RE: Need Help First Boat Ever Undertaken
Your Webra is a marine version, not a converted aero motor. It is a strong runner, uses low to no nitro fuel.
Do not go above 10% or 15% nitro with it without lowering its compression with a head shim, or it will have pre-ignition problems. They are built as high compression alcohol engines. I love my collection of them. Mine that I have pictured is a .60 version that I have recently restored, but I have all kinds.
Webra's are economical to run, very strong and last forever. It is when you start adding nitromethane to the mix is when fuel consumption starts to go way up on them. Running straight alcohol and oil is the way to go, and only add nitro to help with idle.
An alky motor is designed to make the same power as a nitro motor, only more economical. They use a different head design, and slightly different port timing. The rpm's will not be as great as a nitro design, but you can count on more grunt out of them, meaning a larger, more steep of a prop can be used.
Adding a header and a tuned pipe will help any two-stroke motor to gain power. [link=http://www.macspro.com/prodline.asp]Here[/link] is a popular supplier of boat headers, however Webra does offer their own in chromed steel and also aluminum fabrication. Take time to download the Adobe Acrobat catalog at the link, it is where the boat headers are hiding along with dimensions and notes.
You can forget your 1/2gal fuel tank...that would be good for two full seasons running the Webra with only one top-off of fuel.[sm=teeth_smile.gif] A 10-12oz tank is the norm for what you have for a good 20-30 minute run. SLEC makes nice sturdy fuel cells, and would be a nice replacement if your interested.
Making your own fuel for them is very easy, it does not have to be hobby shop fuel. Just 80% methanol and 20% castor oil is all you need at home to do it. You can also change to a castor/sythetic blend to help keep exhaust mess down if you wish.
Adding 3% acetone to the mix will take the place of 5% nitro, and will help starting and idle characteristics. If you're interested in mixing your own fuel instead of buying hobby shop fuel, here is a handy fuel calculator for determining amounts and percentages of any size batch: [link=http://www.nitrorc.com/default2.asp?Introduction=http://www.nitrorc.com/fuelws]Fuel Calculator[/link]
Pictured is the factory fuel recommendations, and if you need more help with documentation I will be glad to help. [sm=thumbup.gif]
If you can provide more pictures of it, I can determine what model number it is for you, plus part list and diagrams. Good to see you aboard!