Hi,

I need help with my Saito 82. Engine is new may be 1 gallon thru. It is installed on Seagull Harrier 46, without cowl. It swings 13x6 Master airscrew prop and I am using 20/20 YS blend fuel. It was working nice since I bought it, start with the first flip and never died in the air. 2 days ago I was flying and it quit on me, I landed safely. I tried to start it and it was perfect idle, but when I am adding a throttle it quits right after ΒΌ of the throttle. I re-adjusted needles, low to 2 turns out and the high to 2 and the half. I let the engine cool off a little, and it was running good again. I tool the plane in the air and after 5 min 40 seconds of flying it quit again during the loop. Engine seems to be a little hotter than is should, but it is not lean. I am always running my engines a little rich. I also notice that if I put the pressure on the low-needle while engine is running, it drops rpms and quit.
What can be a problem? Thank you in advance.

Putting pressure on the low speed needle pushes the throttle barrel inwards and leans the mixture.

You may need to open you idle mixture screw just a little bit yet?

Do you have a fuel filter on the fuel line before the carb ? You may
have a bit of crud in the carb which would lean it out. []

FBD.

You can reduce the end play of your barrel by tightening the spring loaded barrel guide screw; be sure your throttle opens and closes without stalling your servo. Besure your throttle control rod is not pushig the barrel inward.

Yes, I am always using filters on all my planes/engines.

It is good idea. Thank you, I'll double check that when I'll get home. Unfortunatle, I still can not figure out why engine works fine for 5 min and then quit.

Hi there,

I had the same symptoms with my FA82. I use mine to power a Calmato sports turning a 13x6 MA as well. Almost the same engineconfig.

I read that you use filters on your fuel setup. Thats OK but.... I used a filter placed in the fuel line to the carb resulting in somewhat irregular rpms. It seems to change in rpms at full throttle. I got rid of this filter (I tried different kinds and brands) and changed the copper clunk for a viltclunk (a clunk with some kind of fabric wrapped around it... don't know what it is in English).

This gives you the advantage that it draws fuel in the fabric and with that it filters the fuel before going to the carb. The fuel flow is more consistent with this setup. It worked wonders on my FA82.

Something else could be that the fuel line in the tank came loose that could explain the 5 minute flight before engine failure (especially in a loop). I had the same problem with a FA120 that quit on me after 5 or 6 minutes. The fuel tank was empty half way and the fuel came under the brass tube (where the silicon fueltube came off inside the tank) that exits the tank causing the engine to run horrible and then to quit.

Well, there you go.. hope its useful

(my apologies for the poor grammar, I'n not American or English [:-] )

cheers,

Tjen il-vec

Thank you Tjen il-vec, I already visually check the fuel tank and it seems to be ok. I'll probably take it apart anyway just to make sure it is not the problem. Actually, first thing that I thought is that I lost the clunk. It happened once before and the symptoms were similar. It would be very nice if this problem will be in fuel tank.... (easy fix)

Your welcome

I hope it is traced back to your fuel setup. That rules out any problems with the engine and it's an easy fix. Try the viltclunk, the nipple is a bit larger so the chance that you lose it is very small. If you decide to use this clunk, get rid of the filter in your fuel line. 4 strokes can be very critical in performance with any debris, air or obstruction in the fuel (flow).

Good luck!

Great engine by the way, excellent power to weight ratio!

Cheers