your system is 4.8 - 6 volts. Make sure you dont go over that value, when connecting to your ignition system. You do not want the new ignition system, as it costs roughly 180.00. The new system, also uses two sensors instead of one for signals. I can detail what they are for, if you are interested. Just read your manual (the one you posted) tune and time the engineas written, a few posts above this one and go fly. Learn from your engine what it needs. Putting time on the engine will give you that. Then when someone else has the problems you had, you will have first hand knowledge and be in a position to help someone else out.

Glenn

Guys,
All is well I'm just a little concerned that I'm leaving some RPM's on the table. I'm only turning about 5200 -5300 RPM's on a TBM 24x10 2 bladed prop. Does this seem right to those of you that have a 58GX? According to the manual this seem kind of low the sweet spot is around 6000-6400 RPM's. It does pull very strong , and doesnt putter or anything but 1000 RPM's seems like a lot of power I'm missing out on? Anyone want to take a guess as to what's causing this? Is it the prop? Too large? My goal is to use this engine on a 30% Lanier Yak and do some 3D Hovering mostly. The Lanier is a bit of a pig so I want to squeeze as much power as I can.

Horizon was using a Mejzlik prop and their rpm's would be higher because of that but I doubt 1000 rpm difference

I have heard that TBM props will turn a lower rpm than others. Try a Hawk from Southeast RC engines. Decent prices and no shipping.

$50,

I owned the same engine and same plane. I ran a Xoar laminated 23x8 on mine. 6700rpms... very strong motor...

As to your original question...

Make sure the gasket between the cylinder and case is not leaking (and sucking in air). My engine had this gasket replaced 3 times... it's a problem area for the engine..

My engine would start easy, and run fine, until about 10 minutes into the flight... and bam.. she would just shut down... I changed everything, fuel, plug, fuel line, tank, etc.... I even baffled the cowling.... that help some... but the engine would still just shut off...

I replaced the gasket and it fixed the problem... but the replacement gasket from Horizon would fail after a few flights... It's really a same, because the engine was smooth... and a big time power house...

Evolution's benchmark prop 24x10 mejzlik 6900.... the only way that number could be attained is with a tuned pipe

i agree they are swesome motors...and is a motor i would consider buying...could possible be the strongest 50-60cc engine out there

Hi!
All MVVS rpm readings are either with a cannister or tuned pipe. My MVVS 45cc engine with the small MVVS cannister silencer turns a 24x8 Mentz (Wooden prop) at 6600 rpm. It also turns a Top-Flite 24x8 at 7200 rpm.
I assume that your readings is without a cannister silencer..?!
I recommend using one! You get more rpm (power) and your engine will not sound like a moped..

P.M. sent Jaka

You may be on to something. My friend noticed a little oil at one of the head bolts. It turns out it was a little loose. I snugged down all four bolts. I ran a full tank on the ground just trying to get it to die again and you know what it did but it was becuase it was out of gas lol. We sat an pondered for a while and it turns out it was out of gas.. I'll have to to check the head bolts again and see if it's still leaking if it is I'll order a new gasket but my hunch is that I may have the same issue as you did. The reality is that I did notice a few other things when I started taking things apart. Like both carb bolts were loose, I had a ton of junk in one of the small screens in the carb and the fuel line in the tank was floating as the clunker had fallen off. The gas was about 1 1/2 years old. The plug looked good and the battery seems to be fine and all of the fuel lines except for the one in the tank looked to be in good shape. So at this point I can't say with any certainty that the problem is fixed. I did replace the clunker with one that has a screen the other thing I noticed is the manual said use medium fuel line and mine had large fuel line other than that I'm mystified. So if she dies mid flight again I'll replace the head gasket.

Did Horizon tell you the torque to tighten the bolts down? I'm assuming the head and may be aluminium and the rest of the casing is steel? I would think that if the engine overheats it could loosen the bolts causing an issue.

Oh I have a BCM (Bisson Custom Muffler) pitt's style muffler I belive they are called. I thought they were supposed to perform better than the stock muffler and are a little lighter. Maybe I'll get a new gasket and get a CF prop see if I can reclaim my 1000RMP's

I am getting about 6300rpm with a 24x10 CF prop, premium gas, and Redline 40:1. I have used about four gallons and it seems to be waking up. It does have a lot of power and now that I replaced the ignition, it runs great. The original ignition was causing dead sticks on almost every flight, lots of close calls. I have it in a AW Ultimate.

