ob nut

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Thompy, if you ever make it over to Cincy, let me know. I'll take you over to the CMBC pond and we will dial in the boat... [link=http://www.cincymbc.com/]Cincy Model Boat Club[/link]

Thompy

If I can make it! Going to college and working trying to put myself though college is pretty rough, not alot of spare time in there. My dad actually got this for me as a birthday present, thats honestly the only way I got it..... lol.... but thats beside the point. I've got a few questions before I start this thing up in the near future. What prop(s) should I go with, and where can I purchase pre sharpened and balanced ones? As far as the motor mount, its the Prather one, and from looking at it, it really doesn't look like it would be to easy to adjust, which motor mount do you guys prefer. I've looked at the octura and du-bro ones, but I'd like to get some good opinions.

ob nut

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I'm getting my props from Mark Sholund at [link=http://www.props4u.com/]Props 4 U[/link]. Mark can provide prop information. Good props to start with are: X440, X1440, X437/3, X440/3. No particular order either. I've used the Dubro motor mount in past. Still have those on a few boats. Using a mount from [link=http://precision-boats.com/]PBR[/link] on my 3.5 race boat. Thinking of switching to a mount from [link=http://www.seismicracing.com/comersus/store/comersus_listCategoriesAndProducts.asp?idCategory= 103]Seismic Amigo's[/link]. If you are just going to play around, either the Dubro or Octura will do just find. I like the Dubro mount since the plastic mount will break when water debris is hit. Otherwise the lower unit needs to be replaced.. [>:]

Thompy

I was looking into a three blade prop, but I know since I'm new to this nitro boat thing this might sound crazy. I've been working around real outboards for awhile and came across the prop questions many times. I had to make a choice myself. I have a 1960 Johnson 18HP on an older aluminum vee bottom hull. I had to replace the prop during the restoration of the motor. I had two choices a 2 blade, and a 3 blade. The 2 blade was for heavier boats, so it was pitched less and was a smaller diameter, the three blade a bigger prop for a lighter boat. The point is to get the motor to run at its recommended WOT range. The three blade was the best choice, kept the motor at the right RPM. Also, after seeing people try props and try props and again try some more, I've seen that the more blades, the more torque better hole shot, less blades less torque but you gain on the top end. Take a bass boat for example. If you wanna jump outta the hole you might opt for a 4 or more blade prop. Wanna run 70+ with a 225 outboard go with a 3 blade. Not to mention on a larger boat, such as a run about or something of the rather. Wanna pull skiers? Go with more blades. The object is to get the right combo to keep the motor at its recommended WOT range mind you, so no matter if you go with 3 blades or a crazy 5 blader, you still want to keep the motor running where it likes.
Anyway I know this is long, but here me out. More blades in the water more drag you are creating less efficent the motor can be if your looking for top speed. Mind you this regards to FULL SIZE BOATS, not scale models, the real deal. Is this just crazy, or can this same concept be carried over to the model boat world?

ob nut

My Feedback: (1)

Believe a 3 bladed prop gives better bite in the corners. But each hull acts diffently, even in the r/c tunnel arena. Try the 437/3 first, then move to a 438/2 or 440/2. A 440/3 would be a wise choice also.

While at the 2004 IMPBA Internats, a guy there had a 4 bladed prop on a .21 DV. I asked him where it came from, ABC custom made for him. Then he pulled out a large 6 bladed prop.. He entered 12 classes and took 6 #1 plates home with him that week. Think he knows what he is doing. You may have heard of him: Ernie Lafleur.

Thompy

Well these engines aren't the huge firebreathing v-6's and older Johnson 300 HP v-8 two strokes either, so I can see why. Must be how these little engines are. What is the RPM range for these little things anyway? I'm waiting on some parts, and I'll look into a prop or 2 so I can get out and try it . Not in a big hurry though, still awfully cold here.

ob nut

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Per the K&B site, the standard 3.5 has RPM up to 23K. I just received a new MAC .21 OB and it's listed up to 35K. When spring hits, drop me a line and we can meet up at the Cincy pond. It would be wise to join IMPBA. The club will allow a guest to run once or twice, but for insurance reasons it would be best to be a member of IMPBA..

