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On The Fly Manual Mixture Linkage-HELP

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On The Fly Manual Mixture Linkage-HELP

Old 08-19-2007, 03:04 PM
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mopartybob
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Default On The Fly Manual Mixture Linkage-HELP

Rather than using a third channel remote switch and servo(but still using a remote mixture valve),Has anyone thunk up an idea using a bellcrank type system that would allow leaning of the carb mix when at 3/4--WOT,whereas it would toggle back to it's origional mixture at 3/4 and below....I think this set-up would be more beneficial than using a servo,(you could never over-lean the mix) and max performance is there when you transition between 3/4-WOT,to cool the engine down,just run at 3/4 throttle fer a bit....but for the life of me in my sober mind [:-],I can't picture the set-up..[&:]....help please... oh, this is what i'm working with...thanks cmb.21 w/3rd ch. carb mounted needle plate...Thanks to James(TopFuel4430) Clegg at Ovalexpressracing.com
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Old 08-19-2007, 03:37 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

Why would you want to run at less than 3/4 WOT?
Old 08-19-2007, 03:58 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

LOL...Chuck your killin me here....[:-],Lets just say IF you did want to cool off your engine ...you could ease off to say7/8 of WOT....as to like maybe when a turn is negotiated.... you really would'nt want to run it leaned at it's peak all the time would you?? plus i could have a brew in my other hand,thus fidgeting with another knob is like well ..you know....fidgeting with another knob.....[:-] I picked a heeluva day to quit drinkin.....
Old 08-19-2007, 05:33 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

I hear ya, it's a bit tough to fidget with a knob while you're also driving. [X(] Obviously you wouldn't want your pit person fidgeting with the knob (in all seriousness, it's actually not permitted in IMPBA for anyone else to touch the transmitter). However, many transmitters do have the ability to map the 3rd channel to a wheel that's conveniently located on the handle, so you can use your thumb to control it. This is perfect for those drivers who are all thumbs.

Moving on to the beer problem, you could get one of the devices in the attached photo. With this, you could down two beers hands free while you're driving.

And finally, I usually stay WOT (was thinking of another set of letters, but it'd probably get censored, so I'll save Ron and Matt the trouble) unless I'm hopelessly behind, or way out front. If you're having cooling problems at full throttle, you might be too lean, are not getting enough water, or are running too hot a plug for the fuel/compression ratio, or some other cause.
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Old 08-19-2007, 06:26 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

now we're on to sumthin here chuck...,Is this item namba/impba approved, and if so,is the pit man allowed to reload you.....???[:-]
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Old 08-19-2007, 06:44 PM
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Sean Bowf
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Default RE: On The Fly Manual Mixture Linkage-HELP

I thought...that it was lean at launch, then richer once on plane. Is that not correct. I currently don't have a 3 channel setup on a boat...but have done some reading on it, and it appears I might have misunderstood something???

Sean
Old 08-19-2007, 07:24 PM
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Dan S
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Default RE: On The Fly Manual Mixture Linkage-HELP

The other way around Sean,

you start at close to perfect, if you fall behind or if you want to gain a lead in first few laps or last few laps you go leaner to get stronger and faster. once your ahead, you can bring her back a bit to cool her down.

Dan.
Old 08-19-2007, 08:08 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP


ORIGINAL: Sean Bowf

I thought...that it was lean at launch, then richer once on plane. Is that not correct. I currently don't have a 3 channel setup on a boat...but have done some reading on it, and it appears I might have misunderstood something???

Sean
If the engine doesn't have enough grunt to get the boat on plane then the lean may be needed. Otherwise, rich at launch then lean it out.
Old 08-19-2007, 08:10 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP


ORIGINAL: mopartybob

now we're on to sumthin here chuck...,Is this item namba/impba approved, and if so,is the pit man allowed to reload you.....???[:-]
Not sure if it's approved or not. Refills are only permitted for enduro racing. For normal heat racing, you only get the "fuel" you launched with.
Old 08-19-2007, 09:34 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

My reponse is there is alot of times when a racer is out in front by half a lap and can ease off and take it easy. Also there are alot of conditions that would warrent running at 3/4 throttle. Now this whole idea of this needle I dont really understand but there are times when WOT is not needed.


Paul
Old 08-20-2007, 10:12 AM
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Default RE: On The Fly Manual Mixture Linkage-HELP

Aaaaaahhhh...The power of beer..., I figgered out a way to toggle the mixture lever off the throttle arm...., by runnin an "Z" shaped linkage directly off the throttle arm,attached to a paper clip style slider,(to minimize throw)will allow actuation of the mixture lever as described in initial post....yea-yea-yea I know, post pics and results, I wanted to do it this way so's I would'nt have to be fiddlin with a thumb dial,and having to glance at my Tx panel to check mix settings and possibly over lean /overrich the mix by MISCALCULATING,....[:-], nOW TO TRY TO CLEAR IT UP FOR pAUL....engine runnin rich at WOT= S L O W...... engine optimally leaned out= FASSSSST.......
Old 08-20-2007, 06:19 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

ORIGINAL: Dan S

The other way around Sean,

you start at close to perfect, if you fall behind or if you want to gain a lead in first few laps or last few laps you go leaner to get stronger and faster. once your ahead, you can bring her back a bit to cool her down.

