what size nitro engine is recommended for this model? (I posted same question on gas boats by mistake...sorry)

I'll delete the other posting for you.
That's a big hull for Nitro but a .90 should push it with no trouble. that thing could probably handle twin .90's but I won't go there.

Would a .90 make it zoom? .. and what speed can I expect it to achieve?

Otherwise what size gas engine (CC) would make it perform?

There are a lot of factors in getting speed so I can't give you any rough measurements. Which engine you buy, percentage of nitro, tuned pipe and prop all figure in.
If you want to go Gas, it's hard to beat the Zenoah G-260 (26cc) for the price.

Don't get me wrong here , as I DO run nitro's , and lots of them , but there are a few more things to consider when getting a nitro that big ...
1) does the idea of dishing out around $30.00 for a days worth of running sound appealing to you ? because that 90 ( and this is a single mind you ) will suck uop a LOT of nitro , and I DO mean a LOT .
2) Do you have a strong enough starter or plan on making/buying one ? ( bought , they are BIG bucks , not to mention the battery )
3) with that size hull , and a ZENOAH , you could probably run ALL day on about $5.00 worth of gas , and have no need for the super high torque starter , OR the battery ( as for the 90 nitro )

Again , don't get me wrong ... I LOVE nitro engines , but just trying to show you what you would be in for , if you ran a LARGE nitro in that .
( besides the constant tuning , verses the gasser , which , when set , is set ... no need to change dialy/hourly as with a nitro . )
And as Ron said ( which I agree 110 per cent ) .... all of what you asked , depends on a LOT .... setup , which motor , what per cent fuel , what prop , so on and so forth ...

Also , can I ask , what kind of speeds are you looking for anyway ? ( hopefully , not like those sellers on EBAY and are trying for 100 or more .... )

First of all I'd like to thank you guys for your help and input [8D]. !!

The boat is actually a 48 inch screwdriver... built to scale from plans by P. Simmons.
I got it from a friend who had built it ... just perfectly... still needs painting. (plywood construction). see photos.

He also ave me 2 nitro engines ... Magnum marine engines ... a .60 and a .91 XL
That's why I'm sticking to nitro engines since I have them.
Besides, Homelite & Zenoah gas engines for RC are not available here... I'd have to go research weeders & chainsaw spare parts dealers & modify for application.

Nitro fuel is relatively cheap here. I use it on my HPI savage truck, and other .20 OS powered off shore boat, with great results.

I'm definitely not looking to brake the sound barrier (LOL) ... nor get to the 100 mph mark.

I just want a thrilling, water biting boat... and get the best with what I have.

What prop would you recommend for use with either engine?

Pompebled... an rcuniverse member from the Netherlands, [sm=thumbup.gif] had sent me this picture of the screwdriver.

If anyone has more pics of this model, is welcome to post them here. Or directions to where they could be found.

anyone...? please...[sm=frown.gif]

The Magnum 91XL is the same motor as the ASP 91 which I have in a 42 inch sport hull. It is on a tuned pipe and I love the setup. These motors start EASY and idle with the best of them. Put the 91 in it, don't go beyond 10-15 percent nitro as the head button is not made for high nitro. I run 10% in mine. It will be a fun boat and will last for ever. The manufacture of Magnum, ASP, and CS motors is in China but the workmanship of the motor inside if you tear it down is of the best period. Great sport motor. Good luck, my grand children love this boat and it is sometimes a handful.

Regards Curt

Thanks Curt,


Any recommendations on what prop to use ? (I am clueless about props).

What is the consumption of your .91 ? What size tank you have in ?

The engine does not use the amount of fuel of say an OPS Marine 90 at all but burns maybe an oz a minute or little more.

Props, wellllllllllll If you are going to have it fully submurged as in the pic, a 457 or 455 Octura X series . I use a larger prop but only because I have the the boat on surface drive. Use a !/4 inch cable with the 3/16 inch stub shaft on it. Break in the motor if it is new a little rich but with plenty of rpms in short runs for the first tank or so then lean it up some. don't get the motor tooo hot early on but they need to get warm enough to seat the piston to the ABC sleeve. you probably know that already since you are a car guy . That motor will last you lfor ever if you take care of it and parts are very cheap for them. you made a good choice for a sport motor as I would not take for mine as a sport motor period!!!!!!! Regards Curt

thank you Curt,

The props you suggested are for the .91.

What prpo would you suggest for the .60?

And if I go with a gas engine ...what CC would you recommend? and what prop?

The prop I currently have on the boat (see pic) was homemade in cast aluminium with the .60 in mind... Have no idea what size is it... Do you have an idea how can I figure out it's pitch?

Again thanks for your input.