582 low on power

[dynomike 91]

since my avid is flying well I decided to repower my other little floatplane with a 582 to replace the 503.i bought a used grey head off barnstormers and installed it ,put the prop on it(off 503,warp drive )and it will only pull 3500 rpm . I dropped the pitch to 7.5 and will still only pull 5000.i checked timing today and was right on .compression is 105 -110 hot. egt 850.I am not a mechanic and need a little help deciding what to check next.it starts fine and idles .jets aren't plugged .engine is really low on power. thanx in advance for your time

 

 

both 503 and 582  b.box 2.58-1

Edited 7 Apr 2014 by dynomike

[lostman 198]

That sure doesn't sound right. Wish I could help you with that one. I have no idea what kind of compression those little engines are typically producing.

[dynomike 91]

i never did manually check the box ratio.it says 258 on it but i guess there is no guarantee that's whats in there.ill check gear ratio this morning

[Deejayel 1]

Mechanical or tinytach?

[akflyer 1427]

EGTS at 850 and hardly any prop pitch.  Either your not getting WOT or you running REALLY rich OR the oil cable is not adjusted right.  What main jets are you running, how do the plugs look after a WOT run and is your oil injection marks lining up at idle?

 

The tach question is a really good one also.  If its an analog tach then it would be WAY off, but running the prop that flat, your EGTS should be climbing through the roof.  It sounds like it is either really rich or the rotary valve is not timed right. 

 

100 is a bit low.  It should be around 125-130, but even at 100-110, it should be pulling more RPM than that.

 

[wolves200 31]

hmm.... Leny is right! but this question have many places to look....

 

if timing and compression is done, I should look in.

 

1.- Propeller pitch (this one is a tricky, if you don´t get it right your EGT and carb will never be right)

2.- Carburetor Jettings.

3.- Gearbox Oil, you can also take the plugs out and turn it by hand, and feel it.

4.- Spark plugs.

 

WOT; 5000 and up is controlled by the main JET.....

 

EAA hints for homebuilders has a good video on this....

 

http://www.eaavideo.org/video.aspx?v=2073201298001

 

browse for all the videos Brian Carpenter from Rainbow aviation there, explains precisely what you need to look.

[wolves200 31]

by the way, if you have a mechanical tacho and for any reason I cannot understand, don´t want to change to Tinytach or any other electronic RPM,

 

you can counter check your RPM with this tool here, only few bucks, ........should not be read under fluorescent light.......

 

http://www.hobbyking.com/hobbyking/store/__10783__Turnigy_Multi_Blade_Micro_Tachometer.html

[dynomike 91]

thanx for all the replies ,ive been haunted by this thing for two weeks.turned out it was 2.0-1 gears in a 2.58-1 box .I was almost going to tear it down out of frustration. glad to have figured it out anyway . thanx again for the assistance ,I hate to ask for help but that one had me stumped.

[EDMO 1078]

Mike,

      Please explain what this means - You were taking the engine rpms - not prop rpms - shouldn't you still turn 6500 or something like that, even if the prop had to have less pitch?   Did you have too much pitch to let the engine wind up?

 Sounds like you could get a prop overspeed at the  2.0 ratio too if you come up to full engine rpms?

EDMO

Edited 8 Apr 2014 by Ed In Missouri

[dynomike 91]

exactly ed, it would have oversped the prop.i happen to have an abox on an old 277 that has a 2.58 gearset . I pulled those today and ill put em in tomorrow. maybe get it in the air by this weekend.

[EDMO 1078]

I know that with my 1.84:1 ratio I cant turn the engine rpms that some of the 2.2:1 Stratus Soobs turn without overspeeding the 70 or 72 inch Warp Drive prop - I will still turn more than the 2500 rpms that Whirlwind limits its blades to - so got to stay with WD or IVO.  Glad you found the problem and can fix it.

EDMO

Edited 8 Apr 2014 by Ed In Missouri

[akflyer 1427]

well that will load it down for sure and explain the low EGTs!  I like gremlins that you can actually find and KNOW what it was that fixed the problem.

 

[dholly 718]

Good on you, I think it would have taken me a while to figure that one out.

[dynomike 91]

put the gears in it today and it runs perfect, 6500 at 12 degrees pitch. ill be on the water this weekend.it should perform a lot better with extra 13hp.

[EDMO 1078]

Good - Hope you have a nice flight.

EDMO