Prop Problems

[Mendlerr 4]

the airplane has a NavMan 2100 installed with low fuel and fuel flow emergency warning lights along with an alarm that triggers when my wing tank is 1 gallon from empty so I can turn on the fuel pump for the header tanks.  It seems to be fairly accurate so far except on right taxi turns at idle, it shoots up to 8gph fuel burn, lol. 

 

all I have done is remove the regulator and let the fuel run from the fuel pump line.  Alot of fuel comes out of that 1/4" line in a very short amount of time, haha

Edited 3 Jun 2013 by RMendler

[Av8r_Sed 82]

Re-reading your post about removing the FPR and noting a change in engine operation and fuel flow increase with the boost pump on would lead me to believe the boost pump puts out too high a pressure and is overwhelming the float valves. The FPR is necessary with this particular pump. A simpler solution would have been to use a lower pressue pump.

Other than a little added complexity and weight, what you've got should work fine. Just use the boost pump as Leni described you should have no problem.

[Mendlerr 4]

Finally got my freakin jets in today.

 

I installed the 165 main jet and a 45 idle jet.  holy crap what a difference.

 

the engine idles smooth down to 2,500 (was 3,100RPM idle before)

 

the top end holds hard at 6,200RPM static and 1,100f EGT's with good cylinder temps.

 

Had to do some poor man's syncing on the carbs but I think I have them very close.  Next we need to fly it, the weather was awful today.

[akflyer 1427]

Sounds like you still need to tweak the idle air mixture.  You should get a good idle at around 2000.  At 2500 your gonna float for awhile on landings unless you really set up the approach attitude right.  I love my clutch, I can idle it at 1450-1500 all day long and no shake to the engine, but then again, its not turning the prop

[Mendlerr 4]

as soon as my trailer sells a clutch will be on the way.  I don't think the prop is balanced enough to spin any lower, it starts to vibrate pretty good at lower rpms.  <2,600

[C5Engineer 1170]

It's probably not your prop its your engine running too rich! Lean out the air screws and put Ina smaller idler jet. I am 5 smaller on my idler than the Rotax jetting chart shows. Your not gonna burn her up at idle. I've seen this on a ton of 2-stroke powered planes. If your prop is so put of balance that it shakes the plane at idle then it would tear the motor off the front at full power.

[C5Engineer 1170]

Whoops missed that you had already re jetted the first time.

[Mendlerr 4]

the airplane runs smooth at 6,200-6,600.  It does not run smooth below 2,600 or so.  I was told that this is probably caused by the wood prop.  I had our local A&P take a look at the prop yesterday, he thought everything looked good, including the space in between the spacer blocks.  Might be the size of the prop causing it not to idle any lower.  Too much prop for that little engine

 

I may also try backing off the idle mixture screw just a little.  What do you guys feel is a safe EGT at idle?

Edited 9 Jun 2013 by RMendler

[akflyer 1427]

mine at idle does not even register on the gauge..

 

[C5Engineer 1170]

X2. If your making the correct static RPM it shouldn't be too much prop for idle. With my IFA even at full course pitch it only slowed the idle down about 200rpm or so.

[Mendlerr 4]

Guess I'll try leaning it out some more and adjusting the idle.  My idle EGT's are 1,000 degrees.  I hate for them to go too much higher but I suppose the engine is not under load at that point anyways

[akflyer 1427]

damn, I have to crank mine up to about 3000-3500 before they even hit 800. 

 

How have you been synchronizing your carbs?  I am wondering if they are out of sync and that is contributing to the rough idle.  What is your mag drop?

 

[Mendlerr 4]

poor mans way.

 

I took the K&N filter off and opened the throttle up fully, I then align the two pistons in the carb exactly using marks on the pistons and walls.

 

I then ensure that they both begin opening and closing at the same time, I also make sure that they move in unisen.

 

I adjust the idle air screws so they are even against the pistons.

 

I start the engine and let it warm, i check the EGT difference between the 2 cylinders and and adjust the idle screw until they are equal.

 

Seems to work well enough, atleast until I can afford a CarbMate

[akflyer 1427]

The idle air screws dont hit the pistons, that is the idle stop screw.  The idle air screw is the smaller one that changes the idle air mixture.  The poor boy method gets you pretty damn close, but I do like the carb mate for final ajustments.  If you would like, I can box mine up and mail it to you if your problems persist or if you just want it to do a check on your set up!

 

[C5Engineer 1170]

The way you did yours is all I've ever done to mine. I have my idle set at about 2200...at 2000 it'll start to run a bit rough. If I am at a high density altitude a couple turns of the Hacman smooths it right up. Here's a link I found regarding your issue that might help.

