kenmeade

A black carbon/oil mixture leaks from every muffler joint including the center section at both ends, main central bolt head and rear nut. The leaks make a mess which is hard to clean - plus it looks like crud. I wanted to weld it solid but the center section is SS so that won't work. Tried steel epoxy. Tried high tem silicon gasket seal. Tried small "O" rings in the center SS joints. Maybe there's tricks that make one of those work? Any ideas?

A friend said there's OS muffler that will fit. Any info there?

Question. Is the center section of the muffler designed to "tune" the exhaust system?

Is anybody making a replacement part that can be welded to the body sealing it for sure?

Thanks - Happy New Year!
Ken

jjoos99

My Feedback: (12)

My muffler actually came with two orings, one for each side of the center section. My center section is made of aluminum. I cut it down to fit my plane. Havent ran the engine yet to tell if it is going to leak. it was posted earlier in this thread that removing the center section would reduce performance. The guy I work for said as soon as he looked at it that it would not stay tight. Seems the different types of metal will expand differently causing the main through bolt to come loose.
Jeff

Russmall

An OS 46AX or FX muffler is a perfect fit and will end your muffler problems. It's also less noisy than anything else I've tried.

kenmeade

Good. Thanks! Did you by chance check top RPM with the different mufflers? I believe that the stock muffler center section was put there to "Tune" the exhaust for higher RPM. That's the reason for the question. Do you know if the OS 55 or 61 will fit also? Ken

kenmeade

Factory "O" rings? And the center piece is aluminum? That's interesting since I bought a extra muffler thinking I would have it welded up but the SS center piece got me - I thought it was aluminum! RE the center section I believe it was put there to tune the exhaust like a tuned pipe for more RPM Thanks for the info! Ken

the pope

If your keen to weld the muffler have you tried to source the correct size aluminium tube that would suffice ? Cheers the pope

kenmeade

Good idea pope. McMaster Carr is a super supply house for that kind of stuff and I have calipers to measure the tube. It's SS and I hope there's a alum equivalent and I don't have to buy 100 feet to get 1.3 inches of the stuff. Hi!

jjoos99

My Feedback: (12)

I just bought my engine less then a month ago and it came with 2 orange o-rings for each side of the extension. I cut the extension in half and had to put it in the lathe to machine in the stepped down section and it was aluminum. No you have to wonder which metal is the improved version?
jeff

the pope

Generally things workout cheaper if you can get stuff off the rack . I couldnt see evolution getting stuff made especially when there's something thats going to do the job thats nearly the right size . I have one of these engines with the macs muffler on it and dont know where the oem one is to measure ( always a option for you and may even be cheaper if you need to buy the tube and get someone to weld it . Most fabricators and welding shops have a minimum charge to keep time wasters away . When I was doing this for a living I would always say that I may fix it or f@#ck it just in case the stuff wont weld properly which maybe the case in this instance .If it was me I would get the macs muffler and leave all your troubles behind . Good luck with what ever path you choose from the pope

kenmeade

Just checked the Macs and they said - "Evolution .52-.60NX & 10cc GX(gas) (MACS Product Does not guarantee this muffler when it is used on the Evo.10cc
GX(gas) or other gas motors)"

Plus they want $49 and shipping. Thanks for the idea and it's a good one. I'll call them to see what the problem might be in using one on a gas motor. But you had success so will see. I understand the welding situation.

Does you motor still have black goop exhaust? I've been using a "blend" oil. Will all synthetic help there do you know? Ken

the pope

Im not sure the reason behind the macs muffler thingy but I.I.R.C. its been discussed here somewhere before and I think it was pretty much a non issue . Perhaps someone else could chime in here . If you want to see goop , try the norvel as a coincidence I was flying mine yesterday on a scanner and its turning that plane to poop not goop pretty quick . Doesnt help when the covering is layered into the wind so any breeze and crud is being forced under the covering and the printed on covering is turning brittle and yellowing at the rate of knots . Still like the engine though and I clean the plane between flights which you may have to do to help if its a problem but a well sealed muffler has gotta help . The norvel uses castor but I would use a good quality synthetic like stihl hp ultra etc. As for the price , well its good value to me . Would hate to go through all that rooting around and expense and then find I was still up ****e creek anyway . Cheers the pope

ahicks

My Feedback: (2)

I've had good luck with the Mac's pipe to date. I do believe it might actually be making a little extra power, but I haven't proven that to myself yet. I also have a second engine (that's still breaking in) using a Bison Pitts type muffler. Equally good luck here, though I've heard of some others having to block one of the 2 outlets to get enough muffler pressure. That's not been an issue for me.

Evo w/Bison Pitts was in a Phoenix Decathlon, and although it flies fine (with plenty of authority), it's not my favorite plane. That hardware is currently being transferred to an Phoenix Extra 300 that Santa dropped off recently. By time I get this plane sorted out, the engine shold have enough time to do a fair Mac's vs. Bison Pitts comparison. First engine is in a .46 U-Can -Do.

