582 Power Issue??

[robotguy]

582 Total rebuild at 194.0hrs in 2004 by Solo Aviation for plane sale i guess. Long story short after short runs over a long time I bought it with 279 hrs. run great until 11/1/2015 at 319hrs 4 min run up, mag test fine full power 6250rpm (prop pitched for speed). 100 ft down runway power falls to 5000rpm. Cold morning maybe ice so taxi back, hold brakes and power up 6200 and holds while dragging locked wheels about 25 ft over 30ish seconds. So launch again, same thing, go out and fly kinda committed out of runway. In the sky I can maintain 5600rpm. So back to hanger, Change plugs (hrs unknown) Check floats on carbs, (fine). Check all my automotive gas lines after gas collator, their fine. Gas collator bowl fine no debris. So rebuild fuel pump just in case. Oh yea now check screen in gas collator, covered with a clear film that has abstructed the screen. Ah hah, clean put all back together, tie plane off start and 6250 for 4 mins, wow was that scary. Out to runway, launch now only falls off to 5600 rpms. Every time on take off but not tied off. So thats why I'm at a loss. Why the power drop on roll out? In the sky level flight it will maintain 6000 rpms but don't know for how long as that exceeds the vne of 100mph for the plane (kitfox 2). Any body else ever run into this with the 582 Grey Head.

[tx_swordguy]

when you shut it off after its warm do a mag check before you shut down. It could be a bad pickup coil. I had a similar problem on a gyro with a 582. I noticed a fluctuating rpm in the air and it would shut off (when I was shutting down)on only one mag after it was hot. What was happening was the pickup coil was not totally crapping out. cold it would work but once it was hot the electronics would break down and not work right. Therefore I was only getting rpms off one side and occasionally the other and that was why I was getting fluctuating rpms. You can ohm the pickup coils without taking them out. I don't remember for sure the numbers but I think the old style in the 80-90 range and new style in the 140ish range. (search testing rotax pickup coils)
Mark

[birddog486]

The foreign material on the screen was telling you there may be a fuel issue causing your problem. Is there another fuel filter in the system?

Has car gas been used in the tanks? Ethanol dissolving some of the resin in the tanks?

[Av8r_Sed]

Are you running a thermostat? Is your water temp at least 150 deg before applying full power?

[TY2068]

I'm curious as to the type and brand of 2-stroke oil you are using. Are you pre-mixing or using oil injection ? Ethanol or Non-E gas, what octane ? Dual filters (auto type canister with paper media or different type with metal screen) on the lines after the fuel pump.

[avidflyer]

I think birddog is on to something. I would double check all gas lines, filters, and do some fuel flow testing. What are your EGTs doing when the power drops off? If you are going lean, EGTs should go up. Try putting on the enrichers/chokes when the power drops off. If rpm goes down it's not to lean, if rpm goes up it's to lean. Jim Chuk

[robotguy]

My thermostat has always run about 145, and the gas collator is the only filter on the system. As far as the mag test its always good. My egts have always gone pretty high when i cut back on power 1275 and 1250. Haven't really looked on take off during the power drop. I've been trying to run co op's non ethonal 91 octane gas, but do occasionally get stuck with shells 93 octane (ethonal). It's the tie off with the 4 min run at 6200 that is confussing me. Whats different between that and rolling down the runway? I am thinking about installing a electric fuel pump for take offs to see if that helps. As far as the 2 cycle oil, it is injected and I use the same as previous owners AV-2 Black gallon jug with blue lable. Had issues with injection when first got plane but that was too much oil dripping out of filter when parked. Annual found kinked cable under dash wasn't letting the oil injector shut off or the throttle, thats why I had a high idle 3000rpm. Thats all been fixed. There was a couple times while working on the injector issue I added oil to gas to make sure I was getting enough..

[birddog486]

Running ethanol gas in those tanks can soften and cause the resin to slowly dissolve and buildup in the fuel screen in the tank, the lines, filters and carbs, eventually causing the fuel to stop flowing fast enough to feed the engine.

If it was me, First thing would be to plug the header tank vent and pull the fuel line as it enters the fuel pump to check the flow. If your able do one tank at a time.

[Dusty]

You have checked the floats,I assume you checked the float level.
Fuel tap off ,remove the bowls,are they the same and rotax setting height?
EGT's when the power drops will tell you a lot,
Good EGT and power on the ground and in the air but low on rollout(especially a rough strip)would make me want to be sure of the float level,also have a look at the vent tubes,although unlikely are easy to check

[TY2068]

I think the best clue you have provided is the residue found on the gascolater screen. What that is and where it's coming from needs to be investigated. Sound like a fuel restriction-starvation-delivery issue.

