My simple comparison of the Stock muffler against the OS muffler with regards to sound? The 10cc in this video with the OS mufflers is running on its first tank and is running really nice on a APC 10x6 run-in prop at max RPM at almost 13k... amazing for a brand new engine... very easy to tune and very reliable..

Very nice
 

engine sounds good with ether e
muffler. The OS one sounds a little deeper,

Would have been nice if both mufflers had been tried in otherwise identical scenarios. With one run on a test stand, and the other installed on a plane, My impression is that the plane added/changed some harmonics.

Yep... as Al says, the differing mountings can resonate differently.

Yes I agree, it definately changes the harmonics, will make a new video once I have them both in a plane and at the field...that changes the sound quite alot... just gotta wait for the all the snow to melt first :)

I have an older non pumped version of this engine. It has been in the plane for several years and only started and ran once. Just wondering if I shouldnt just go ahead and buy the pumped carb and install a pressure port? I hope to join a club and finally fly it this season. Looks like the carb is around $35
thanks
Jeff

Jeff... You didn't outline the specific reason the engine was run only once so it is hard to say if you should upgrade the carb.

I've two of the vs 1 engines and haven't had problems so continue to fly them with the non pumped carbs. If they were a problem, I'd upgrade them.

I was flying at a runway behind my home and lost the use of the runway so the plane I had bought this engine for has never flown, just test run in the back yard. Hasnt been started since 2016. I just thought that if it needed done now would be a good time while snow is still on the ground.
Jeff

Well, judging from all the complaints from the guys that have the non pumped version, I'd go ahead and convert the carb.
Pumped is always better than non pumped. It would be much more reliable. You don't want to crash just because of a flame out do you?

I sure do like my pumped version. Sounds like a harly Davidson to me...

Bob

Well, if you have nothing to do and all day to do it then go ahead ;otherwise why bother ? The original design works very well .

I have one of the first examples of the Evo 15cc and fly the snot out of it. One of the frustrations people ran into, was that the fuel line provided with the engines was not much better than Tygon for the pressure tap line, and Tygon is unusable on the muffler, due to the heat. Simple solution, just use good old silicone fuel line on the vent line to the muffler, holds up just fine, you just can't use it on the carburetor line which is constantly filled with gas.
Pete

Yeah, but muffler pressure to the fuel tank is so yesterday.
A pumped carb eliminates the need for that.

Just sayin...

Bob

Thanks for the hint, pilotpete. My Saito FG-14C will not run right without muffler pressure.

I'm running four Evolutions with muffler pressure, 2-10cc, 1-15cc & 1-20cc and they are all running fine. I'm also running three Saito glow engines converted to gas, a 90TS, a 1.25a, and a 182T all using muffler pressure with the stock carbs.

Muffler pressure does work with gas just as it has with glow for forty years.

Absolutely There are many here who are using the first generation engine with success. If you properly break-in the engine, seal up the muffler and header joints properly, and use a good quality fuel line, the engine runs fine.

Adding to what Brian said, a gotcha with these small gas engines on muffler pressure is staying with a fuel tank sized for glow. Large tanks produce larger swings in mixture settings and should be avoided and are not needed because gas consumption is less than half that of glow..

If the plane was designed for a 12oz tank when glow powered, a 6oz is all that is needed or should be used on gas.

You got that right ! Still got to work on that DLE 30 hub change. :rolleyes:

You will need an 11mm extra deep wall thin socket to undo the crank stub nut OR as an alternative you can shorten the stub by cutting it so that a regular deep socket can work.

crank stub
 

Thanks Karol, for the reply. Have a super weekend. Your friend, John

If the diameter of the hole inside the socket is too small, it is easy to drill it out so it will fit over the crank stub nut. I have had to drill out several of my sockets because the hole would not fit over the threads of bolts.

What are you guys using for an exhaust extension on the 10gx?

Double check me, but thinking the OS 40, 45, and 55AX all use exhaust ports that line up with the 10gx. Many are using OS mufflers due to all the trouble with the Evo mufflers....

Yeah, the distance between mounting holes is 37mm. I need to space out my muffler about 1-3/8". All I can find is a 1/2" spacer.

Dubro makes an extension that can be drilled and cut to length, pn 213. Just not sure what the dimensions of it are.

Horizon website now shows this engine as discontinued. Oh well.....