duh, the pictures of the motor are at the back of the instruction manual. I had forgotten they were there in the heat of the battle…….am also considering going back to the stock radio box. The plastic one puts my steering servo way back behind bulkhead 4. I don’t know now. Need to sleep on it.

Do what you want but I wouldn’t be concerned with the servo going back there . Whatever you do, enjoy the process, don’t stress out over it. She’ll run for sure!

 

[Jeffrey Hammond]

Rich
Thanks for all of the info. I did leave out the exhaust gasket, the hard one, but the others are ok. Glad to hear the you left off the black megaphone….I’m going downstairs to take that thing off right now. It’s only half screwed on anyway. And yup it’s a 257 walbro.

 

[Jeffrey Hammond]

Some days building is easy….and some days that model will fight with you at every turn. The building session this morning was a battle. Motor in, motor out…..in, out….in, out. Carb on, screws too long, motor out, cut screws, motor in. Then I lost the exhaust gasket for about an hour. Then motor in, pinched a silicone o ring, motor out, reattached exhaust, motor back in. Now back to the radio installation.

 

[Rich Jones]

Some days building is easy….and some days that model will fight with you at every turn. The building session this morning was a battle. Motor in, motor out…..in, out….in, out. Carb on, screws too long, motor out, cut screws, motor in. Then I lost the exhaust gasket for about an hour. Then motor in, pinched a silicone o ring, motor out, reattached exhaust, motor back in. Now back to the radio installation.

Some days are like that, especially when you are new to gas boats. I was in the same place. You won’t even think about some of this stuff once you’ve been on the lake a few times. Friendly reminder, don’t forget to drill out your water inlets on the cooling cap to 1/8”. Check the exhaust manifold ones too although they may be already. Also you will want to open up your rudder to 1/8 as well if it isn’t already. I use Speedmaster rudders and I have to drill through them on gas boats, especially Thunder boats.

 

[Jeffrey Hammond]

Yup thanks for the 1/8 inch reminder. Haven’t done it yet.
Radio work today. Took out all of the pvc boards and replaced them with plywood and basswood. Remounted all servos, and made a new control rod for the rudder. Gotta connect it up to find the perfect location for the rudder servo.
Cut a 9 degree angle on the throttle servo mount to better match the angle of the post coming out of the throttle body. Flexible throttle assembly coming from Zipp this week, so I can connect it up and find out a) will the servo turn the throttle barrel, and b) what is the exact location for the servo to give optimal control over the servo.
Decided that the steering servo will go behind the radio box behind rib 4. Gotta do some balance checking to make sure this thing is not too ass heavy! Pics later!

 

[Jeffrey Hammond]

Also did a little work on the water lines today, and gas lines. Still got the exhaust ports turned around backwards, Can’t figure out how to set up this new gas bag. Need a routing for all the lines. I used some plastic lines for rear bulkhead up to #3, I think the frame holes are too small and pinch the tubes. So I got some plastic tube that had an Id more than 1/8 inch, and used them to run between the transom and the bulkhead number three. Then I tried to set up the flexible lines to connect these fixed lines and complete the setups. More work tomorrow. No idea how to mount the gas bag.