In the past I've had fuel-oil seperation problems when using E-fuel pre-mix that sat for a few weeks. I have found carb inlet screens (smaller Rotax engines) choked with a sticky clear film. Using Non-E fuel and API-TC rated oil solved the problem completely. I've had no Tank resin problems on my Kitfox but you should look at that possibilty carefully. I will not use E-fuel in my Kitfox or Ultralight.

The guys with more experience can chime in here but my understanding is that there should be in-line filters after the fuel pump on the carb supply lines. My Kitfox was purchased having small auto-tractor type cannister paper media filters on those lines. I opted to use stainless screen media Golan peak flow mini filters there instead.

I personally would not fly the plane again until the problem is found.

[nlappos]

Just a clue on the cutback while taking off but not on a static thrust check: The takeoff has a sporty acceleration that throws the fuel back against all surfaces (tanks, filters, fuel lines, header tank) so there could be some readjustment of the stuff that forms the blockage that wasn't seen statically. An acceleration of about .2 Gs (4 knots per second) will "look" like a 12 degree upslope to the fuel system.

[dynomike]

and maybe ram air pressure .fuel issues can be a pain to figure out

[robotguy]

Thanks for the ideas guys, I'm gonna dump the tanks this weekend filter it as i do to see if i get anymore residue. Plan on replacing all rubber hoses after the aluminum line that goes from header tank to the gas collator, l replaced that last year. Will probably remove gas collator and go with regular see through filters. Gonna recheck the floats on the carbs also. Due the measurement on gas level in bowl to verify. Will keep all posted on results..

[Olle1975]

Anything new about your power issue?

Olaf

[robotguy]

Hey Olaf, and others.
I did drain the tanks and filter through a coffee filter as I did, all was clean. I did notice a very bright reflection from inside the tanks when I looked inside them, they appear to be metal?? I verified the floats on the carbs they were good. Also noticed that when I filled tanks back up real good flow all the way up to the manual pump. Couple throws with the prop and bowls full again. Went out for a test flight, rpms only dropped to 5700 on take off. Climbed to 1000' AGL, 1800MSL leveled off and flew to a friends house maintain 6000 rpms all the way. Set down in the field at his house, on my departure there I actually maintained 5900rpms on take off and climb out at 500fpm, no steeper do to bumps in the tabulate air. Here's the fun part, headed due east to my brothers house 30miles away, with a tail wind and 6000 rpms I set right on the 100mph vne, ground speed was 115. Set down at his house, and yep you guessed it, 2 cycle again 5600 max rpm on departure till leveled off then right back up to 6000rpms??? So now I have removed the gascolator, and the primer (never use it anyway) and replaced it with the see through filter, changed all the gas lines from the shutoff valve in the cockpit to the engine. Am presently waiting for time off and decent weather to test. Oh yea I did ohm everything electrical (wires,caps,coils,mags), all checked good measuring right on the specs..

[JimS]

Something else to check. I had a similar issue that I could reproduce. Level flight ..OK. Nose up to climb at full power and engine would go lean and sag. Long story short, what I found was the hose that comes off the crankcase to pulse the fuel pump had over time been restricted down to about half its I.D. The nipple on the crankcase is not that long, and at every condition inspection we all check/tweek all the hose clamps to make sure they are tight , right? Well after about 6 years of tweeking the hoseclamp (which hung just oveer the end of the crankcase nipple) restricted the pulse line enough that there was enough fuel for level flight but not for a full power climb. Thank God and Greyhound that I had an electric pump to turn on which made the motor go loud again. Of course I checked all fuel lines, filters, carbs etc. but when I finally found this, it was obviously the culprit.

[robotguy]

Finally got a day off and decent weather to test latest fixes on power loss. Gascolator removed, replaced with inline filter. Primer removed with gascolator, didn't use anyway. New 1/4" hose from cockpit shutoff to pump. also replaced supply from engine crankcase to pump. Set so long it was a little sluggish starting, (25° outside). 5 min. warm up full power take off dropped to 5500rpm till leveled off right back up to 6300rpm. So I guess only thing left to check now is the rebuilt carbs? I did notice that as cold as it was when I backed power off to 5000rpm for cruise 1 egt went to 1350 other stayed at 1175-1200. They run at 1050 to 1150 under power, and drop way off to 900ish power backed off for landing. So at this point whats thoughts on electric pump backup! Hasn't needed one up till now but?? Still flying solo I've practiced take offs enough that 5000 rpm will get me off the ground at about 200' a min. climb and I don't need power to land, so till the crops go back in the whole country side around me is a runway.

Eugene.