Dan.
Well...I am pretty confused now. I did find that post I read, it was on another forum, but made by someone that frequents this forum. Anyhow, here it is:

ORIGINAL: jetpack
First let me say that an onboard mixture control now allows me to be 20 times more efficient at my pond testing. I can test props, pipes, and all sorts of things without having to re-set the mixture each time I make a change. Before, I had to reset the needle sometimes 5 times to get it perfect.

Now, I can just launch, bring the needle to a super rich setting and then dial in the correct mixture in a lap or so. Specifically, here is how I use the Mixture control:

Some boats require a fairly lean setting to launch that big prop. OK, then I set the mixture control slightly lean, which will allow me to get the boat up quickly with that big prop. Many more times it is easier to get that big prop up with a setting that is a little more on the rich side of the needle. Just as soon as the boat is up on pipe, I immediately return the mixture control to a super rich setting ( the engine will not even be in a clean two cycle).

I then gradually move the mixture control knob leaner and leaner until the engine just starts to clean out. At that setting, you will make MAXIMUM POWER. It does not seem possible that the engine should be on the rich side of the needle to make maximum power, but ALL our testing has shown that to be true.

At the start of the race, you may want to go a couple clicks leaner so that you will get instant response when you cross the starting line. BUT, just as soon as you get around the first turn, richen the mixture the two clicks that you leaned in, and leave it that way for the rest of the race. If you find that you are either in control of the race or behind by an insurmountable margin, you may want to richen even a couple more clicks. This is the safest way to finish the race.

If you will use this method to set your mixture control, you will ALWAYS have a perfect needle (WHAT AN ADVANTAGE). How many times have I seen people use the mixture control EXACTLY like an onboard FIXED needle. They never change it unless the boat is much to lean or much to rich. What a waste of a valuable piece of equipment!

Another misuse of the mixture control is by those with a wheel radio and a knob at the top of the transmitter. The ONLY way to change the mixture control is to take your hand off of the steering wheel while your boat is running all over the place. I might suggest that you either change the mixture control channel to the thumb wheel by re-programing your radio OR by changing the wires from the mixture control pot to the thumb wheel pot. A simple change of the three wires from one pot to the other is all that is required.

As for suggestions about the best mixture control, I will say that I have only used the OS Mixture control on my own boats, but have seen MANY use the Bob Violett mixture control successfully and I have heard that the mixture control that Competition Marine sells is also very good.

I hope that this simple explanation of the efficient use of a mixture control will be helpful.....
Be sure that you use discipline while applying this method and you will ALWAYS have the perfect needle on all your boats!

DON'T USE A MIXTURE CONTROL LIKE A FIXED NEEDLE or YOU MIGHT AS WELL USE A FIXED NEEDLE.

Thanks has to go to Marty Davis for this write-up!!! Thanks Marty, I have refered to this myself a few times and thank you for your effort!!!
Not trying to start anything...just trying to learn...

Sean
Old 08-20-2007, 07:15 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

hey sean,this is the first time I've ever used one and I did also read that same post by jetpack and another link that was providided by P chuck in that forum,I can see the advantages of the thumb wheel set-up, if you keep changing props and fuels,and being a racer....(I'm not) just looking for speed... anyways,let me put it in my perspective from which I have experienced as you and others have as well....ever get your boat runnin nice and fast just to flame out after 2 laps...?,just to find out that it needed to be richened ,which then took some performance off but in turn burned the whole tank?? get it .......what i'm after in this set-up is this,but first, let me outline the application...this cmb .21 is going in my ABS (glass re-inforced)31" nitro vee,runnin thru speedmaster hardware,into a aquacraft 42-55 prop,this thing is gonna run out of lake,or eyesight real fast,before i have to back-off the throttle so I wont have any time to fidget with a thumbwheel, I need sumthin that will be pretty fast in reacting to throttle variations....It's just out-of-the-box thinking for my particular needs and application,and more likely than not ...wont work for others.......[:-]
Old 08-20-2007, 09:21 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

Sean,

What jetpack is explaining is pretty close to what I told you, except he starts richer and then gradually leaning as he goes or need it.

I on the other hand said to start close to perfect (on the rich side), than use it when required.

Dan.
Old 08-22-2007, 04:30 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

well I got it rigged up to where it actuates a total of 1/4 turn lean at WOT,now I just need a big stretch of water to test and post results,....[:-]
Old 08-22-2007, 04:35 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

it would be better if you adjust it so you can go 1/8 either way.

Dan.
Old 08-22-2007, 04:56 PM
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Default RE: On The Fly Manual Mixture Linkage-HELP

thanks dan,the mixture lever rotates 1/8 turn from mid throttle either way= 1/4 turn total adj......so at idle i'm runnin 1/8 rich and at WOT 1/8 lean...mid throttle is where i'm settin the needle at just about where she starts clearing her throat.....dont really want to do no testing on dry land in case case things go AWRY.....[:-] yes my mix lever is longer than my throttle lever.......
Old 08-25-2007, 11:41 AM
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Default RE: On The Fly Manual Mixture Linkage-HELP

here's pic's of the set-up...should work....??
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