I am not the most experienced with the 2 stroke Gas engines. My only one is an old G23 in a Piper Cub - but I am comtemplating a total move to gassers only. My question is assume about the needle setting or the fuel mixture, or whatever could be is causing the excess mess. I am using Echo measured mix 50-1 and while my engine always runs well, I always have a bit of mess to clean off the bottom of my plane from front to rear. I thought that Gas engines made very little if any mess on the plane. Am it running it too rich? Any thoughts as I would love not claening my cub at the end of the day. Thanks.

sounds like you are on the rich side.


Its not that you never have to clean your planes with a gas engine... however it's not an every day thing by any means. Of course if you are anal about planes and how they look then you will probably want to clean the bottom real quick every day... but the build up is far less than glow could ever dream of.

it is hard to say from here.mine need wiping off after two or three days of flying but that is mine.it could be still too rich or the oil you are using.find a member of your club that flies gas and have them help you or turn the needles in just a very small amount and test it

Gas engine powered plane do need the odd wipe down now and then but it's usually not bad and not much beyond a bunch of little spots. I'd agree that you are probably a bit rich on one or both of the needles. Also petroleum based oils are more prone to this as well such as Lawnboy, Penzoil at 32:1 versus 50:1 and a few others.

Most synthetics will leave a little less residue.

Before you play with the needles, pull the plug out and try to either describe what it looks like or post a clear picture of it. Do this right after flying it, not just running it on the ground

On a well tuned engine, the ceramic part of the plug will be a medium to light colored tan, any darker then this and you are rich, lighter and you are lean. I'm betting on the plug being a very dark tan to black which is rich.

I would never play with the needles until I read what the plug has to tell me.

Thanks... maybe it is a bit of nothing.... next time to the field I will pull the cowl and do some test flying and check the plug after every flight. My next batch of gas will surely be full synthetic.

Why?

If it's running rich, the synthetic oil is going to get slung all over the plane too.

Check your plug and tune it if necessary. I'd bet it's rich.

Agreed and I'm sorry I forgot to mention that earlier. Read the plug, tune as needed and see what happens.

One thing about running synthetic in a gasser that is really good is that it will wipe off cleanly from the plane leaving no oily residue like glow fuel does.
Here is a very good web site to learn how to read plugs.

http://www.prme.nl/forum/viewtopic.php?t=10

Only way to prevent the oil spots is to get the exhaust as far from the prop as possible. #1 reason for using cans for me. If you get it to exit around the landing gear or farther back it will not need to be cleaned for many flights

While we usually look at the exhaust for residue, don't forget that the carb intake can also be a source of oil residue on the airframe. Piston ported engines tend to blow fuel (spit) out the carb at slow speeds or when opening the throttle quickly. You might investigate this as another possible source of your greasy bottom. Some people use velocity stacks to reduce this.