goodwin1

I need some expert help from somebody.
I bought a this nitro boat [link=http://www.********.co.uk/4FA010357.htm]see it here[/link]
a little over a year ago, (Yes I know it is a bunch of crap and I should of checked this forum first) but I have got it now and would like to try and get it to run.
I have a little knowlegde with nitro by way of a couple of cars/trucks.
I have put about 3 tanks of fuel through it on a water cooled bench rig.
The engine seems to be running about the best I think I am gonna get it.
The problem I have is this. The factory prop that came installed on it broke in transit, I could not get a replacement easily so bought a metal prop of the exact dimensions etc..
When I launched the boat today it just crept around the pond and would not speed up.
The the engine will go full throttle but makes no difference to the speed of the damn boat!!!
Is it possible that the drive shaft is slipping somehow in the water as the connections between engine and drive gear are held with hex grub screwa!!.
Or is this metal prop upgrade causing this.
Any help would be greatly appreciated.
Thanks very much.
James

nothinbetr2do

did you balance,sharpen, and polish the prop? all metal props need it. here's a link http://manuals.hobbico.com/aqu/prop_sharp-bal_guide.pdf. and welcome aboard rcu

goodwin1

I didn't. I did read on here somewhere that balancing would be required but did not realise that without it being balanced and sharpened the boat would hardly move, can it really have that much of a drastic effect? and thanks for the reply!

James

Jerry Dunlap

I would suspect the propeller is the reason for the lack of performance. Just because a prop fits on the prop shaft doesn't mean it is the correct prop for that application. I would suspect the drive shaft is metric and it may be necessary to sleeve the shaft with a piece of brass tubing to allow you to run a prop with a 3/16" diameter hole. An Octura X437/3 or the Grim Racer 3 blade prop work on similar 18 size vee applications.

JD

goodwin1

Thanks for that.
When I got the prop ( cant remeber where), I checked with the shop that it would be compatible.I realise that wanting to make sales could mean that the information was wrong but the prop is a very tight fit on the shaft and needed to be worked on with some force but will certainly look into your suggestion and thanks again

James

f16man

Hold on to the flywheel and try to turn the prop to eliminate the loose or spinning shaft problem, if its tight then you are probably cavitating or prop angle is way off, What prop did they sell you?

goodwin1

Cant remember which prop it is but I will take some photos today and post them. There is an adjuster on the tail fin that moves the prop up and down. I have tried adjusting it so the prop is lower but makes no difference. It would seem as though when full throttle is applies the front of the boat does not lift.
I have tried the holding the flywheel and spinning the prop and it does not seem to slip, however when I am wondering if with heat the collet is expanding allowing it slip.
Thanks very much for your help.

James

Sean Bowf

You should be able to hear the prop spinning faster when you rev it up if it is cavitating (ventilating). Especially if the boat is near the shore.

I have never tried to put a metal prop on my boat that has not been balanced and sharpened to see what happens. But I am betting either it is the wrong prop, the lack of prop prep, or a combination of both of these that is causing your problems.

Sean

goodwin1

as promised here is a link to the pics, forgive the quality but had to take the pictues with my phone, once again thanks for all the advice
[link=http://www.goodwin123.com/test.html]pictures link[/link]

Jerry Dunlap

It looks like a Prather prop. If you remove it from the shaft and look at the back hub it usually gives some letters/numbers.

JD