Fezz-RCU

Hi,

Great site! Am new to power (have been flying sailplanes/slope soaring for 20 years). Got my son a Hobbico Superstar for B-day and am having problems getting the O.S. 40 LA to start up. When we first fired it up, it turned over on the second flip. We have broken it in with two tanks running "rich". However, when I shut her down and then try to start her up again, it is many flips etc. before I get her to start. I try to start without priming and when it doesn't start, I go ahead and prime it but it is still a long task to get her to go. Sometimes the engine will turn for a second but it then will sputter. It almosts seems like it is building too much compression or something as it will stop in the middle of a stroke and be stuck while fully compressed. I'm using a saftey stick and the glow plug is glowing fine. Any ideas?

Also, I didn't realize that you were supposed to use "loc tite" on the prop nut so in the course of trying to start the engine, I had the "spinner" loosen up 3 times. I think it is now stripped (the little ridges on the back are gone). What is the purpose of the "spinner". Know this might be a stupid question. Can I just mount the wooden prop right onto the prop shaft?

Thanks for any help.

Fezz

specialk566

My Feedback: (3)

My la and some engines in general do not always start easily by hand when warm. Mine would start fine after letting it cool down a few minutes though. Keep running it rich, two tanks isnt exactly "broken in". Its flyable, but the first few flights keep it a little rich. (la engines seem to be perpetually rich, so this shouldnt be a big problem). Also the pinch test is a great way to tune the high end needle. Start the engine, run it up to full throttle, and quickly pinch the fuel line that connects the tank to the remote needle, (pinch and let go, do not hold) . If the engine speeds up its rich. If it sags its too lean (richen it up a few clicks and pinch again.) If it sounds the same it is ok, but richen the needle up a few clicks to compensate for the leaning out it will do as the fuel level drops. Idealy you want to pinch the line and hear it speed up slightly. After all that fly it.
Hope your la runs better than mine
good luck

ajvpb

My Feedback: (3)

Don't worry, mine did that too. For some more of the tanks, since the cylinder is tapered, it may do that. When it is not fully broken in the fit at TDC is extremely tight. My dad and I spent a whole day trying to get my la to start. Make sure you have the throttle at idle. I was trying to do it with 1/2-3/4 throttle, it doesn't work, take my word for it. Also, they will start harder when warm. Just keep going at it, make sure it is good and rich. Good luck

Alex

jaka

Hi!
First of all the OS LA engine is a ABN engine and such engines must be run-in at fairly high rpm....say at 8000-12000 rpm using a 10x6 prop.
Loctite on the treads....??! You most be joking!
You don't have to put anything on the treads!! Just tork the nut down firmly....and why use a wood prop ?? Get a APC Gray plastic instead ..it will perform much better than an old top-Flite or Zinger wood prop.
If you are a newcomer using the OS .40 in a high winged trainer I would definitely recommend a 11x6 APC prop as this prop will give you better flight performance...not perhaps higher speed or better trust....but better, calmer ,more relaxed flying behavior of your airplane.

Regards!
Jan K
Sweden

JimTrainor

I had one - exactly the same sort of problems.

It starts easily by hand when it is cool, but not when hot.

No problems with an electric starter when hot.

The solution: let it cool down before restarting by hand. Same as other suggested.

I ran a 10x6 APC on mine (same plane).... never tached it, but it pulled it around without problem. It idled a bit better with an APC prop due the increased weight (inertia) of the prop.

I had the spinner "spin off" a few times as well. Early on, it was because I was trying to start engine when it was flooded. The piston would not go through compression (hydraulic lock) and the result is that you end up unwinding the prop. Once I got the the hang it.. no problem.

As for the little ridges, just score the back lightly with a knife to create some new ridge.... yup, I did that too.

Fezz-RCU

Thanks for all of the posts on my beginner starting engine blues. I think I was flooding it or going too rich which must be why I was backing the prop nut off (hydraulock?). I primed less today, and kept the carb a little more closed and that seemed to do the trick.

Also got first flight in today. A little tough for me as I have always flown sailplanes with two sticks set up with left being elevator and right ailerons or rudder. I had to keep reminding myself to pull right stick in the turns instead of chopping the throttle (yikes). Had great time with the trainer (Superstar 60) and only managed to break one prop.

I'm wondering if I need to adjust idle though. The engine idles great and will quit when the trim is brought to full "down" but I found myselt maintaining alt at idle when trying to bring her home. She would just keep flying down the field (4 feet off the ground). Ground effect??? or should I adjust idle or should I pull trim back a bit when I'm coming in toe land???

Anyway,
Thanks for the great info.
Fezz

ajvpb

My Feedback: (3)

Definetly pull the trim back as low as it will go and continue to run. You don't want it the engine to stall, but you also don't want it flying you around. Opening up the idle bleed screw should give you a slower idle. Again, I have the LA, and it idles quite quick for me. I haven't messed around with the idle screw much, but it gets the job done. If you find that it just won't slow down on the landing, put an 11x4 on it. Some would say 11x5, but with a bushed engine like that, it is better to let it spin up to higher rpms. I still run my engine, and while it isn't the best one that I have, it always will run, and should give you a great start to flying.