remote control gas feed? - RC Groups
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May 23, 2010, 10:09 PM
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remote control gas feed?

im making my first remote control boat. im using a weed wacker engine, and for the rudder control using the tech off a RC boat im scraping for cheap.

how can i control the throttle on the engine?????? please help im stuck on this. ill post my whoel project when im done! thanks!
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May 24, 2010, 05:05 PM
Is it supposed to do that...?
Some guys use 1/4 scale servos, with a lever (horn) on the servo and a linkage rod to the carb throttle plate lever. You can make the rod from a bicycle spoke or other stiff, small wire. Basically the same layout as the steering servo, but the other end of the rod is attached to the throttle lever of the carb instead of the steering arm.
May 24, 2010, 07:28 PM
Registered User
ugh. im such a noob. please help.
so anyone wanna link me to the servo i need for a weed wacker engine? and can i just hook the servo up to the +/- that the tech froma RC boat that goes to the electric engine to the servo?
May 25, 2010, 07:10 AM
NeverAgainVolunteerYourse lf
nick_75au's Avatar
Hi Zeig,
What are you using for radio gear, It sounds like you're using a scrapped toy boat for the radio, which wont work, you need to go out and get, at a minimum a 2 channel radio, and at least a standard servo for the throttle and a higher torque servo for the rudder. Brand new 2.4 Ghz radios can be brought from china for $40-$60US shipped these days. (best ratio as less prone to RF interference),


Like this, (almost) any brand servo will be compatible with this unit.
May 28, 2010, 12:13 AM
Registered User
alright. ya i was gonna scrab a toy boat...

so thats the remote.. does that mean the control pannel kinda stuff is all inside?

and what kind of servo should i get then? woudl you mind linking me if you could? id really appreciate it. im gonna read up in the meantime. any good places?
May 28, 2010, 08:14 AM
Registered User
A search here should find some of the stuff you need. Otherwise there is RCUniverse, and Jim's Boat Dock. MGB has some excellent articles.
Jun 04, 2010, 03:48 AM
Is it supposed to do that...?
Originally Posted by zeig
alright. ya i was gonna scrab a toy boat...

so thats the remote.. does that mean the control pannel kinda stuff is all inside?

and what kind of servo should i get then? woudl you mind linking me if you could? id really appreciate it. im gonna read up in the meantime. any good places?
Sorry zieg, I should have figured the toy boat wouldn't be equipped with a decent transmitter(Tx) and removeable receiver (Rx). Read up on how RC systems work is great for lots of learning. You need a real Tx/Rx setup ($25 used), with two channels to control two servos ($40?), one for steering and one for throttle. There are lots of more experienced people on here who can offer better advice about what servo to use. Read build threads.
Jun 08, 2010, 04:33 PM
Registered User
great thankyouuuu ill read up as much as i can
Jun 22, 2010, 07:27 PM
Registered User
great news im starting on the Hull!

im just worried it wont hold, what does everyone else use to hold bind the seems of the hull together?

and what do they use for the outside to protect the wood from the water?

and last question, what can i do to keep water from entering where the drive shaft leaves the hull?

