CastorTroy2150

My Feedback: (10)

Ok, there are going to ebe 100 people thinking im crazy.... but here goes... I have a 2.18 MDS glow engine on here now... couldnt figure my prop problem out....and it isnt a pusher prop for sure. Now Iwas always starting the engine at low idle.... Ill be danged if the engine isnt spinning CW!!!!!! But thats not the best part.... When Istart it at a high RPM its turning CCW!!!!Thats not all.... If Istart at a high RPM, its spinning CCW, then if Ibring her down to a really low Idle, and then let it sit for a few seconds, then throttle her up, she is now spinning CW!!!!! Iam going to lose my mind... HELP!!! Now i had to replace the plug, all i had was a OSA5, could that be the problem, unsure of what the other plug is.... running 10%glow.... Idont get it help!

j.duncker

My Feedback: (2)

A MDS like many other engines will start backwards. Mostly they will not run a high RPM and will either stop or reverse direction if the throttle is opened.

Because the MDS engine line was aimed at the European mkt where low nitro fuels are the norm they have a higher compression ratio than is normal for the US mkt.

If you have a head shim try fitting that. Try no nitro or 5% fuel and a cooler plug.

O YES if you get post telling you to use it as a door stop don't, The 218 is a great engine.

rcdude7

My Feedback: (264)

0 or 5%nitro would be better and a hotter plug. A enya #3, K&B1L, OS A3 would be a good start. Remember lower % needs a hotter plug.

It is not unususal for a engine to reverse rotation at a very low RPM.

CastorTroy2150

My Feedback: (10)

OK so let me get this straight, I am running a OSA5 and 10% nitro..... Not a noobie but never had to mess with engines to much. So when Istart the engine how should Ido it, and a head shim.... how exactly do Ido that and what does it do. I dont mean to sound stupid, but can Iget like a itemized list. For eample when starting........ and use ...... percent glow fuel....etc. when Istart should it be wide open? Iam really confused as Idont understand why it would be running CW sometimes whenIstart and CCW the other times. Should Iset the Idle higher?!Sorry if I'm not getting it I jsut am confused. Would my 10% nitro and A5 glow plug be to much? The biggest thing is Icould start it at a high RPMand it would run CCW, but in flight Icant afford the engine reversing..... so should Idle position be higer?

estradajae

I have seen that my engines will start clockwise when they are overflooded...and they usually run backwards untill they burn the excess fuel on the crankcase....

CastorTroy2150

My Feedback: (10)

OK Ihave used a back flip as that is what the instruction manual for this plane shows. However, when Istart at a High RPM and then come down to an idle, that is when it reverses and begins to spin CW.... Why does it happen at this point?! Ijust dont understand what the heck is going on. Not to mention that if Istart it at a low RPMit spins CW.. .I jsut need to know what combo of nitro, glowplug and anything else Ineed to use to make this thing run right!lol. Anyone with an answer as to wether 10% and an OS A5 is an ok combo?

estradajae

10% is too much nitro, specially because is a low nitro engine....

rcdude7

My Feedback: (264)

In general MDS enginesprefer a low or no nitro fuel with a hot plug.

Howdoes your engine run whenyou fly it? If the enginebehaves well in flight,don't worry that is runs backwards sometimes at idle. The engine cannot run backwards atpart throttle or above, if that is what you are concerned about.

CastorTroy2150

My Feedback: (10)

Well a little more testing showed some things. One, I have not flown it yet as Icannot get her running correctly.... Second she most definately was running CW at more then half throttle, it was jsut doing it earlier. Iwas startting by flipping the engine CCW, it was running CW..... Istarted flipping the prop CW to start her and she would run CCW. got 4 starts with only CWprop flips all were running CCWas a result of using this method. I will start running 5% with maybe a OSA8.... that should be a hot enough plug right? Ijsut dont get it. You jsut said it couldnt run CWat half throttle or higher....but it will...why is this?!!By the way THANKSfor all the great info guys were are getting there slow but sure.

Iam wondering could this be some sort of cumbustion problem? Could it be firing to hard or not enough? Anyone think that it is actually the engine itself? Ijsut want to rest my mind that its not a mechanical issue....and I can breath a little easier.... however, I plan on going to gas but would like to fly her as Idecided what gas engine to go with... As I mentioned a CWflip on the prop seems to get her running right, but she dies out sometimes when the glow ignighter is removed, but will run just fine as long as it is at half throttle or above. Transitioning from half to idle or idle to half to quickly causes her to die.... Ialso wish my electric started would work better, she is a BIT*H to get running until I get her some fuel. An electric starter would get it up there faster lol..... o well. Sounds like she may be rich too but Iwill mess with that later.... Thanks.

rcdude7

My Feedback: (264)

This is a new one on me, I have never seen or heard ofrotory valve two stroke engine running backwards at half throttle. I would imagine that the crank timingmust be way off to allow a engine to run backwards at such a high rpm?

