ddaug

Here is the end product of my first build hope you enjoy
Theddaug

1QwkSport2.5r

Thats a sharp looking BSB, ddaug! Very nice paint job! What engine and prop are you using on your boat?

8MILLSNIPER007

A job well done!!! Hope you enjoy it!

Altered1

It does look good doesn't it !  I think it's time to ask for a vid !

8MILLSNIPER007

Yeppers!! Vid time!!

ddaug

Hey guys thanks for all your replies
The prop is just a stock prop from my hobby shop
The engine is a evolution .40 runs great still fine tuning
Hope to put it in the water on wed. will try for vid then
Oh ya my prop guard is from a piece of 3/16 X 1/12 aluminum worked great and looks good to
Next I want to build a reg. flat bottom and do it to look as real as possible
Anyone give me some tips on fine tune I can get it to Idle down nice with trim on radio but then cant get full throttle
I dont seem to have much adjustment on my cables
Any help would be great
Thanks theddaug

8MILLSNIPER007

The longer you can make your servo horn the more throw you will have. Then on the throttle side, the shorter the better, usally on the carbs there is only one hole though. Can you post some pics of your throttle setup? would be able to help you more if I knew what we are working with.

ddaug

Let me know if these pics work
Theddaug

ddaug

Sorry about the one pic here is the rite one

dadkins

Use a little longer servo arm to get more throw. then fine tune from there.

ddaug

Thanks dadkins
That must be something I will have to get all the servo arms that came with my servos those are the biggest that came with them
Theddaug

Got RPM

It is difficult to tell from the photo but it looks like there is another hole in the carb arm...move the clevis to that hole. If you can do that it will give you plenty of movement.






.

ddaug

It is in the last hole to the outside
Theddaug

Altered1

DDaug,

Like they said, long on the servo, in close on the carb.... you should be able to get a long servo arm easily and cheap.    Also try to secure all movement of your cable setup, as this will cause slack as well.

I'd consider changing the connection to the carb from a clevis to a ball link too.... not 100% necessity but will give you a connection with no slack at all, and is easy to connect and disconnect.

ddaug

Thanks altered1
I will try these options Oh ya the cables dont move at all that was my first thought also.
I will stop today and pic up parts.
Theddaug

dadkins

I was thinking the cable may be buckling also, but throttle control usually doesnt take much push or pull.
And Like Altered said - I now see a hole closer to the carb - moving it to that hole would move that throttle more.

8MILLSNIPER007

Just out of curiosity what remote are you using? Unless it is binding or your remote is setup incorrectly, you should be able to hit full throttle with the servo horn you have. Do you have a EPA setting on your transmitter?

8MILLSNIPER007

Also, You might want to consider setting up your steering with a push-pull system, the way it is now it might not give you very good steering especially at higher speeds!

*delete M i k e u p delete*

Plans for your airboat. Any avialable. I run electric only but you've done a great job and want to try electric. Thanks.I'll use a puller system, thanks.

ddaug

Hi Mikeup
I do have the plans that came with the boat but they are junk I basically laid my parts out and stated put where they fit.
If you talk to anyone that built the dumas big swamp buggy they will tell you the same. I found some good pics on internet just google it and you can find some good ones
Theddaug

ddaug

Ok guys
It hit the water yesterday it was awsome and all your help did it Idles great tops out great maybe a little bigger power plant for a little better speed but all in all runs great
I had a friend get a couple real short vids on his phone I will try to upload and see if they work. now 1 more ? for all of you.
I seem to be spitting a lot of excess fuel out of exhaust is that norm or can it be adjusted to get rid of some of that.
Thanks theddaug
Ok guys would not let me upload my vids it says 3gp is not supported anyone know how to change that like I said they were from a friends phone
The ddaug

Altered1

hey ddaug,

you can upload to youtube, photobucket and the like, and link to there.... just like photos.

The fuel out the exhaust will be the left over oil from the combustion process. This is normal. The oil acts as a coolant as well as a lubricant.