Jun 23, 2010, 03:36 AM
Is it supposed to do that...?
What material are you using to build the hull? I assume wood, thin plywood or veneer? I would seal the hull with a layer of light fiberglass cloth saturated with polyester resin on the outside, and just resin on the inside. Then paint with a good enamel.
Keeping water out of the hull? Try running the flex cable and original aluminum tube from the weedwacker if you still have it. Epoxy the tube around where it exits the hull. Try to have the engine end of the tube mounted just above the waterline if possible. Also put light grease in the tube. You will still get some leakage but not much. You can install self-bailers in the transom to remove water as well. hope this helps. I plan to build a boat like yours in the future.
Last edited by CedarTree; Jun 23, 2010 at 03:37 AM. Reason: typo
Jun 23, 2010, 05:49 PM
Registered User
sleepwalker's Avatar
You can use thinned two part 30 minute epoxy to seal the inside of the hull,as the engine area should be painted later with a gasoline proof paint.The Dupli Color 500 degree engine paints with ceramic are fuel proof.I haven't had any problems yet,or use the spray on truck bed liner.The outside of the hull can be coated with a finnishing resin ,such as West Systems or Pacer Z Poxy,using a playing card to get thin coats.You can also use a thin fiberglass cloth by misting a spray ahsesive above the cloth to get only a little on the cloth and then appling the cloth to the outside of the hull.Spread your resin with a card to get a thin even coat and repeat after drying until you get a smooth final coat.
Use a small piece of 11/32" brass tubing epoxied and glassed to the inside of the hull to exit the transom and go a few inches on the inside.Slide 5/16" tubing into the 11/32" and this will be your stuffing tube,to which your flex shaft from the weedeater will go into.Seal where these two size tubes meet, with epoxy so it doesn't leak there.If you ever have to replace the stuffing tube you just have to take out the 5/16".This way you don't have to run a teflon liner and keeping it greased will eliminate most of the water coming into the hull.Run your 5/16 tube to about 1/4" from the square drive on your weedeater and to about 1/4" in front of your ferrule.You'll have to gradually bend your tube to line up with your engines square drive.
Last edited by sleepwalker; Nov 16, 2011 at 01:07 PM.
Jun 24, 2010, 09:36 PM
Registered User
wow thanks that helped alot!

so baisicly i put a tube in the hull then put the driveshaft through the tube? what do i put around the driveshaft inside the tube to keep water fro seepign in? i ddint quite understand it, sorry?

also what battery should i get that will power my two servos and receiver thing

batteries- %2FBEC&idCategory=350&ParentCat=348
my receiver- King_2.4Ghz_4Ch_Tx_&_Rx_%28Mode_1%29

just as well..idk what servos i need... or where i can find the rudders..because their 50$ on that site...if ANYONE can help pleaase help lol.

im thinking ill need two props because its a 40" long boat about 13" wide..
Jun 24, 2010, 10:24 PM
Registered User
sleepwalker's Avatar
Grease the flex shaft with a good high temperature grease.I use a white marine grease and haven't had much water in my hull.The grease blocks the water from seeping up the shaft when the motor isn't running.When it's running the rotation of the flex forces water down the tube.A 6 volt NI-MH hump pack of at least 2000 mah will supply enough power and you can use a Y harness to hook up your battery to give you 6 volts to the rudder servo.Connect one end of the Y to the rudder plugin on your receiver,the battery to another end of the Y and your servo lead to the other.This will bypass the reciever and give you a full 6 volts to the 1/4 scale servo.You only need one prop on your boat ,unless you're doing a scale boat that the real boat has more than one prop.A Prather 270 or 275 are good props to start with for a weedeater engine.Zippkits has fairly cheap rudders and components and Joe will help you out.I'll try and find some places for the props and batteries.What make and size weedeater are you using?
Jun 24, 2010, 10:31 PM
Registered User
thanks! everyone is so helpful!

ryobi 4 stroke, idr the specs ill look it up soon.
i hate to ask this but when i read all of that i get confused, idk all that lingo quite yet. what battery do i need and whats being bypassed?

okay one prop works, im just afraid those 4mm props are to small!
ill check the zipp site for rudders.
Jun 27, 2010, 05:27 PM
Registered User
sleepwalker's Avatar
This kind of battery is what you need. It doesn't have to be that brand or be 2000 Mah as I earlier posted.It's called a 6 volt 2/3 A Nimh battery whatever brand or power rating you get.I'm assuming that motor has a 1/4" flexshaft,so props that fit a 1/4" prop shaft is what you need.You might have a tight fit getting that engine into that size of a boat,but give it a try.You asked what is being bypassed.If your reciever only alows 4.8 volts to go through it's circuits,plugging the 6 volt battery into the battery recepticle on your receiver would only give you 4.8 volts.By plugging the end of the Y harness into the steering recepticle on the receiver it lets the servo run on the full 6 volts untill the battery runs down.The rudder servo gets a lot of stress on it when turning,so the extra power will help. Here's a rough sketch on how to hookup your servos,battery,switch and failsafe.The sketch is of a receiver I use and your's may be different ,but has the steering and throttle places.
Last edited by sleepwalker; Nov 16, 2011 at 01:07 PM.

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