[WISDAN]

Eugene, have you checked the carb. jets to see if not plugged or loose?
We had a 912 with a loose main jet land at our local airport after a major power loss.
Just thought might be another item to check.

[tx_swordguy]

An electric fuel pump is a cheap experiment and could not hurt to try. It is not very time consuming to put in place and see if it makes a difference. If you replace the filters with see thru make sure they are large enough to allow flow even when slightly blocked (stay away from paper if you can, water can make the paper swell and stop flow). the small ones with the brass filtering media work great until they get plugged and stop flow (doesn't take much). Clean the carbs again even if you already did (take jets out and clean individually not just open and spray bottom of carb). Main jet is rather large but may have some old gas varnish stuck on inside causing flow issues. That one egt is high, I would drop the clip on the needle (raising the needle in the carb slide. I know supposedly the needle is not effective at that throttle range according to the book (trust me, it is). Looking back at your post under full power 1175 is a bit high (for me). I get my cruise egts in the 1125-1150 and my full throttle at about 1050. Your main jet comes in to play at full throttle and your needle will be effective all the way up to 6000 rpms . I know others will disagree about how high the needle is effective and that is fine. I know this from working on my own 582 so take it or leave it. This assumes you want 6500 max straight and level with a cruise in the 5800-6000 range.

[avidflyer]

Don't know if it was mentioned or not, and you really shouldn't need them normally, but do you have the ram air tubes in your gas caps on your wing tanks? They pressurize the tanks a bit and help fuel flow while in flight. Jim Chuk

[Dusty]

One egt higher?
If you don't have a fuel blockage the carb vent tubes would be my next easy item to eliminate as a possible cause.

[Olle1975]

Hi!

I think you have a problem with your pneumatic fuelpump, I would measure the fuelpressure between fuelpump and carbs.
There you need 0,2 - 0,5 bar pressure during all rpm's. May be, you only need a rebuildkit for your Mikuni-Fuelpump or it's only dirty inside.
Remove the bolts and make sure nothing dirt inside.

KLICK (https://www.youtube.com/watch?v=Z0LRwwmkkUM)

If you haven't got these pressures, change (or rebuild) it or install a new one or install a electric pump like swordguy said.
You have to ensure enough fuelpressure.

Olaf

[robotguy]

Just thought i'd let all know, i think i'm onto the lost rpm's issue. Problem kinda told on itself. With everything replaced involved in fuel supply from tanks to engine, and no results, I continued flying as I had enough rpms to solo. But noticed that my idle kept getting worse to the point of anything under 4000 rpms was shaking the airplane apart, (yes that bad). Makes for a tuff time landing worrying about engine dying. The carbs had been removed twice and gone through with nothing abnormal found. So decided to tie the plane off and try adjusting the idle jets (not the one the holds the barrel up). Got it tweeked to a smooth idle all the way down to 1900ish. Have had 7 take offs now with 6000 rpms and back to my 1000fmp climb out. No longer using installed electric back up fuel pump other than to prime the bowls to start the plane. :)

[Olle1975]

Hello!

I can't understand, may be I have translation problems but you can't adjust the idle jet, you could change it but no adjusting!?
May be you adjust the airscrew for idle but it can't been your problem.
What was the problem in your opinion?

Olaf

[robotguy]

Yea sorry I meant the air mixture jet. I think the original problem was that film I had on the Gascolator screen. But some where in the mix of replacing everything and cleaning the carbs those air mixture jets got out of sink enough to mess with max rpm ?? Like I mentioned the idle on power cut back for landing kept getting worse till I finally adjusted those air mixture jets to a smooth idle down to 1900rpm. Now the bad shaking is gone and my rpms are back. Time will tell if it lasts. Everything I had replaced, even the electric pump I installed for take offs, the cleaning of the carbs, nothing got my rpms back until I adjusted those air mixture jets? Can't explain it but man am I glad it worked, love having my short takeoff and 1000fpm climb out back.

[nsudduth]

I was having a loss of power issue and thought it was a fuel flow problem.
After a lot of testing the fuel system I changed the spark plugs(at the suggestion of Rotax Rick) and it fixed
the problem.:)

[robotguy]

Yea you won't believe this but Rotax Rick can verify, after a year and a half of fighting with that issue, everything had been changed with no help. So I bought a new engine off Rotax Rick, 670, had the exhaust modified for the engine, even went with a brand new warp drive prop. Guess what, SAME PROBLEM! Under pitched the prop to 6800 static, so it would only drop off to 6300 to 6400 on roll out. Even the airplane mechanics locally are baffled. At least this 670 will climb out at 1100fpm, but i can only get about 85mph cruise cause the prop is under pitched. I am currently trying to find a IV or V so i can go to the 4 stroke.