3w80 deadsticks

[wings&bolts]

Im hoping somebody can give me some new ideas here. I have an Edge540 87" with a 3w80. Its keeps dying on me. I have good gas and oil mix, I use amsoil synthetic, new spark plugs, new fuel filter, fuel line, carb is tight and doesnt seem to be leaking. My problem is that I can get it tuned and then next flight it seems to be running lean. I transition from mid stick to full throttle then it will start to spit and sputter then of course a wonderful deadstick. The engine is a twin cylinder.PLease help I bought the plane in a box and dont want to take home in a BOX.

[mmcgee.1]

Hi, Have you tried adjusting the high and low speed idles as factory settings are generally ok, but depending on altitude ect may cause such problems.

Regards Mike.

[wings&bolts]

Yes i have tried the original settings. I did notice last night i may have a cylinder head leaking.

[Dan767]

If you are using an in line filter between the carb and fuel tank, try removing it. Sometimes they develop air leaks that cause problems. Filter your fuel when you put it in, and get rid of the inline filter.

[IMAC Nut]

One thing I have had a lot of problem with is the screen in the carb. That will give you the same type of problem. Another thing that might be worth checking is the ignition. That will also give a similar sympton.

[brycesteenburg]

I have one of these engines on a 35% Sukhoi. I had a heck of a time getting it running correctly. But after 2 nights in the garage repairing, it runs like a top and starts the first flip after prime everytime. Here is what I did, First set the timing--28* at top dead center make sure of this first. Remove the carb and phenolic adapter, disassemble carb, check for proper gasket seal and clean the inlet screen. If nobody has messed with the needle and seat setting in the carb just disassemble, clean and assemble. Do not change this height or pressure setting. Check the reeds for cracks and that they close properly around the cage assy. Check the phenolic block for cracks and stripped carb bolts, repair or replace as nec. Make sure the throttle plate closes completely in the bore and open the plate with the throttle stop screw about a 1\4 turn, just make sure the plate does not stick in the bore when closed fully. Reassemble everything and set both needles to 1 1\2 turns out from lightly seated. Choke on, WOT, no ignition, flip till you see gas running from the carb opening. You have now filled the carb with gas and primed the engine. Open choke, WOT, no igniton, flip a couple of times to clear fuel through engine. Secure your plane, open choke, have throttle at 1\4 open to slightly under, turn on ignition and flip engine to start. This should get you started and ready to tune. Remember, the Tillotson carbs are very sensitive to small movements of the needles. Low needle is always closest to the engine. Bring engine to operating temp for a few minutes then start tuning with WOT and high needle first. Set your needles with the engine off, then restart each time for proper RPM.
Once I got the engine running crisp, clean and snappy transitions, I went to the flight field the next day. My start procedure is, Choke on, no ignition, WOT, flip 5 or 6 times. Choke off, 1\4 throttle, ignition on, flip once and it fires everytime. Had to set both needles about an 1\8th of a turn out from the garage setting. Take your time and do everything methodically. You will be rewarded with an engine that starts, runs and has very good power consistently. This is how I do all my engines and works great for me.

Bryce

[CRUISER]

Just because an eng is new in box doesn't mean every thing is to factory spec's ! The lean condition could be from turbulance at carb & or vent of carb diaphram cover, but that info has been covered quite well on this site so i'll move on to what i found in my latest eng. I found that it was running lean even with ideal needle settings, so, i checked the pop off presure and found it to be way up at 18+lbs ! it should be approx 11lbs. I use a syringe full of mix fuel, with some fuel line, a tee, and an air pressure gauge that reads in low increments. hook up to fuel inlet and apply pressure till it pop's off and note pressure. A high pop will make the run lean and needles will be out too far for keeping them tight on spring. I almost lost my high needle. if it pops too low it runs quite rich and the best info i have found for these eng's is they like it in the 11/12 lb range. I have found new springs to give a pop at 2.5 lbs and need to be stretched a bit at a time and rechecked till you have the range you want. If you try your hand at this you will see that the spring can be tricky to deal with and i like to keep it uniform looking. When the pop is correct your motor will run sweet !
This is by no means the only possible problem, but is worthy of checking ! If your pop is at a high then it could well be Your problem, this is always the first check before bending the tab and prefered to bending the tab. If the pop is not in range then bending tab will only ruin the tab. A good source of springs is the local saw shop and they do come in differant sizes and tensions but if lighter than what you want you can adjust it till perfect.
This is not law but what i have discovered and info i use for my motors, If it don't work right there is a good reason ~ and the factory is not perfect ! After all another factory puts the carbs together and ships them by the crate.

[wings&bolts]

Thanks for all the info now I have a new begining.

[cloudshaker]

Check your reeds for warping also.
Let us know what all you find. CS

[Tired Old Man]

Definately check the reeds to assure that they are closing completely! If you have fuel leaking from around the base of the cylinder tighten the head screws. You don't have to kill them, just get them equally tight.