Thompy

I know this is a noob question but...... When I'm looking down on the starter cone from the rear of the boat it turns clockwise to make the prop turn counter clockwise which is the way the prop is designed to spin. Is this correct way to start this motor? I know your always saying it should turn counter clockwise, but should the cone and the prop spin this way? Also, the nut on top of the cone is a 7/16th nut, can I use a drill and a socket to start the motor?

ob nut

My Feedback: (1)

I had to visulize how the motor is started Yes, the starter cone needs to turn clockwise so the prop turns counter-clockwise Ouch, that hurt the ole brain cells. I've seen drills setup to do exactly what you ask, but have never tried one myself.

ob nut

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Here's a shot of the 4 bladed prop I spoke of earlier.

Thompy

Whoa, thats crazy. Alot of blades for such a little amount of space. It's amazing what people will do to squeeze out a little more speed or handling. Its like those 5 blade props on real boats, someone has to have a crazy idea to get it started and test it till it works. I've got my drill set up to start it off the top nut. Just an adapter to run the socket. It turns it fine, I'm just waiting till tomorrow to see if it'll turn it fast enough to get it start. No doubt it'll turn it over. I just wanna hear the thing run, if even for 2 seconds, I just wanna hear it. I'm DYING to take it out, but it'll be awhile before that happens. Suppose to snow here, and in your neck of the woods for that mater ob nut. The LHS, well not local, but the only hobbyshop here for 100 miles stocks absolutely NOTHING for boats. I'm talking nothing. They sell if I'm not mistaken like 2 boats, and thats it, they don't even sell the fuel to run them. Im going to have to get everything off the web, which means Imma get shanked with the ole shipping fee's.

Thompy

Oh, and ob nut... I'd love to join IMPBA I'd think that would get me going in the right direction for sure. There's a couple of problems though. Number one. College and work while I'm here in Portsmouth takes up just about all my time. Number two. Coming up at the end of spring quater, and during the start of the summer I'm transfering to Ohio University in Athens, Ohio to finish my undergrad. Does't get any easier after the lol. Going to transfer AGAIN to Capitol in Columbus to go to either graduate school, or Law school then take the bar exam to practice some type of civil law. But you can bet my tunnel hull will be with me the whole way. As long as there's water I'll be doing something on it. May it be fishing it, or driving this little dandy.

ob nut

My Feedback: (1)

Figure out what you need and get it at one place to save on shipping. I know all about the LHS not being so L.. If I have a large
order it'll go to Tower Hobbies.

Check www.impba.net for clubs that are in the area which you will be moving to in the future.

Thompy

Thanks a ton. I do have to thank all of you guys again, not to often you find a place such as this that is so insightful. Again I really apriciate all your help along the way. Hopefully one of these days I can return the favor.

Thompy

What plugs do you guys run? The plug looks bad when I put it on the glow heater. Tell you the truth it looks like the origional KB plug with the idle bar.

ob nut

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I use MC9's in all my boats. If you have a 12mm motor (with the stock combustion chamber), you'll need either a short plug (K&B S1) or use two plug washers. Don't get any with the idle bar on it, it's not needed. The K&B L1 plug is also a good one to use.

