Neverdone

I have just begun a project that I might be in over my head with. I have found an old hydroplane style boat that measures 43" long and in the front widest part measures 22" wide. It had a few cracks and holes but I now have those fixed with fiberglass and will be having the boat gelcoated as soon as I finish making the top piece in the middle to cover the center which houses the motor and electronics. The boat was originally a nitro but I am trying to build this on a budget and funding is minimal so far total cost has been $20 which is what I paid for the boat when I found it. I decided I want to use a weed wacker motor and have recieved for free a 21cc poulan. Before I do any work to trying to put this in the boat I would like to know if anyone knows will this motor give it any speed or should I find something else? If it will work what should I use for a prop? It has a flex shaft and prop on the boat but dont know if it will work with this motor. I have pretty good knowledge of nitro and electric r/c cars and trucks but this will be my first boat so ANY help would be great!! Thanks

stempak

don,t know if you can get any parts for that motor? tunedpipe carb etc. it will be probably pretty slow stock and if it has a cover over the engine it will overheat not havng a watercooled head. on jims boat dock there are a couple sikk 25.4cc watercooled engines for 200bucks 300brandnew. they sport 5+hp with a tuned pipe. boat would probably do 50. the pulan 1.5hp might do 30 and might barely get the boat on plain. if the poulan had atleast a tuned pipe 2.5hp it would probably be ok but not being a watercooled head is a problem if the motor is not in the open air?

Hydro Junkie

FORGET USING A GAS ENGINE IN THIS BOAT
Unless I'm very wrong(and with scale style hydros that's unlikely) the boat in question is a Dumas 1982 Atlas. This boat, if built per the directions, isn't strong enough for a gas engine. I would look around on FleeBay for a .67 marine engine and go from there. I'm not sure what's up with that cowling, but to me it looks like _________________(Please feel free to fill in the blank). If you want a gas powered hydro, look into a Zenoah G231 or 260 and a hull designed for a gas engine. You will be a lot happier in the long run.

Neverdone

I know the cowling doesnt look great or well as you put it it looks like ____ but it isnt done and it still needs work all that is is cardboard with fiberglass laid over top and duraglass on that to smooth it. I will start to look for a nitro motor for it and see what I come up with. Who are some good companies that make marine motors that size? I know OPS and CMB but know nothing about their motors, OS doesnt make one that size they get up to a 46. You think that gas motor would just shred that boat or what? When I got that boat it had an "Irvine 61" in it I know nothing about that motor so I pulled it out especially because it is seized up. That gas motor wasnt going to be covered it would still be aircooled and I was going to take the head and get some work done so it would be water cooled also.

Justaddwata

My Feedback: (3)

Pick up the nitro motor you pulled and compare it to the motor your considering using. It is a bit like using a large diesel motor in a motor bike. Sure you could make it work but I think you will find it will be easier to do and perform better with the motor it was designed to run.

Having the weedy motor watercooled, ported, balanced, lightened etc etc wont give you much more than a very expensive better performing weedy motor.

stempak

ultimitly it.s your choice if you think you can get the gas motor in there go for it that is the way boating seams to be going because weedeater motors. are more user friendly to nitro and cheaper to operate! but they are both 2strokes!

piper_chuck

My Feedback: (12)

When installed in the proper boat, a gas engine can be simple. However, trying to convert a non-marine engine to marine use and then cramming it in a boat like this is going to be an exercise in futility. The engine will be too large, too heavy, and too underpowered.

stempak

you need a 20ccEI zenoah but they are not avaliable yet .they are for the nitro .60-120 size boats that gas motors won,t fit in

piper_chuck

My Feedback: (12)

At $339.99 for the aero version, that'll certainly fit into his desire to build the boat on a budget. Also, the aero version weighs a 33 ounces without muffler and puts out a staggering 1.7 hp at 8500 RPM?

Moving back to the budget theme, second hand K&B, OPS, CMB, and MAC engines are fairly common. I picked up a green head CMB .67 for a bit over $200 this spring. K&B and OPS engines usually go for less. These would be much better choices than trying to cram a gasser in the boat.

Flabum

I agree with Piper here, you may even be able to find a complete boat with a decent motor, radio and other gear you can scavange and sell the rest. There are plenty of ways to keep in budget and get what's needed.

stempak

Yep there was a brand new in the box k&b 67 on jims for 120bucks! also the carb on the 20ei supposedly won,t work and also has to be retuned plus motor mounts plus starter and tuned pipe need to be built from scatch. it sounds like they will or are available in europe if they are ever converted to marine use here? otherwise it would probably work inhis boat and if it had a pipe it would be at 2.7hp!

Neverdone

Thank you everybody for your suggestions..... One more question if I rig up a super tigre G-27 CX to be water cooled would that work? The head sticks out the top some to also air cool it some. It makes 2.5 hp at 30,000 rpm would that be enough power to make it move at a good pace I have had one of those donated for the project if I can make it work. If that would work are there any suggestions on a prop?

Flabum

I don't know if there is a water cooled head for that motor. If you stay air cooled, you will need to plumb some air to it. You could put side vents on the canopy to feed air. You will need plenty of air flow especially for a 30,000 RPM motor.

stempak

fastratfink has made a head for 20ei and the starter has been workedout

Flabum

Actually, I don't think a Super Tiger G 27 would be big enough for that boat.

Neverdone

Since I Started This thread the boat has come a long way I now have a Picco 80 in it with a full tuned pipe exhaust with silencer. It has been Gel Coated and am working on wet sanding it. It hasnt been worked on since around August but I will have it done this winter. Hope fully it will be ready to hit the water after the thaw...