 

http://www.rotax-owner.com/rotax-blog/item/2-roughness-2

 

On the airscrews the further out they are means more air and less gas (leaner) and turning them in is the opposite (rich) If you find they are are backed way out and your still running rich you need a smaller idler jet.

[Mendlerr 4]

I just replaced the the OEM 55 idle jet with a 45 idle jet.  My idle EGT's went from 800ish to 950-1000.  I don't think I am running too rich at idle.  With the throttle pulled all the way to idle the RPM's will only drop to 2,600 or so.  The idle stop screw doesn't seemt to make a difference anymore

 

I'm still playing with it though.  I'll do some more tweaking in the next few days

Edited 10 Jun 2013 by RMendler

[Mendlerr 4]

I ordered my UL 72" IVO IFA and the RK400 clutch.  Should have the parts in about 2 weeks.  I'm excited.  I hope it makes a big difference over the GSC and I'm really excited about this clutch.

[SuberAvid 617]

I ordered my UL 72" IVO IFA and the RK400 clutch.  Should have the parts in about 2 weeks.  I'm excited.  I hope it makes a big difference over the GSC and I'm really excited about this clutch.

Sorry I missed answering you about my prop; mine is a 72" 3 blade medium on a Subaru but if your running the 582, the UL should be the correct prop and a lot cheaper.  Joey, Leni and Chris all have experience with them and you will find quite a bit of good info in some past threads on here in getting them set up.  The UL prop has two different blades available with different relaxed pitch rates so it would be good to confirm the pitch rate they have found to be best so you don't burn out your drive motor too frequently.

[Mendlerr 4]

I asked IVO about the prop pitch and they told me the standard pitch works much better then the hi pitch so thats what i ordered.

[horsepower 24]

I just replaced the the OEM 55 idle jet with a 45 idle jet.  My idle EGT's went from 800ish to 950-1000.  I don't think I am running too rich at idle.  With the throttle pulled all the way to idle the RPM's will only drop to 2,600 or so.  The idle stop screw doesn't seemt to make a difference anymore

 

I'm still playing with it though.  I'll do some more tweaking in the next few days

You probably need to adjust your cable to let the slide drop deeper into your jet.I adjusted my cable to idle at 1800 and then turned up the idle screws to get my 2000 idle rpm so slide is not hanging off of cables at an idle.Make sure and sync them the same.Randy

[Mendlerr 4]

You probably need to adjust your cable to let the slide drop deeper into your jet.I adjusted my cable to idle at 1800 and then turned up the idle screws to get my 2000 idle rpm so slide is not hanging off of cables at an idle.Make sure and sync them the same.Randy

Where I have the cables set at now show about 3 threads on the top of the carb.  It won't allow the piston to drop completely, you are correct.  If I try to adjust the cables down anymore the piston will not move up far enough to clear the intake cylinder completely.

 

I'm going to check the cables, they don't seem to have any sticking issues but I'm going to double check them.  Perhaps that are too short?

Edited 14 Jun 2013 by RMendler

[C5Engineer 1170]

That's a possibility! Be careful when you reassemble the top of a Bing 54. The cable does not go down the center the needle does. I put one in 180 degrees off one time and almost found the hard way. I happened to take it apart while up in Idaho to adjust my needles for the high altitude and my throttle cable only had about 3 strands left holding it together. I would of wound up in the trees had it snapped when I dropped a cylinder. The Bing 64 on the 912 is spring loaded open...a much better design IMO.

[Mendlerr 4]

I took the carbs off today along with the entire throttle system with our local A&P Rotax 2-Stroke expert and he immediately noticed the problem.  For starters the 2 throttle cables are 2 different lengths and the longest cable is still 1/2" short.  They look like some rigged up Suzuki clutch cables with the fittings soldered on the end, definitely rigged by the previous owner.

 

We are going to fly tomorrow because it does not affect top end performance and we need to check a few things but once we land we are going to make some new cables and see if we can't get the idle down to 2,000 or a little lower.  we will also be installing the clutch that showed up today..

Edited 14 Jun 2013 by RMendler

[C5Engineer 1170]

Fun stuff! I had mine made at a small engine repair shop that specialized in lawn mowers. He used my old ones as a pattern and went from there.

[Mendlerr 4]

Fun stuff! I had mine made at a small engine repair shop that specialized in lawn mowers. He used my old ones as a pattern and went from there.

I just dropped the cables of at the local A&P's shop, he's going to use the longest one and then add 3/8 to 1/2 an inch on the new cables.  One of them was about 4 inches shorter then the other and travel was really limited

 

We got the plane in the air today for 1.6 hours.  Other then poor climb performance we did get off the ground without any serious doubt of safety.

 

I think this new IVO prop will help out tremendously with the climb issues.

 

Next wednesday the clutch and the new throttle cables are being installed. 

Edited 15 Jun 2013 by RMendler