no speed

[unclerico]

Hey all, I've been patching together a kyosho jet stream .16. The rebuild went fine until I actually put it on the water and discovered that it won't go faster than walking pace even at full throttle. The entire driveline has been replaced with kyosho parts down to the prop and the engine has lots of power but for some reason it just won't go. Thoughts, educated guesses and random shots in the dark will all be appreciated. Thanks!

[Ron Olson]

Are you getting a lot of cavitation? The props that come with Kyosho boats aren't very good as they have a lot of pitch. Try something like an Octura X-437. You may have to put a piece of brass tubing between the propshaft and the prop's hub so that it won't wobble.
BTW, those little engines love the nitro! I had a buddy with the Hydro-Jet with the same .16 engine and I dumped some of my 45% in it just to see how it would run. Boy, did it! The boat got to the point to where it was almost uncontrollable.
Worry about it running right first though.

Afterthought. Check to make sure all of the grub screws are on flat spots on the shafts and use thread locking compound on them.

[unclerico]

Thanks a million; the boat looks good sitting on the shelf but that's not what I had in mind for it. I'll put in a call to my lhs today.

[unclerico]

OK; finished the finishing work on the prop last night, hiked to the pond today in giddy anticipation. Unfortunately, the problem persists. Pace has picked up a little bit, but I can still jog faster than the boat will go (and I'm fat). Like last time even at full throttle it simply won't accelerate. Do I just keep going bigger on the prop or is there something else wrong? Thanks for all your help!

[Ron Olson]

You must be getting slippage somewhere, either in the driveline or the prop. Recheck all of the grub scews to make sure that they're on the flat spots of the shafts. If that checks out to be OK then try giving the boat a toos in the water to help it get up to speed.
The problem with the internet is that we can't be there with you to help out more to see what is really going on.
If you can adjust the strut, make sure that it's level with the bottom of the hull. Also, if the problem keeps happening, shut it down as you'll wont get enough speed to run water through the head and cook the engine.
you didn't mention what prop that you went to. a 37mm prop should do the job but the stock Kyosho prop is a 40mm but the high pitch is what hurts it.

[unclerico]

Yeah I know it's tough nailing down a problem when you can't even see it, but this forum has been an excellent source of help so far. Thanks to everyone! I just finished retooling the driveline and it looks pretty solid. The grub screws have a little loctite on them so tomorrow it's off for another run to see what happens. In reply to that last point, I'm now running an Octura X-437 (thanks to The Prop Shop for that one). It seems to be pretty good; the boat leaps away upon launch. Thereafter it settles to a gentle canter but hopefully tomorrow will be different.