Thompy

I disassembled the whole motor last night down to the bare crank case just for the heck of it, I guess I used the excuse to see if everything looked good. It did, I might have to do a rebuild soon, but I don't know how soon I'm going to have to rebuild. If you move the piston veryyyyy slowly to TDC you get some blow by, but when I took the motor apart the piston was very snug at the top of its stroke. I was also surprised to see a big "13" stamped on the crank balancer as well. After put it ALLLLLLLL back together I was curious and put a couple of drops of fuel in the carb, put the glow driver on it, and hit with the drill. She fired and ran for about 2 seconds till the fuel had ran out. As far as I'm concerned she'll run great, unless she starts to heat up thus expanding making the little blow by a big deal. Now my question. I'm always going to have one.....lol Do you have to get rebuild parts such as the piston and sleeve from Mecoa directly, or is there some websites that offer aftermarket parts, or even genuine K&B parts?

ob nut

My Feedback: (1)

There are some good places to buy used K&B parts, just need to find them. Fleebay is also a hit and miss. I've never heard of aftermarket piston/sleeves. Too costly to make. With the 13mm motor, you will need a long plug. K&B 1L or MC9's are good choices to go with.

Thompy

Finding them is the hard part... lol... K&B's website is down for a month or so for their "annual" vacation so it looks like i'm going to have to be on the hunt. It doesn't NEED to be rebuilt right now, I'd just like to have the parts for when it does. Most hobbie shops don't really carry parts, and if they do, I haven't found em yet. If ya'll have any good places to try let me in on the secret. Its got the origional plug in it so obviously I'll be changing that out, btw, thanks for the plug recommendations.

ob nut

My Feedback: (1)

Rod Geraghty, Jim Irwin, Al's Hobby shop and Phil's Hobby shop would be some contacts for K&B parts. The two hobby shops are listed on the web. I might be able to locate the email and phone numbers for Rod and Jim. For bearings, go with RaceCraftBearings, quality Swiss bearings from Ron.

Thompy

I've got my boat all put together, ready to go just waiting for the water to warm up, or at least the air temps. I've got a quesion on fuel. My brother flies model airplanes and has some Morgans Cool Power fuel. Its 15% nitro, and their website says it contains 17% oil. Check out this website and it'll give you all the specs, http://www.morganfuel.com/cp_blends.htm and give me a heads up if its ok to run through this KB. If not no big deal, I'll just find some. Just wondering if, so I don't have to go buy some fuel, he has gallons of it around here.

Thompy

Anything fella's, or is this question and answer stuff getting old.... lol.... J/K

ob nut

My Feedback: (1)

Everyone has their opinion on fuel. Some will run Morgon (Cool power) and other fuels in their boats. I pay too much for my equipement to run fuel, for what I consider, that is designed for air or car. Cool Power, Omega and many others fit into this catagory. It may just all be hype, but I sleep better thinking I'm running fuel designed for boat needs - Byron, O'Donnel and Wildcat are the fuels I've used over the 20+ years of running boats. General thought is that boats need 18% oil. Since the fuel your brother has 17% oil and is only 15% nitro, you should be just fine using this. If you want to liven up the motor, run 50% or higher.

Your questions aren't getting old or tired, keep them coming.

Thompy

Well, I know this boat is gonna be a little quicker than I think, and seeing how it is my first boat I should take it easy till I get the hang of it. I'll op for more nitro when I'm used to the handling characteristics etc. etc..... I'll go for a little more when I feel fit if you know what I mean. Thanks for the valued opinion as always.

Thompy

I picked up a Graupner Carbon Fiber Prop on ebay for about a dollar, well a bout 4 dollars including shipping, and I need some help. Its almost identical to the X-440 as its 40mm and only hundredths of an inch off in pitch. I picked it up as a "learning" tool till I'm ready to purchase props to play around with and learn to sharpen and balance them. My question is.... when I took it out of the package I placed it on the propshaft and when I spun the motor the blades hit the water pickup tube. I've sanded away some of the back of the hub to see if it'll fit that way with no luck. It still hits but is better than when I started. I sanded away so much that I'm right to the edge of the blades. Am I just out of luck here, or is there anything I can do? It will fit a little better if I can remove some of the material in the slat that the drive dog fits into, but I still believe it won't fit even if I preform this procedure. Please tell me this will work as the prop that came with the motor is an OLD Octura 1240 plastic screw that is chipped in 3 places and useless.