We finally finished our 55 in Dumas Scarab with a 26 cc Homelite weed wacker engine. It ran fine but did not go nearly as fast as I thought it would. I was looking on youtube and some of the other 55's run in the 60MPH range. I would give ours maybe 20 MPH - The only reason I can think of is the prop. I have a 2.74 x 4.2 Bronze alloy prop on there which is the one I though goes on that boat. I did not polish the prop. It has a dull fishish. Do I need to polish it? Perhaps a different prop...

Thanks,
James

mate what work if enny has been done to the weedwacker . as far as i know thay dont have anough revs (8000 to 9000rpm)max. to get a boat of your size going . do your self a faver and spend $250. on a zenoah26cc or a sikk 25.4cc thay do rpm in the raing from 14000 to 18000rpm) . and it should go better . and even faster . or do some mods to one and it will go.
but you are right the right prop dose make a difrence . but im gessing your motor is the main prob if you want it to go .

or go all out and do a full mod for 400 to 600 and have a screemer:woohoo: or get a stoke motor and do some mods yourself lots are listed on this site . and realy if you are handy can do some ......ive tryed them and thay are not that hard if you understand what these guys are showing and doing..........

what pro are you running . is it me or dose that sound like a way to big prop from those dimentions you have listed....

but its great to see you giving it a go....

Just to be realistic, I will tell you right now you can forget about going 60mph with that mono with a weedeater motor...I would be shooting for 40 or so... would be a very respectable speed, and the motor would need mods and a tuned pipe. I am not saying this to discourage, but more so that you know what to expect and don't chase after something that is not attainable.

For the $ a stock Zenoah is definitely the way to go if you can afford it. It will overpower just about any modded Homelite you can build. Even with a cheapy cannister muffler it would bring that boat in the mid 40s. I would suggest some starter props like a Prather 270, 280, 472, 572. I don't know what prop you are using ...typically the 2.74 would be the diameter in inches which sounds about right and the 4.2 I guess is the pitch itself which would make it a 1.5 pitch ratio. It doesn't sound like a bad prop as far as numbers go...if you had a model number we could better help.

Some pictures of boat and setup would help a bunch also.

you will also need to learn how to balance and sharpen a prop.