http://www.youtube.com/watch?v=Uzoqz...e=channel_page

Mild Language warning : I accidently Swear a Once


As you can see in my Vid above.. Everytime my Aquajet goes out the flex shaft comes loose and it stops dead..

Are there any Mistik ways of keeping it in !!!!
I Tighten the Grub Screw... and it stays solid.. get it out on the water and in 20secs... it pops out again and the grub screw is still in place...


Any help would be great !!!

if you could post some pics of your set up . a pic is worth a thousend words in this case .

not knowing much about the problem, I'd suggest Loctite thread locker. The grub screw is just working itself loose due to vibrations.

you could also sorder the tip out the cable so theres somthing more sold to grab on to

I might do everything as suggested to make sure it don't come out..... but then again... with the 700 size motor it might just shear off like it did last time....

what size flex are you useing ? it should be .150 or larger for a 700 and what size prop?

Hi
I have worked on a AJ with a 700 motor and later a 800 motor .These boats will run good when set up.
I'm wondering just what kind of coupler you are using. The most successful set screw couplers have a lot of screws that bare down on the flex shaft. The ones I most often make use nine screws. A single set screw can work if you do everything right . Use Blue Loctite on the set screw. Solder the end of the flex shaft about a half inch. File any excess off. File or grind a small flat on the soldered flex shaft where the set screw will make contact. These things if done will let you get on with running your boat. Either .125 or .150 flex is just fine with 700 power and 12 or more cells.
In watching your video ,it look like you boat is just barely hooking up after a long start. You prop may not be right to get you on plane. What prop are you using?
n.h.schmidt

Image of the Internals as requested..
Despite the looks of the water cooling it is remarkably effective...

like i said worth a thousond words .. is the flex cable braking lose or the set screw on the motor or prop shaft. the fact that it only has one screw and im bitting the motor shaft doesnt have a flat spot . and use blue thread lock

Its letting go on the Propshaft side of things.. Its the actual flex bit that comes undone.. not the actual connectors.. So both Connectors are secured solid but the Flex section on the propshaft connector pops out...

I am going to try the filed solder solution with some Locktite and see....

I am suspecting that the grub screw is vibrating a little and letting go even though its done up tight...

it looks like a type that is glued in not set screws . to make sure how many set screws are on the hole flex copuler?

One.. So a total of 4 Grub screws...
Each end has a Grub screw that connects to the Motor shaft and the flex shaft, the other end connects to the flex shaft and the propshaft.. The connector that holds the flex shaft and the propshaft keeps letting go...
Right where the purple Circle indicates is where it is letting go constantly...

Hi Magnat,

The fact the motor stays cool, is most likely because it doesn't have to work very hard...

What prop are you using?

My 12 cell boats are on the plane in a matter of feet, with a Graupner 45K.
The motors are cooled like the one in the picture; brushtab and cancooling and they need it.

There must be something off in your set-up.

Regards, Jan.

its also probly staying cool b/c you haven been able to get a full run in . but yeah do the sorder and thread lock the set screw and if you can add a set screw to the cable end 180 from the other it will help alot. the flex cupler i use from ose uses 4 set screw on one end to hold the cable

I have a Polished Brass 36mm sharpened and balanced prop ? I think ??? but for the moment I am using the Stock Aquajet Plastic Prop until I sort out the flex shaft issue... I would
hate to loose a valueable prop if the worst happened and I lost the boat...

Hi Magnat,

36mm is too small, no wonder it takes sooooo long for the boat to get on the plane.
I don't know how big the stock prop is but you should run a 40mm two bladed prop as minimum, 42 is better, 45 mm would be the quickest version I guess (all Graupner 2318.xx series).

Regards, Jan.