Rotax 582 looses power

[nsudduth]

I have a Kitfox model IV with a 582 engine. It looses about a thousand rpm's
when taking off. After I apply full power rpm's come up to 6000 to 6400 as
soon aircraft starts moving foward rpm's drop to 5000.

I have checked compression good on both cyl. (120lb). checked carburetors.
Replaced all fuel lines. rebuilt pulse fuel pump. Same condition with electric fuel pump on or off.

Any advice would be appreciated.

Norton Sudduth

[TY2068]

Sounds like same problem reported a while back.

http://www.teamkitfox.com/Forums/showthread.php?t=6911&page=3

[nsudduth]

Sounds like same problem reported a while back.

http://www.teamkitfox.com/Forums/showthread.php?t=6911&page=3
What is a safe way to adjust the air mixture with the engine running?

[nsudduth]

What is a safe way to adjust the air mixture with the engine running?

I have checked the air screw adjustment. it is set correct. i have rechecked all jets in carbs. everything checks ok. i can't find a problem with carbs. still loosing 1000 rpms when start take off roll.

[avidflyer]

What prop are you running? Was it running fine before, and then this started happening by it's self, or did you do any adjusting or changes before this problem started to happen? JimChuk

[Guy Buchanan]

I had this happen when I increased prop pitch. My theory was that the prop stalls at zero airspeed, then hooks up when you start to move, but because of the pitch bogs the motor. We're talking 1/2 degree of prop pitch did it. I was using a 68" three blade Warp taper.

[TY2068]

I'm new to the Kitfox and 582's so I've taken a keen interest in learning why a problem like this can occur. What I've discovered is this problem (mysterious RPM decrease upon take-off roll) apparently manifests itself the same exact way but reportedly can happen for totally different reasons. One guy finds it's a prop problem, another finds out it's a faulty tachometer, yet another discovers some electrical issue with a coil, wire, plug or pick-up. Others report a good carb cleaning, rebuild or slight adjustment killed their Gremlin. One fellow reported a cable slack-adjustment issue to be the culprit. I thought I might even read where it happened to one guy on Tuesdays so he started flying on Wednesday.

From my research I've come to this one solid conclusion. If it happens to me I'm going to scream loudly OH CRAP among other things !!!

Be sure to let us know what you find.

[Monocock]

I had the same situation as Guy Buchanan.

My IVO on my 582 was running fine, until I decided to add a bit more pitch one day when I had a long trip to do. There was an rpm drop on take off, enough to make me abort. I tried again and it did the same. I returned the pitch to what it was and it was then fine. I then added the pitch back and it did the same.

I got bored of fiddling so I just departed and did my trip.

[jrthomas]

One of my buddys had a similar problem with a 447. It was on the nose of a little plans built taildragger. After a good warmup he'd go full throttle and it would rev right up. I don't remember the static rpm but backoff and go full throttle the second time and it wouldn't go past about about 4000. Cut it off and let it sit a while, start it up and it would make good rpm. Back off and go full again and again it wouldn't go past about 4000. He's pretty experienced with Rotax engines and tried about everything and nothing worked. He had a spare 447 so he mounted it and fired it up. Guess what! Same result. It had a wood, fixed pitch prop that was supposed to be the correct pitch for a 447. For some reason it would rev up on the first rev but not after that. The only answer we could come up with was maybe the 447 lacked the torque to pull the prop through the midrange consistantly. Why it would rev up on the 1st pull but would not repeat is still a mystery. Anyway, a prop change took care of the problem. James Thomas

[Olle1975]

Any News?

Olaf

[nsudduth]

Any News?

Olaf

The problem with power loss was in the propeller pitch. It was set at 19 degrees. At first I changed it to 13 degrees and it would over rev. Finally change to 16.5 degrees and now it does a lot better. I still don't see the 1200 to 1500 ft. per min. climb the spec sheet says it should have. It's
more like 700 to 900 fpm.

[avidflyer]

Spec sheet was probably optimistic at best. and maybe with a super light plane and pilot with not much fuel on board. When did a manufacturer ever stretch the truth??? JImChuk

[TY2068]

What prop are you using ?

[nsudduth]

What prop are you using ?

It has a GSC 3 blade wood prop 68".

[nsudduth]

I'm new to the Kitfox and 582's so I've taken a keen interest in learning why a problem like this can occur. What I've discovered is this problem (mysterious RPM decrease upon take-off roll) apparently manifests itself the same exact way but reportedly can happen for totally different reasons. One guy finds it's a prop problem, another finds out it's a faulty tachometer, yet another discovers some electrical issue with a coil, wire, plug or pick-up. Others report a good carb cleaning, rebuild or slight adjustment killed their Gremlin. One fellow reported a cable slack-adjustment issue to be the culprit. I thought I might even read where it happened to one guy on Tuesdays so he started flying on Wednesday.

From my research I've come to this one solid conclusion. If it happens to me I'm going to scream loudly OH CRAP among other things !!!

Be sure to let us know what you find.

It was the prop not pitched correctly. Change from 19 degrees to 16.5
degrees. Now have good rpms 6200 climb out.

[TY2068]

Did the prop move on its own slightly over time or were you making some adjustments when the rpm drop problem surfaced ?

My Kitfox had a 68" GSC when I purchased it also. It was already past the expected service life and I just didn't like the looks of its condition. After some research and talking to a few guys I went with the ground adjust IVO 72" medium 2-blade. Easy adjust, smooth and great performance.

[jonstark]

Did the prop move on its own slightly over time or were you making some adjustments when the rpm drop problem surfaced ?

My Kitfox had a 68" GSC when I purchased it also. It was already past the expected service life and I just didn't like the looks of its condition. After some research and talking to a few guys I went with the ground adjust IVO 72" medium 2-blade. Easy adjust, smooth and great performance.

Is your plane 582 powered?
Which gear box?
Why not the light weight three blade IVO?

Jon

[TY2068]

Yes, 582 with C-Box 3:1. Ivo advised to not use the Ultralight 3-Blade on the 3:1 C because of some issue they discovered. I asked how many 2-Blade 70-72 mediums they had sold for Kitfox's and it was quite a few. So knowing none the better that's what I got. I wanted to try a P-tip as I have many hours behind them on other aircraft but didn't want the long wait for one. I'm happy with the prop so far. Really makes dialing in your desired static rpm a snap.