Here is a short video of the engine running.
http://www.youtube.com/watch?v=UCtCj44Aw-A

Did you replace it with a new 4.8v ignition or did you go with the 6v ignition? If the latter what was the cost? I noticed you live in Norcross what club do you fly out of. I'm out of GMARC up in cumming.

It is a 7.4v MSR ICU-L I got from Pe Reviers in the Netherlands. Saved about $100. Horizon replaced the defective ignition for free, so now I have a spare for my Evolution and MVVS engines, it works on all single piston engines. My son and I fly at Stone Mountain(SMRCF). A bunch of our members moved to GMA. I would like to drive up there one weekend, the photos look nice. I have a 45cc evolution that is almost four years old and seems to run better everytime it is flown.

Hi,
you are right. I used to have 58 ccm and I used Mejzlik 26/10. I had 6000 RPMs with canister.

Now I have 80 ccm and with same prop 26/10 turns 6660 RPMs.

When you replaced the gasket you had to remove the entire head correct and when you slid the piston out of the head the ring expanded right? Do you need a special tool to compress the steel ring around the piston? I'm having problems the steel ring has got a split in it and it's a ***** to compress and slide it back on. Is it broken or do I need some special tool??

What a pain in the ass this is becoming!

Look for the locating pin in the ring groove

OS 50 locating pin

Sorry can you elaborate please. Very new to all this I didnt realize changing a gasket would be such a chore. What do Ido when I locate the pin in the ring grove? Ordered the piston ring last night. Do I need a special tool or anything. If it's like my car rebuild kit it wont come with any instructions.

Many two stroke engines have pinned rings to keep the ring gap in one place so it doesn't get hung in a port

There is a pin down through the ring land or straight into the ring land

There is a notch in the ring that fits over this pin. It locates the ring gap away from any intake or exhaust ports

If you try to fit the ring any other way, you cannot get the piston in the cylinder

Ah good to know thanks for the info.

I had a problem with a new out of the box engine..It had the same symptoms as yours...I ended taking the carb off and the reed block, and found the reeds were not aligned over the holes. It wouldn't draw fuel for anything. Lined it back up and it ran.

w8ye
Do you know if the 58gx has this? You refer to "Many two stroke" engines is this including the Evoloution 58cc GX? That's what the thread is about. I don't see a pin on the ring? Maybe it broke off but I cant see it? Anyone else know? Am I making this harder than it seems. I'm just trying to replace the ring on the piston. I broke one piston ring already don't want to break anohter. Anyone??? Is there a trick or special tool? Or do I need to let my genlte wife try it instead of me man handling it with my big fat fingers that cant squeeze it in far enough.

Maybe Pe can answer this.

A friend has a couple Evolution 58s but he's never had them apart. I do not own a Evolution myself.

On some model engines, the pin is in the ring groove on the piston. The ring has a notch that fits over the pin. There is no pin on the ring

Also, the notch that is in the groove, both ends of the piston ring butt up againest it. I put them on this way. Use some type of oil. I start with one end of the ring and work it around the top of the piston until it is all the way on it, maybe a 16th of an inch or so, then slide it down until it is seated into the ring groove on the piston.
then slide the cylinder onto the piston till it meets the ring. Lay the cylinder on a table so the connecting rod is up. Push the piston ring in so that it is compressed into the groove on the piston, then carefully slide the piston into the cylinder.

I got my piston ring yesturday and put it all back together thanks. There is a pin in the groove so I lined up the piston ring with the notch on both sides of the pin. It took a little work but was able to slide it in with no issues. Thanks for this. I was told that the side with the pin must be facing opposite side of the exhaust port. Not sure why but that's what Horrizon Hobby said.

Onto another problem. I rebuilt the carb and last night was the first time I started the plane with the rebuilt carb and new piston ring and head gasket. A new problem has arised. This one is wierd. Choke on and throttle open I had to prime the carb with a little gas since the carb has all new gaskets etc... She started 3rd crank which is great. But what's wierd is the throttle is non responsive. I see the throttle tranisitioning from low to high when I move the stick, but the plane still sits there at high idle. Now if I turn the choke off then it almost transitions into a wide open throttle??? I have to quickly trim the idle down. Does this make sence? Anyone see this before? Anyone want to take a stab at this one?

Thanks again for everyone's help on this. I just wish it would work so I can go out and enjoy the plane. It's spending a lot more down time than I would have hoped for.

Sounds like the needle may be stuck. Check the little for to make sure it is around the tip of the needle.