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rotax 447 problems

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neo

New Member
Joined
Jul 23, 2010
Messages
1
Location
griffin ga
I just got a rotax 447 and it will run like a champ without the prop but will stall when i give it gas when the prop is on it. can anyone help?
 

Horsepower

Member
Joined
Oct 17, 2009
Messages
15
Location
St. Maries, Idaho USA
I just got a rotax 447 and it will run like a champ without the prop but will stall when i give it gas when the prop is on it. can anyone help?
Sounds like a fuel problem,maybe too lean when under a load. I would clean carb and try it again.You could try choking it as you throttle up if it stays running most likely fuel starvation. Good Luck Randy
 

Richard6

Well-Known Member
Joined
Aug 14, 2010
Messages
703
Location
Plymouth, MN USA
Neo,

Most likely the problem is that you have the idle mixture set to lean or you have the idle RPM set to low or both.

If you have a owners manual for the engine, look to see what the recommended idle RPM should be. Otherwise, I would set the idle RPM at 3,000 to 3,500. These engines do not like lower RPM.

The idle mixture adjustment on Bing carb is an air screw. As you screw the mixture adjustment screw out, the idle mixture is leaner. (more air - less gas).

With the engine warmed up and at idle, try adjusting the air adj screw in 1/4 turn at a time. Allow some time for the adjustment to take effect. Have someone watch the tach as you do this. You want to turn the screw in or out until the engine reaches the max idle RPM. Then you turn the screw about 1/8 to 1/4 turn in. This will give a slight rich mixture and should cure you engine wanting to die on opening the throttle problem.

If the above does not work, I would disassemble the carb, clean all the passages and check the float height. If the fuel in the bowl is to low, it could cause problems.

Richard
 

recmob

Well-Known Member
Joined
May 8, 2010
Messages
73
Location
FL
If you set your idle to 3,000 - 3,500 rpm, you'd better have 'good' brakes.

As a Rotax repair station for the last 12 years, the first thing you should do is set the carb settings back to stock - meaning the jets, needles, everything. Then see how it runs. If the engine has not been run regularly, might not be a bad idea to do a carb rebuild kit either. Also check the fuel pump pulse line is not cracked or collapsing.

All above said, the 447 is temperamental on idling compared to the 277/377/503/582's. Standard Rotax idle should be around 2,000. However I've found all the 447's on aircraft I've built (around 30 aircraft with 447's) it likes to idle more around 2400 rpm. Anything lower then that, the 447 after idling for 30 seconds or so, the rpm will drop off and the engine will want to die. This seems to be only for the 447's though.
 

nickjaxe

Well-Known Member
Joined
Aug 14, 2009
Messages
159
Location
England
Has it ever run ok with this prop,

Just wondering if maybe it has to much pitch for the engine???

Nick.
 

King Chicken

Active Member
Joined
May 20, 2013
Messages
38
Location
Oak Grove, SC
Nick

I'm just getting it flying, about 3 hours on it.
RPM's are where it should be for climing out. 6450
All temps are within normal range. EGT 350 CHT 1050
Just burning about 6 gallon a hour.

Larry
 

nickjaxe

Well-Known Member
Joined
Aug 14, 2009
Messages
159
Location
England
6 galls per hour WOW thats heavy...1050 is a bit cool in my book suggesting an over rich jetting...which could also cause your bogging on opening the throttle,

Think I would strip the carb and check all the jets and needles to make sure there at the book setting.

Nick.
 

nickjaxe

Well-Known Member
Joined
Aug 14, 2009
Messages
159
Location
England
What kind of RPM is it cruising at and is that 6 gall fuel burn at cruise RPM,

If you dont know what your STD jetting should be...I can point you to some on-line web site that should give you that info.

Nick.
 

Dana

Super Moderator
Staff member
Joined
Apr 3, 2007
Messages
9,336
Location
CT, USA
6 gph is absurd for a 447! If it was running that rich it should be fouling plugs horribly. I would look for a fuel leak somewhere between the fuel pump and the carburetor. I had excessive fuel consumption on my Cuyuna and it turned out to be a pinhole leak in the fuel line right where it clamped to the carburetor inlet. It was hard to find because it only leaked when the engine was running, of course, and was swept away by the breeze from the propeller. I eventually found it by squeezing the fuel line when the engine wasn't running.

Dana

Beware of strange faces and dark dingy places, be careful while bending the law...
 

nickjaxe

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Joined
Aug 14, 2009
Messages
159
Location
England
Rminds me of a 2 stroke outboard motor I had some years ago...always ran fine till one day it would only run at higher RPM and used lots of fuel in the process,

Scratched my head with that one...convinced it was a carb prob...turned out to be the impluse fuel pump...it had a hole in the diaphragm and it was sucking neat fuel direct into the engine...by-passing the carbs....the motor could only handle the excess fuel at high RPM.

Nick.
 

King Chicken

Active Member
Joined
May 20, 2013
Messages
38
Location
Oak Grove, SC
Cruising around 5500 or so, plugs look good and are new
got to thinking and I was playing some as well, diving and climbing
Dana I'm thinking like you, just can't find the leak
going to tear it down and find out what is inside carb
Thanks for the suggestions. I do appreciate it.
I am a Private Pilot and I fly an older Phantom, and have about 400 hrs in Ultralights.
Thanks again for your suggestions.
 

ALEX MX

New Member
Joined
Dec 6, 2012
Messages
4
Location
Fort Lauderdale
Hello everyone! Friend of mine has QU MXL rotax 447, single CDI. CDI is broken and we are looking for used one or same ROTAX 447 with warranty...Any suggestions, please...
 

buzzypeterson

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Joined
Sep 23, 2010
Messages
160
Location
Wausau, WI USA
We had a boat with a 2 stroke that had a fuel burn that all of a sudden went crazy... we were fueling it up every other day.... Thought there was something seriously wrong with our motor... but then we noticed the neighbors car smoking and put two and two together.
 

corbinstein0

Member
Joined
Jan 17, 2011
Messages
14
Location
Almost Middle Tennessee
Fought the same thing on my mower last year...... eventually after a carb rebuild, new fuel pump, etc, I started feeding it gas by hand, just pouring it down the carb.... Ran fine....... figured out that a neighbor was swapping my gas for water! Now they're walkin.....

We had a boat with a 2 stroke that had a fuel burn that all of a sudden went crazy... we were fueling it up every other day.... Thought there was something seriously wrong with our motor... but then we noticed the neighbors car smoking and put two and two together.
 

phantomflyer90

New Member
Joined
Jul 31, 2013
Messages
1
Location
Mocksville
I own a older Phantom x-1 with a 447. It burns real close to 5 gal n hour. Thought this seems pretty steep.. What you guys think? Also, Guy I bought it off of told me not to run it over 6000 RPM for more than 2 min. Full power takeoff runs about 7000-7500 RPM... That sound about right? Just looking for the red zones on this engine.
 

nickjaxe

Well-Known Member
Joined
Aug 14, 2009
Messages
159
Location
England
7000-7500rpm thats way over what it should be...6500rpm max as far as I know....maybe your prop pitch is to fine...this could be why its burning so much fuel,

Have you checked your tach for accuracy???

Nick.
 
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