Rotax 532 help please

[bryancobb]

That tiny detail is soooo important if you are using a diaphragm-type fuel pump. Not using the right pulse line is like using a piece of heater-hose as the pump lever on one of these.

The carb works just like a bathroom commode, and we all know how poor of a job a HALF-FULL commode tank does at making the poop go down...OR KEEPING A THIRSTY 2-STROKE SUPPLIED WITH LIFE-SUSTAINING LIQUID.

 

[scottessex]

Good point! Never use fuel line, Pulse line is much thicker walled. If you must use an automotive product make sure that you use vacuum line so it does not collapse under negative pressure pulses.

 

[SandL]

flew for 1 hour today

did half an hour over the airfield , climbed to 2,000 ft great weather all ok
landed checked things were ok then off again
climbed up to 2,000 then left the airfield to fly over another disused airfield , messed about defined that I can maintain height at 6,200 at 55 mph with my new prop, decended to 1,000 climbed back up and headed about 5 miles back to home base over lots of open country with cut fields below ... then out of the blue the engine developed the same problem , RPM dies to about 4,000 , I came back on throttle and lookd at field , then opened up again and the power came back to 6,800rpm headed to home base climbing all the time up to about 1,800 then as I became over head the RPM dropped to 3,000 and no matter what I did with the throttle it would not get over 4,000
, landed and gave myself a long taxi back. opened throttle and could not get RPM over 4,000. killed ignition and dismounted ... filters were clean and full pulse pipe was warm. float chamber on the rear carb appeared to have a small leak outside of float bowel was wet with fuel and sticky with 2 stroke oil so I guess there was a leak but prop was not smeared so a small leak maybe I will check the gasket is seating properly on my next visit.
(I have a new stiff pulse pipe on order, the one I installed was a fuel pipe, possible it got warm and flexed too much.)
so it ran perfectly for about an hour, makes you think there is a fuel blockage in the tank , but it has 2 tanks with 2 fuel supply outlets. running through a clear, clean gascolator. and filter before the pump. 1 filter after the pump was full of fuel and the other 80% full.
back to drawing board
will change pulse pipe again then what ... ground run at full power for an hour ! ?
after next flight test, if it fails I will land and tie down quickly then try to reproduce the problem with a warm engine and a solid fault spraying WD40 and applying choke etc
will let you know how I get on..

anyone want to buy a 532 ? !!

 

[scottessex]

I would change the pulse line, and change the fuel pump. If your pump is over 2 years old it should be changed, just for piece of mind, I have had the mikuni pumps act the exact same way, that is why I have an electric pump also.

 

[SandL]

I have bought an electric pump and know how and where to fit it so after the correct pulse pipe arrives I will test fly and then ... electric pump and if I can get a solid fault with me on the ground standing next to it I will be able to apply choke and spray wd40 on the carb mounts etc. but I need a solid fault
the fact it want away and came back suggests that it maybe something I did on my last maint change , eg the pulse pipe (ordered the pipe and the supplier sent me a carb heater kit by mistake so it's back and forth with the post right now.)

 

[wolves200]

Hello Sand;

I have a 532 with same situation as you, and will tell you one thing, "PROPELLER"

borrow a propeller from a friend, and make a test; but it has to be a fixed prop, 2 blades specifically for this engine and gear box, my case i didn´t have any friend at all so I bought a cheappy prop from Romania; worked like a charm, my engine simply doesn´t like the GSC prop, I discovered other problems though and learn alot in the process.

hope it helps
Regards
Dimi3

 

[scandtours]

I will post little bit later today a copy of what Rotax factory says about this problem. They were aware of this problem for years ago.
This was one of reasons why they developed the 582 engine.

 

[scandtours]

Just few lines of what Rotax customers' Information from 1989 says (before I will find little time to scan it and post it.)

The water-cooled ultralight engine type 532 has been most popular over many years and is installed in numerous ultralights.
Due to its steep power and high peak performance the 532 occasionally causes uncomfortable speed instability at partial load between 4000 and 5000 rpm...........more to come as PDF file.
I wrote many times before to the factory and after a very long time came with
this inf.

 

[SandL]

at last an update
I have had a few family issues over the last few months (old folk and 2 local friends passing on) I have been tinkering and just when I think I have found the problem after an hours trouble free flying it comes back.
anyway the engine has been idle for about a month so I went to fire it up today and it now has a solid fault on the rear cylinder, I placed a light up spark cap on each and the rear did not light up so I now have a clearly identified rear cylinder, spark, HT lead, earth, plug cap, coil problem. a nice solid fault at last. one of the first things I did was swap the coils some months ago, maybe I had a bad one. anyway I am off to Vietnam & Cambodia and will fit new upon my return ... at last .... I hope

 

[dinoa]

It is not unusual to loose a coil. I had a failure about every 130hrs in my 532. The first time it just dropped engine rpm to about 4000 rpm, the second and third time it would start to miss getting progressively worse about 5 hrs before replacing.

When I first got the engine in 1990, I asked Phil Lockwood what spares to keep in stock. He promptly sold me a set of coils.

Dino

 

[SandL]

Took the gyro to a rotax specialist , he removed the engine and found a failed condenser near the points , replaced, fixed... engine runneing perfectly . reinstalled and trail back to Draycott at last ... now to get the blades on and a shake down all ready for the summer. with a bit of luck.

 

[scottessex]

Good you found the problem.

 

[SandL]

You will not believe this !

When I had the engine fixed I asked the guy to change the rubber fuel pipe as it cracks over time and it’s so much easier to do whilst the engine is out
Well you may have read in the LAA news that Semprit produced a bad batch of fuel pipe that perishes with fuel internally over a short period of time, (they missed an additive out of the manufacturing process) so have issued a recall
And after checking I find mine now has the bad batch of pipe installed

I just don’t believe the luck.
Anyway the only consolation is “ better to be on the ground wishing I was in the air than in the air wishing I was on the ground “