mixture controls on twin hydros

[Don Ferrette]

O.K. so keeping on the twin engine theme, for those out there running twin hydros what are you using for your mixture control?? Anyone having success with 3rd channel control on your twin? If so what set up did you use?? B)

 

[Mike Byer]

That reminds me of another unfinished project, I was using 2 of Andy's needles hooked together and synced controled by 1 srevo. never got it in the water, but it'ds on the list. my boat likes about 7.5 @40" on the flow meter, what does yours like

 

[TimD]

2 x fuel doctor type valves on a single servo is the most common setup down here. A flow meter is essential!

Tim.

 

[shoboat]

Twin Owners,

What is essential is a good laser temperature gun,so you can see what

if any of the engines are leanng out. The flow meter is another good tool.

And a good set of matched propellers of course.

Thanks,

Mark Sholund

Props-4-U

 

[TimD]

And a good set of matched propellers of course.

Shameless :lol: :lol: :lol:

 

[shoboat]

Hey Twin Owners,

Just ask Mitch, He knows everything.

 

[[email protected]]

Has anybody ever tried running two differnet engines at the same time???

Mine have always been matched but I'm curiuos if it would work?? I guess since they all turn different RPM's it wopuld be impossible for it to work??

 

[TimD]

Mark,

I wasn't having a shot - It's just my warped sense of humour! I appologise if you took offense - it wasn't intended.

Tim.

 

[shoboat]

Tim,

I wasn't offended at all. I was trying to be funny also. This hobby should be

fun.

Thanks,

Mark Sholund

 

[Don Ferrette]

Ok getting back to the topic - needles (not props, that's next). With every 3rd channel needle I've tested I cannot find 2 that will give linear (equal) flow change between them when they are adjusted remotely, something that is essential on a twin. I will admit I have yet to try this on a pair of CMD/Kalistratov needles but so far all others have failed this test. So if you are using remotes on a twin, how much accuracy in keeping them in tune with changing the needle settings are you getting?? Or are some just getting lucky hitting the sweet spot from time to time....... :blink:

 

[Mitch Graber]

Don,myself and a buddy are both using CMD needles on our CMB 90

twins,we are the only ones down here in Fla.that are doing it at this

time,"that I know of".I know all the "experts" have said it WILL NOT

work.....but after last weekend in Miami I am leading the points in

X Hydro for Dist.3. I set the needles up the first time on the rich side

and checked them with a flow meter and it took over 30 clicks leaning

it down before they started to flow differently,I have yet to lean it down

more than 15-20 clicks so they are still running in synch.Maybe I got

lucky getting 2 remotes to flow so evenly?I don't know.Mitch

 

[Mitch Graber]

Mark,do you own and run a twin?Or are you just flapping your

lips as usual????Who would try to run a twin without matching

up the propellors??Laser heat gun?Don't need it,or are you selling

those now too?

Rodney,last year I ruined a sleeve in one of my black/gold

EVO motors,put in a '98 model purple head EvoII motor,"that came

from Don F.", in just for giggles....the boat ran great..people could

not believe it when they saw it at the races.The motors were night

and day different in compression also.Mitch

 

[Buckshot]

Don, I'm also very currious as to what everyone is using. I building an 80 twin SGX right now myself.

-BUCK-

 

[Don Ferrette]

Thanks for the input Mitch, I may take a pair of the CMD needles off the parts wall & do some tests. Also I'm also glad that purple head 90 did you right, I "massaged" it a little before you got it. Hmmm, seems I've set a few guys in here up with some of my "good stuff"

 

[AWaddle322]

Don,

I thought at one point that I really wanted to race twins so I bought me a couple (4 to be exact). I have tried every brand and motor cobination that is possible. I like you believed that I was smart enough to make 2 remote needles work. The only way you can get to remote needles to work is to have then flow the same and we both know that 2 motors on a twin never want the same amount of fuel.

To get the performance that you want the inside motor is always richer than the outside motor. Know think about how remote needles work. If the needle does not go thru the hole inside the needle valve the exact same amount they flow differently. As you get one needle further away from that hole each little change makes a much coarser jump on flow meter. I guese someone with much machining experience could come up with a way to ofset this but i was never able to.

What I found the best was one standard non remote control adjustable needle and one that was adjustable by the radio. I have heard that some people out west use a 4 channel radio so they can adjust needles indiviually.

My standard practice for running a twin. Leave non radio adjustable needle along. launch boat. richen adjustable needle if boat was not at speed I thought it should run. If it got faster fine. If i Felt that I had not gotten none adjustable motor rich enough I would drive at 3/4 or 7/8 throttle or at close to speed That i knew the boat should be running. I guess what I am getting at I had better luck matching the motors this way. Not always the fastest but the motors were generaly matched as well as I could get them and I alway felt Matched motors was always best. rich ,lean or perfect.

My beliefs of a twim today:

speed = no problem

good handling = no problem

speed and good handling = NO WAY

If you have not figured it out I probably want be racing a twin any more. Got tired of getting beat up by the single boats that had speed and handled good.

Most of the fast twins in our area use two none radio adjustable needles or the way listed above.

Sincerly,

Allen Waddle

 

[Don Ferrette]

"........Most of the fast twins in our area use two none radio adjustable needles or the way listed above.

Sincerly,

Allen Waddle"

I hear ya Allen. All the twins I've run always had seperate non remote needles but can't keep wondering about 3rd channel like all my other boats have. We all know the inboard motor needs more fuel, the base setting would be richer & if there were 2 needles out there with linear matched rates you would be in the ball park. I guess Mitch got lucky with 2 remote needles but perhaps the single remote needle is the better option. Now with that in mind, what's people's opinion on which motor that gets the remote control- inboard or outboard side?? :unsure: