evolution 50 cc gas engine troubles
 

hi
last weekend
took my extra 260 27% with the evolution 50 cc gas engine.
this was the third flight with this engine.
i am still running gas with 1:30 oil mix, which came with engine

was able to start engine and had to play with HSN and LSN.

got engine to turn the 23 x 8 prop at 6400 rpm.

once i felt engine was warmed up, about 3 minutes i would say.

did one final throttle up and down, checked engine could idle and would not turn off
then took off

plane was up in air maybe 2 minutes, or less, then engine cut out. had dead stick landing with damage to prop (35$) and then landing gear broke (carbon fiber).

i have fixed everything since then, and took airplane to back yard and turned engine on again.
LSN is 2 turns out
HSN is 1 3/4 turns out

then after about 5 minutes, of me running engine TWO, then engine started to cut out.

the ignition batteries are lipo, and they are fully charged.

the fuel is new, not old.

i figure something is happening once engine reaches certain temperature. I dont want to say it is overheating.

outside temp here is 88 degrees

and the airplane does have a cowel on, but it has adequate opening and exit is even bigger for airflow.



any one have any suggestions?

BTW, i did remove the spark plug, and the recommended gap is between 0.6 mm and 0.7 mm

the gap i measured was about 0.3 mm

i did regap it to 0.65 mm

will turn it on again tomorrow

however, does anyone think this is the problem?

or any other suggestions?

thank you
i brought engine into garage, and

<br type="_moz" />

RE: evolution 50 cc gas engine troubles
 

Hi!
How does the engine behave without cowl?
Having a cowl with entrance and larger exhaust opening isn't enough, you must duct the air so it goes true the finns on the engine! That is very important!
What exhaust system do yoy use? I guess it's small silencer as the rpm is soo low (6400rpm wih a 23x8 prop).
In comparance my MVVS .45cc (Evolution in the US) turns a 24x8 Mentz prop at 6500rpm using the MVVS small cannister silencer.

How does the front ball bearing feel like? Do you have much play in the bearing?

RE: evolution 50 cc gas engine troubles
 

these are pics. do you believe maybe not enough air in?

RE: evolution 50 cc gas engine troubles
 

Hi!
With the cylindersticking out like that I see no problem with cooling. But what kind of silencer do you use? I recommend a cannister typ silencer like the one I showed above. Much more quiet than a small silencer and you get more power. I modified my Hi-Model Yak-54 so I could use the MVVS No 3206 cannister.

RE: evolution 50 cc gas engine troubles
 

wow
that is nice.

great job!!

so the cooling is not an issue


do you beleive the spark plug gap could be the problem?<br type="_moz" />

RE: evolution 50 cc gas engine troubles
 

Hi!
Could be!

RE: evolution 50 cc gas engine troubles
 

update

just got back from flying plane

engine did not stall this time.

flew plane for about 12 minutes

still had 1/3 tank of fuel left.

i did open up the LSNsome, and regapped the spark plug.

i will open up the cowl some more, just in case!!

RE: evolution 50 cc gas engine troubles
 

Can you snap a picture of the bottom of you cowl? You should have a bigger hole in the bottom them you have in the front. Hot air needs to get out. 1:1 is not enough, need more than that.

RE: evolution 50 cc gas engine troubles
 

i love your signature, BTW!

tell me what you think, should i open it up more

i appreciate your advice.

RE: evolution 50 cc gas engine troubles
 

Is that ignition rated for 8v? Most run fine on a 4 cell pack.

RE: evolution 50 cc gas engine troubles
 

This taken from the Horizon product description:</p><h3 added="null">Product Description</h3><h3 id="featureList" added="null">Key Features</h3><!tart FeatureLis><div class="wrapDiv" added="null"><ul added="null"> <li added="null">Phenomenal power in a 50cc package <li added="null">Field-proven, Li-Po-ready ignition system <li added="null">Rear intake design for higher power outputs <li added="null">Swings a 2-blade Mejzlik 23 x 8 at 6400 rpm using MTW cannister[/list]</div><p added="null">The owners manualsaysa 2 cell lypo battery for ignition is an optional item so I assume it can handle the voltage.

The Pamster
AMA 202345
</p>

RE: evolution 50 cc gas engine troubles
 

yes
i have the recommended lipo battery connected to it.

RE: evolution 50 cc gas engine troubles
 

I think your cooling is fine with the engine out there. I wouldn't cut anything. It sounds like you may have it all figured out, cool.

The Pamster
AMA 202345

RE: evolution 50 cc gas engine troubles
 

ok
great
thank you for looking at that.

this was flight 2 weekends ago:

http://www.youtube.com/watch?v=uJ66FHxURFg<br type="_moz"/>

RE: evolution 50 cc gas engine troubles
 

Check how you have your ignition module mounted. They all seem to require an air gap. If it is mounted flush to the motor box, (or wrapped 100% with foam) the ignition may be overheating causing the cutting out.
I have heard this from other pilots and have taken the time to mount the module on my DLA-32 with a 1/4" air gap and made a vibration isolating mount.

RE: evolution 50 cc gas engine troubles
 

Watching the video, nice landing btw, and reading the caption below it, the engine did sound rich. Unlike glow engines gas engine are not suppose to be tuned rich for breakin. That is accomplished by oil to gas ratios suggested by the manufacture.
A gas engine is to be tuned for max performance, i.e. set the hsn for max rpm then back off slightly, and lsn set for best throttle advance from idle.
A breakin period usually is a 24-32:1 oil mix  then switch to 40-50:1 oil mix after a specified amount of runs with the engine.</p>

RE: evolution 50 cc gas engine troubles
 

I will be interested to see all the suggestions in this thread. I have a DLE 55, 3 years old, which has run great until recently. Now it cuts out when the engine gets hot, with or without cowl, in air or on the ground. Runs great for about 3 minutes. Nothing has been changed recently. Cowl is baffled, ignition battery has good voltage and goes through a smart fly. Engine temp got to about 230-250F, as I recall. Thanks in advance.

RE: evolution 50 cc gas engine troubles
 

Hi!
My engine temp right after landing is around 100-110 degrees celsius meassured at the spark plug (20 degrees out side).

RE: evolution 50 cc gas engine troubles
 

Just a guess but I have been seeing ignition problems with the DLEs where they will allow the engine to start and run for a short while then die. Just something to give some thought to.

RE: evolution 50 cc gas engine troubles
 

I'm with Gray Beard. I'd look into the ignition for the problem.

RE: evolution 50 cc gas engine troubles
 

Thanks Gray Beard and darrolair, will order a new ignition and try that.

RE: evolution 50 cc gas engine troubles
 

I found it funny but one friend was having a problem with his 30, I put a new kit in the carb with the alcohol type diaphragm just because, I always go to the carb first with problems like this. It's cheap and easy so I just do the carb first. That didn't help so he took it to a friends home and I discovered several people I know have been keeping spare ignitions on hand?? When in stock they are cheap enough from Hobby King to keep on hand. When they said they were going to check the ignition I didn't know they were just going to install a completely new one. Worked like a charm. So far I haven't seen anything going wrong with the 55s but there are only a couple of the 55s at the field, must be a box car full of the 30s!!!:) If they are in stock at Hobby King they are worth the effort of buying, if on back order???? Your call!!:D

RE: evolution 50 cc gas engine troubles
 

Mike873,
PM BadAzzMaxx he is the "ignition" guru.

RE: evolution 50 cc gas engine troubles
 

Thanks darrolair, I sent him a PM.

RE: evolution 50 cc gas engine troubles
 

3 years no trouble then issues? I'd pull the carb apart and put a rebuild kit in, the local lawn mower shop here carries the kit for about 7 dollars including the little screen and new diaphrams and such.

Also make sure its got a good plug. I had one that was running a little ratty all the sudden and replaced the plug and it cleaned right up and visually the plug didn't look bad.