If you are not sure how to tune the engine properly, check out the glow engine thread. there are several mothods to tune

8MILLSNIPER007

Smoke and oil out the exhaust is a good thing, I know it can be messy but it is protecting the internal parts of your engine. You may have it running a little bit rich, the video you put up should tells us more on that. I am glad you had a good first run!!!

ddaug

Ok guys sounds good it ran real good so dont think e excess was anything
I will get better vids those were real short and not the best of focus. Again thanks so much for all of your help its been so great of all of you guys.
Theddaug

Mr Cajun Gator

ok ever needed to tune your motor
well i found this article carb 101 & have to say it works great
it was in a airplane forum i ran across so ill pass it along it helped me alot
"Here's the way that *I* set mixture on non-airbleed carbed engines (90% of the engines out there fit this category, but the theory is similar for air-bleed carbs). First of all, understand that the high speed needle has its main effect from 3/4 to full throttle, and the low speed needle controls everything from idle up to 3/4 throttle. It thus makes sense to me to spend the biggest majority of my tuning time adjusting the needle that controls the largest portion of engine running, right? Also, remember that there is a proper air to fuel ratio (mixture) that allows the engine to run properly. Too much fuel is rich, and too little fuel is lean. We "richen" the mixture by adding more fuel (turning the needle out, or counter-clockwise), and we "lean the mixture out" by decreasing the fuel (turning the needle valve in, or clockwise).

I start the engine give it full throttle, and lean it to it's highest rpm (peak), then richen it by maybe a quarter turn. Then with the glow plug igniter still attached, I slowly close the throttle to an idle rpm. At the lowest rpm that the engine will still reliably run, I then remove the glow igniter. If the engine dies immediately, I know it's too rich, and I then lean out the LOW SPEED NEEDLE by 1/8th of a turn (don't touch the high speed needle). Start the engine again, (and this is important) give FULL throttle briefly to clear out excess fuel, then slowly close the throttle again. Remove the glow igniter, and this time it may run a little longer before it dies, so lean the low speed another 1/8th turn. Re-fire the engine, give a burst of full throttle to clear it out, and slowly close the throttle again. remove the glow igniter and now notice that the rpm DROPPED a bit when you removed the glow igniter, but the engine kept running. We're getting there. It's still too rich, and you'll prove that by opening up the throttle and hearing the engine "blubber" then die. That's because excess fuel has collected in the crankcase during the rich idle, and when you opened up the throttle, the excess was pulled into the cylinder, making it WAY too rich. Supposed you were on a landing approach, and decided to go around, you throttle up but the engine "blubbers" and then dies (another thing we haven't seen, right?). Yep, the LOW SPEED needle was still too rich, allowing excess fuel to collect in the crankcase, just WAITING on you to try to go around so it could "LOAD UP", blubber, and die!

Keep leaning the low speed needle down until it idles well, but now, when you open up the throttle, it HESITATES instead of BLUBBERS. When this happens, you've lean it down too far, so richen it up 1/16th of a turn and try again. You know you've got the LOW SPEED needle right when you can fire it up, remove the the glow igniter, and the rpm doesn't change AT ALL, and you can open the throttle up, and it doesn't blubber or hesitate, it just runs!

The final thing you do is re-adjust the HIGH SPEED NEEDLE, leaning it to it's highest rpm (peak) and then richening it up maybe 1/8th turn to give it a slightly rich mixture. We also know that the fuel mixture will change in flight when you point the nose up (harder for fuel to travel uphill) and also as the fuel level in the tank changes. In both cases, a leaner mixture results, so we actually need to set the mixture a bit further on the rich side to account for this. While the engine is running at full throttle, CAREFULLY pick the model up and raise the nose to at least a 45 degree angle while listening to the engine. If the engine sags a bit, then you'll need to richen up the high speed needle 1/16th turn. Try it again, and when you can point the nose up and the engine doesn't sag, but maybe shows a slight GAIN in rpm, you know you've got it right.

Now the engine will be happy, and chances are will reward you with reliable running. If you've got one of the few engines with an air bleed adjustment for low speed adjustment, the theory is the same, just refer to your manual to see how to richen and lean the low speed mixture.