Hi!
I've got a Evolution .36 engine in my Extreme flight outlaw. I've only had it running about 10 times, without any apparent issues.
Last time I got to the field, I just couldn't seem to get it fired up. Last time I also had problems, but managed to start it at last. But this time, I noticed it would not suck any fuel!
When trying to prime it, by holding the finger over the carburetor and turning the propeller, it would not suck any fuel!

I could hear a "fizzling" sound when turning the propeller and it would loose compression if I held it under compression. So when I got home i checked it out more closely, and here is what I found: http://www.youtube.com/watch?v=N63A_TREwf0
It appearantly realeses air between the liner and piston!

So my question is, could this be the solution to why it won't suck any fuel? Or is this normal?(I don't have very much experience with glow-engines)

Or could it be something else causing the problem?

I would guess that there is some kind of obstruction, probably a small chunk of dirt of some kind blocking the main needle valve. Try hooking up a clean piece of fuel tubing to the connection at the main jet, and blow through it, you should hear some air going through with the carb at full throttle. If that works, try blowing air backwards through the carb pickup line. Is there the possibility that the pickup and vent lines (from the muffler) got swapped? It definitely won't prime if you're sucking air...

Well then.
Just ran some fuel through the main needle valve, with the needle out, and now it sucks fuel with no problem...
Thank you very much sir! Should have checked that before asking... [:@]

Realised that no fuelfilter was installed either, so now it got one, and hopefully there won't be more trouble with this engine

By the way, is this loosing compression "problem" normal? Shown in a video: http://www.youtube.com/watch?v=N63A_TREwf0

When it warms up, it will seal better. If it starts and runs, should be no issue.

Get a O.S.!


Pete

What??
An overprized engine? Why?

I've got an ASP on it's way for $50. Now that's an engine.

When we say "loosing compression" we are not referring to what you are calling compression loss.

What you show in the video is perfectly normal and indicates an engine with VERY GOOD compression.

Air/Gas will always escape past the cylinders, particularly if there is no piston ring ( as in many ABC engines ) to further act as a seal... and even piston rings have a gap in them that tends to let air through.

The only thing you want to assure is that the air/gas escapes as shown in your video somewhat slowly.

No compression or loosing compression, refers to practically no resistance to moving the cylinder into the cylinder head because ALL or almost all air/gas is escaping very quickly.

I have a few engines that if they are fully dry with no oil or fuel in them after not using the engine for a while, the prop will spin almost freely.

Yet once fuel hits the engine, there is pronounced resistance to flipping over the prop and the engines start and run just fine.

So don't worry about it.

The engine is fine and you've already cured the fuel flow obstruction...

One hint about Evolution engines.

You may see a slight grey goo coming out of the muffler. This is caused by aluminum particulates being shaved off the back cover and other surfaces as the engine wears in. This is perfectly normal for Evolution engines and a few others.

However this grey goo can harden and cover the pressure fitting inlet nipple.

It is a good idea to remove the pressure tube from the muffler at the start of each flying day and stick a small allen wrench down the hole to clear it of any obstruction. Actually it's a good habit to get into with any engine.

Because O.S. works.



Pete

I have a large cyringe type injector for like marinating turkeys that has fuel tubing attached and can connect to the needle valve. I had an Enya 45 that sat for years and would not suck. Once I hooked up the injector and really put some pressure on it, the clog broke loose and the engine runs awesome.

you are correct, OSworks, but the other brands work too and for half the price...

I've found most of the Evolution engines to be very reliable ( except the discontinued NX 1.00 ), once you get past the limiters.

They have a couple of quirks, as do most engines ( including O.S. engines, e.g. the need for that thrust washer and woodruff key), and once you understand those quirks they run quite well...

e.g. in Evolution's case

- Limiters on the Needles
- Grey Goo during break-in

Yes, but do they last as long??? Just busting chops but there is a hint of truth of what I wrote. I do have a Super Tigre .51 and it was horrible! Once I tossed the stock carb and swapped it with a Perry it's now just as good as my other 2 stroke O.S. engines. But the price I paid to get it to be dependable, I could have bought a OS instead.

I got the engine for free when I bought a used plane that was hanging on the ceiling at MLHS. Super Tigre engines themselves aren't bad, but the carbs are a hit or miss. Mine was a miss.

I've had no luck with glow Evolution 2 stroke engines. They either leaked from gaskets, over heated, lost compression or bearings wore out quickly, or the rings went bad. I had 3 of them- 46NT, 46NX and the 61NX and the eventually they wound up in the trash. But I did find that the pistons do make excellent key chains!

So far, the only engines I like the most are Saito and O.S. and to me they are worth the extra cost.


Pete

yeah you are right, I have a 46 NT and I love it, but I must admit that it won't last as long as any OS engine... OS engines are easier to tune than any other engine and that is a fact  but sometimes we don't have that extra $40 or $50 so the other brands become a good option.

That's true. I'm not rich by any means and I get behind on the bills at times like most. What I do is I try to save, it doesn't matter if it's 1-5 dollars at a time after bills are paid. For me the hardest part isn't so much in saving, but the wait that it takes. I figure the term that's used most for it is called sacrifice.

My parents survived the Great Depression ( mother is in her 80's and still alive) and some of those skills that they taught me help keep me in this hobby. I'm just glad we're not quite there yet to how bad it was in the 30's when it was really bad.


Pete

The good thing is that I got my problem sorted out
Thank you all for your answers, tips and tricks!

Hopefully going to the field to fly tomorrow, between the rain-showers here in Norway this time of year...
Haven't been able to fly for weeks.

Hope all is well and I hope your problem is solved, that's why most of us are here to throw you idea's until it does work.



Pete