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Dumas scarab 55" build

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Old 03-02-2019, 05:47 PM
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sleeper607
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Default Dumas scarab 55" build

I am finally building this thing, the key to this will be I am doing it on a budget. Not HGTV or any of the how to car shows budget but more like a sub 100 bucks or maybe sub 50 bucks. So I bought the hull 2 years ago and still don't have any funding available for this, so I figured if I built it on a budget that would be the only way it would ever get completed. It needs a motor and exhaust, servos, prop shaft and tube along with some misc. stuff that would have to fit within my budget. So my criteria for a motor is it must fit my budget, be water cooled and be able to sit low in the hull so I can run the lid, also I don't want to change the rails currently set up for a big nitro. I will say that I have a plan and I am making progress. I will say I am cheating on the budget a little since the motor was given to me but anyone could have the same motor for free also. Another cheat is that I bought used servos a while back and don't remember what I paid but it was only a couple of bucks so technically I could account for that.
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Old 03-03-2019, 05:50 PM
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The motor is a featherlite 21cc weedeater motor, the cooling fins have been cut back and a 1-1/2 copper pipe cap fits as a cooling jacket. I am waiting on more parts (should be here next month) and need to make a hardware store run at some point. But I also have to make motor brackets to mount the motor to the rubber mounts.
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Old 03-06-2019, 11:25 AM
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If the hull has 5" space between the rails you could have left the front part of the green shroud on that has the recoil starter in it..The 21 cc won't get much speed and I've found out that Poulan made these in 18cc,20 and 21cc and and later went to a 25cc. Some of them were labeled as 20 and 21 cc and were actually 18cc motors. Don't have much power ,even as a weedeater.Did you tap the exhaust to accept the plumbing fitting ? What is that on top of the cooling jacket ? You could put a larger venturi carb on the engine to get more rpm out of it. I did that with a 21cc and 25cc trimmer I used in the yard. A carb with a little larger venturi but only up to 11.11 mm or it's too much for the little engine, You don't really need the choke on the carb as you can choke it with your finger.
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Old 03-06-2019, 06:14 PM
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The problem with trying to run the recoil is that it runs off the flywheel which will not let it sit low in the boat. So I have the copper cap on top of the motor with 2 o-rings at the plug and I will probably just rtv the bottom I have to tap or solder on some nipples for water. I may need to run a bigger carb but we will see how this one goes. So I picked this motor instead of a homelite or other weedeater I have laying around since this is a undesirable motor to me so I won't care if it spits its guts. The exhaust I ground drown the fitting and it fit perfect but could have tapped it then I will sweat on some tabs or make a bracket and put some springs to hold it on, and maybe a nipple for water. So my plan is now that the motor is stripped of flywheel and ignition is to run an adapter and glow plug and run it on nitro which will keep it light and pickup some power.
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Old 03-06-2019, 06:55 PM
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Here's a thread that deals with gas /glow conversions. GAS/GLOW HOW TO....
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Old 03-09-2019, 06:23 AM
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I have read that thread, that was one of the inspiration behind doing this.

The story of my life to end up buying 200 bucks worth of stuff for a 100 dollar budget because you buy or get the wrong thing.

Murphy's law of the further away from a parts store you are will be directly related to the number of times needed to visit said parts store to finish the project.
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Old 03-09-2019, 08:16 PM
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Originally Posted by sleeper607 View Post
I have read that thread, that was one of the inspiration behind doing this.

The story of my life to end up buying 200 bucks worth of stuff for a 100 dollar budget because you buy or get the wrong thing.

Murphy's law of the further away from a parts store you are will be directly related to the number of times needed to visit said parts store to finish the project.
I know what you're talking about. I buy most of the items I need for a boat or an airplane online,but do use things from hardwares that are for other uses and reinvent them to whatever project I'm doing.I'd often go into Lowes and look for stuff and when I'd tell the associate what I was going to use it for I got funny looks or they'd say that can't be used for that. I even have one guy in the hardware dept that if he sees me coming he goes the opposite direction.Latest thing I bought at Lowes was sliding door finger pulls,which I cut the back off and will use them as front and rear vent hole trim on my Expresscraft VX Rocket Probably will put some screen on the inside of the vents also.The white patch on the transom was where a wrap to center tuned pipe exited. I patched and filled it in and will cut a hole on the left transom to be the exit.

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Old 03-11-2019, 04:40 PM
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Well I made a hardware store run today and I think I have pretty much everything I need to put this together. Aside from making the wrong size glow plug adapter work and a nipple for the cooling head, or end up buying them. Then there is a list of everything that needs to be completed.
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Old 03-11-2019, 05:01 PM
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Originally Posted by sleeper607 View Post
Well I made a hardware store run today and I think I have pretty much everything I need to put this together. Aside from making the wrong size glow plug adapter work and a nipple for the cooling head, or end up buying them. Then there is a list of everything that needs to be completed.
Also don't forget to glue an ample supply of pool noodles in the bow and on the sides of the hull.Also some pieces under the hatch cover in case it gets knocked off in a roll or flip.Most stores have them out already.
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Old 03-11-2019, 05:13 PM
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If I even find an untouched Scarab KV 38 I think I'll paint it like the first one I had.The radar arch broke so I never replaced it. I'd also put a bow rail on it like on the first.It was built back in the early 80s and the original owner put an OS 77 VRM in it.I sold the engine to a collector and later sold the hull and hardware to someone else.

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Old 03-15-2019, 03:50 PM
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This is what I have in mind for decals on mine.
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