In my experience, you'll see a noticeable difference in the amount of black crap as the engine breaks in and you get the carb adjustments ever closer to the perfect settings that can only happen over time. -Al

BTW, the fuel running out the carb issue, noted a while back, turned out to be a really tiny crease in one of the internal diaphragms. It wasn't allowing one of the "flappers" to close properly. That part replaced, we're back in business.

kenmeade

Pete - RE the Evo 10cc
1. Will 100% synthetic oil reduce the amount of ugly black hard to remove crud in the exhaust while using "Blended" oil?
2. Is there a method to stop the muffler joints from leaking this stuff? Somebody mentioned that his came with "O" rings installed in the center section. Mine didn't. Standard "O" rings installed blow out after a few runs.
2. Is the stock muffler "tuned" for a increase in power over other designs so should not be modified in shape?
3. Is the stock muffler pressure required for appropriate fuel delivery to the regulator? Therefore should not be changed?
Note. The motor itself is a very good design, powerful for that size running gasoline and runs super good. But the exhaust is a model destroyer in the long run, even using an after market silicon exhaust diverter which does not help because of the muffler leaks in all of it's joints including the threw bolt head and nut.
Ken

kenmeade

Pete - RE the Evo 10cc
1. Will 100% synthetic oil reduce the amount of ugly black hard to remove crud in the exhaust while using "Blended" oil?
2. Is there a method to stop the muffler joints from leaking this stuff? Somebody mentioned that his came with "O" rings installed in the center section. Mine didn't. Standard "O" rings installed blow out after a few runs.
2. Is the stock muffler "tuned" for a increase in power over other designs so should not be modified in shape?
3. Is the stock muffler pressure required for appropriate fuel delivery to the regulator? Therefore should not be changed?
Note. The motor itself is a very good design, powerful for that size running gasoline and runs super good. But the exhaust is a model destroyer in the long run, even using an after market silicon exhaust diverter which does not help because of the muffler leaks in all of it's joints including the threw bolt head and nut.
Ken

JoeyCoates

I have a question for you guys, are you still running a 20:1 mix in your 10gx's? I know Pete had responded quite a while back that they may relax the oil requirements in the engine due to the late addition of a roller bearing in the big end of the con-rod (which I believe was one of the main reasons for so much oil to begin with as compared to most other gas engines), but I have looked at the manual online and it still lists 20:1. I have other gas engines and it would be much easier to have one can of 32:1 to use for all of them so I was just seeing if any of you were using such a mixture. I really do not think it needs so much oil, if it still had a plain bearing in the big end then maybe, but even being of ABC construction 20:1 just seems pretty excessive.

ahicks

My Feedback: (2)

Joey,
Was just talking about this earlier. I have 20 and 30cc planes as well. When the 20's first came out I was running 50:1 in my 30's, and switched them to 32:1 for the simplicity of maintaining one mixture that works well in everything - like you are considering. Well, now that I've been running the 10's as much as I have been, I've switched everything to 20:1. There have been NO notable downsides to doing this to date (end of first season). I did have the exhaust off an RCGF 20 the other day as I was curious what the ring groove looked like. I've been hammering on it all season, so I was half expecting to see it loaded up with carbon. Happy to report there was no problem at all. I'm sure this is a result of running a quality oil.

It should be noted that with the tiny amounts of fuel these little guys are using (10-20cc engines), if you do not increase the oil content in the fuel flowing through the bottom ends, you run a much higher potential of smoking an already highly stressed bottom end....

It's not like running more oil is costing you much in the way of performance. It's not like you're going to be able to jump to the next larger prop size by switching to a leaner oil ratio. The ONLY down side I've noticed is cost. I'm now going through twice as much oil as what I used to. From where I'm sitting, that's a small price to pay for being able to fly these 10-20cc gassers again. They're so much friendlier when it comes to handling/care/feeding, the 30cc stuff is now getting dusty... -Al

kenmeade

Yes, on a NOS 2 years old maybe with a "Blended" Poulan 2 stroke oil and after 1 gallon of 20/1 the con rod slop was bad so sent it in. They replaced the "cyl/piston set" free but I haven't opened it to verify. So - maybe - 20/1 isn't enough oil? Or the wrong oil? Maybe they updated it by putting in rollers at the same time?

RE oil, in the early 40's we ran 3/1, 70 SAE motorcycle oil. It worked. I did a "Whoop's!" and wondered when I saw the 20/1 knowing the rod had to have plain bronze.
Ken

flyinwalenda

My Feedback: (5)

I am still running 20:1 using Klotz and 100LL after several gallons and the deposits are minimal...still less than a glow but a little more than a larger gasser .. Not worth the risk of thinning out the mix.

locoworks

any body run one of these engines for a season yet? and if so how has it gone?

flyinwalenda

My Feedback: (5)

4 gallons + so far which equals around 110 fifteen minute flights ...plus or minus. Still going strong !

2walla

My Feedback: (10)

The OS mufflers are better and don't leak. One thing i noticed is that the OS through bolt is 2-3 sizes bigger in diameter. I would drill out the POS evolution and try a larger diameter bolt if i couldn't find an OS muffler. Once you get a muffler that doesnt leak it runs so much better. Come on Horizon fix the problem....

ahicks

My Feedback: (2)

I have a season on one, and would not hesitate to recommend the engine.

Like it enough to have purchased a second one, but still figuring out what they can/can't do. Recently learned, do not drag your feet coming up through the suggested prop sizes during break in. Get that 13x6 on there as soon as you can. They really quiet down and come alive with that prop.

BTW, one engine is running a Mac's pipe, the other a Bison Pitts. No problems to report with either.

locoworks

thanks for the replies guys

bmcd

Hi all
My 10GX has done about 8-10 litres and runs a 13x6 APC. I am getting 9450 RPM on the ground. Idle to max transition seems ok but after WOT for a few secs, the return to idle takes about 7 secs.
This all at sea level at 28 degC.
Is my max RPM within the norm and any comment on the slow return to idle will be appreciated.

Thanks, Brian

Joystick TX

It's been quite a while since I had that problem. It seems like it was due to the engine carb being set too lean. I know ahicks will know for sure, maybe he will chime in here.