Are you sure the engine isn't flooded when it is doing this?

TFF

I believe the crank timing is closer to center; so it is easer to get it to run the wrong way.  big combustion chamber and "low" top rpm allows the lower overlap.  I think low nitro and a gallon or two of ground running should fix it.  What size prop are you running?

CastorTroy2150

My Feedback: (10)

As noted before, I am not a beginner, Ihave never had to mess with engines, never had one flip out on me hah. But what would flodding have to do with running CW?!Im confused. And how would Ifix the timing? Are you fairly sure that it is the timing. I would gladly pull it apart and re-adjust it. Iam very proficient mechanically so Ishouldnt have a problem with some guidance. Runngin a JZ Jinger 20x8 Ibelive Ihave a 18x8a 18X10 is mentioned in the manual. The 20 was theone that came on the engine...thanks

Kimhoff

My Feedback: (22)

Run 5% if you can find it.  If not use the coldest plug you can find.  I would also turn the low speed needle in a 1/2 turn.  If it gets better good, if not turn it back out.

Compression, plug heat, fuel (nitro content) and mixture control the timing in a glow engine.  Your engine is firing early.  To fix this you will need to do one or all of the following, lower compression, go to a cloder plug, change to a lower nitro content or change the mixture setting (not in any order).

There is nothing wrong with the MDS engines, they just are not plug and play like some of the others.

TFF

Fix the timing?  Weld up the crankshaft where the fuel transitions from carb to crank case and then mill out a new hole where you want it.

CastorTroy2150

My Feedback: (10)

HAHAHA, thanks for the jumpstart for my brain.... if I would have really thought about what I was saying I wouldnt have posted that ahaha. Anyhoo, thanks for all the help, I will pick up some 5% and a OS A3 plug, think that will do the trick. Any particular brand of Fuel you guys suggest? So basically running the right plug and fuel/ nitro content will fix the problem? Sounds easy, I mean when she is running CCW, she is a prowerhouse! I had it tied off with the "Loop around the tail" method, it was a lot of weight and it wanted to pull my weight haha. Anyone who has ahd this model, it seems that I have to really open the needle valve to get her to run well... SInce I havent had the cowel off yet and I may gut her and place a one way valve of some sort to avoid filling the muffler. The original owner did not and she will hold a TON, ask me how I know .... anyhoo aparently the original owner did not.... haha will post my results!

estradajae

Any news from your engine?

I'm curious!!

Saludos,

Jorge

MJD

My Feedback: (1)

By changing the plug and lowering the nitro content, you are adjusting the timing, so don't feel bad.

The 2.18 takes some run time to settle in, and it WILL be cantankerous with too much nitro and too hot a plug.

Don't obsess over the backwards running thing. Generally this becomes a nuisance when the low speed is too rich, or your fuelling and/or handling operations siphon fuel and the crankcase gets loaded, and when compression ratio is high it can be much more of PITA. If you have the aircraft tied down or held securely, next time it starts backwards from behind, pinch the fuel line until the engine starts to speed up then die - as it is fading release the line and it should kick forwards - release the line when it does or a hair before. Get the engine cleared out, warmed up and properly tuned at full throttle, then come to idle again, and let it idle for a few seconds. Then pinch the fuel line again and observe the behaviour carefully. If it runs a long time, i.e. more than 2-3 seconds, and esp. if there is a noticeable speed increase as it leans out, then you need to lean your low speed mixture a bit and try again. If not, then it sounds more like crankcase flooding on the ground.

You mentioned you really have to open the needle to get it to run well. I hope you did! Don't count turns and compare the number to anything, it is meaningless and will lead you astray as it has others. Just set the high speed needle properly and if it is 6-1/4 turns out or whatever, good, remember that if you remove it. Also, reading between the lines and taking a guess here, be careful you don't try to improve the transition from a wet shaky idle by tweaking in the high speed.. unless it is grossly rich at high speed. Fix the low speed.

Also, just because it is a bigger two stroke, don't expect it to idle at 1200 rpm. With an overly wet idle mixture and dead slow (too slow) idle setting, kicking backwards and poor transition will probably plague you incessantly. Do you have a tach? If so, what sort of idle rpm are you aiming for?

MJD

With forward airspeed I don't think you're ever going to have the engine kick backwards in the air, and if it tries to then the mixture/setup is so far off I'd be surprised if you got that far.

laiosto

My MDS always started backwards when the throttle barrel was less than 1/3 open. I simply opened the throttle a fraction or flicked the prop backwards.