pauluk2w

My Feedback: (7)

i have a hanger9 xtra easy with an MDS .40 engine and a P51 mustang with an OS90 4 stroke engine. should i use an after run oil in these engines, what is after run oil for, and how do i use it.

flyinrog

My Feedback: (1)

its a personal thing some people use it religiously,,others (like me) have never used it..if you leave raw fuel in the plane the methanol will attract moisture, but there is already 18-20%oil content in the fuel too......run it out of fuel after you drain the tank ,,ask others, use it if you want,,probably a good idea if you only fly 1 time a month.....Rog

DBCherry

My Feedback: (4)

I used it when I first started, then stopped after a year or so. Those same engines are all running fine after 8 years.

I DO use some oil in them when they will be sitting for mare than a few weeks though.

Whether or not you use it is up to you, it certainly can't hurt anything to use it, and there's debate as to whether or not neglecting to use it hurts.
Dennis-

Woody 51

I only use it in 4 strokes after each flying session, or in 2 stroke engines that I am going to put into storage for a while.

If you disconnect the fuel line from a 2 stroke at the end of a flying day, and then start the engine to get rid of any fuel still in the carby /combusution chamber, after run oil really isn't neccessary on an engine that will be used again in a short time span.

It's hard to get all the gunk out of a 4 stroke due to their lower operating temps, so I figure that a little after run oil is insurance against bearing corrision (and the fiddly job of dismantling the engine to replace them) in a 4 stroker.

Tom Nied

If you want to make your own, try this recipe.

1/2 Marvel Mystery Air Tool oil to 1/2 Automatic Transmission Fluid, put in a handy applicator bottle.

Do you need it? Maybe not. Will it protect parts from rusting, you bet.

photoniq

to be honest it is not that expensive and it lasts for ages. I can not see any reason to NOT use it (unless your engine specifies not to use it - don't YS engines have that?). It makes me feel better to use it since I keep my planes in the garage...
P.

Rodney

Your climate and storage area determine how much is needed. If you are in a moist climate, I'd recommend it, especially on 4 strokes. You can not run the fuel out of a 4 stroke crankcase so you will most probably benefit by using after run oil in them. Not just a drop or two, you need to inject at least a teaspoon full into the crankcase vent and turn turn the engine over by hand a few times with it positionedto get the sil around the bearings and con rod. A good and inexpensive after run oil is Rislone (in the yellow container) which is available in most discount stores and auto parts stores. If you are running a fuel with castor oil in it, the need for after run oil is somewhat less than if you are running synthetic oils only. Put it this way, after run oil certainly won't hurt and will most probably help to keep rust out of the bearings.

Geistware

My Feedback: (16)

If you are using fuel with full synthetic oil, then I would say no.

Mad Mad Max

What kind of bottle do you guys use to apply oil to a 4 stroke? I have been using a small plastic bottle that I got from a drug store and fuel tubing to reach the carb intake, but need a better solution.

ifixairplanes

My Feedback: (9)

i use it every time i fly! Why risk getting nasty, gritty, grindy, rist in your engine when for about $10 a gallon, you can use marvel mystery oil and make sure it dosnt rust. why risk it. if you got the money to replace piston, sleeve, bearings, then dont use it. the main question is: why not use it? like said above, cheap insurance. I have an OS 4 stroke, after a day of flying i squirt a good amount into the crank case and then into glow plug holes. i also pull off my rocker cover, and squirt some on my valves, rockers, and down the pushrod tubes. A little extensive? maybe, but i can guarantee my engine is not going to have a spot of rust in it.

FYI: i just recently took apart a 1 year old .46FX i had, it was stored for 4-5 months in a plastic bag. because i always use after run oil, and i "pickled" it before i stored it, everything inside was shiny like new. i only had to clean the carbon off of the cylinder head and top of the piston.
Do your engine a favor, feed it after run oil. it provides you with hours of enjoyment, so why not give it a little care?

sean

FLYBOY

My Feedback: (11)

Gotta tell you the same thing I tell everyone that asks this. No after run oil.

For over 27 years, I fly, when I am done, drain the tank, don't run the fuel out and have never had a problem. Every one of my friends that run the fuel out and use it replace bearings about every 2 years. There are some reasons for it that my full scale mechanic explained to me, but the short of it is running the fuel out does more harm that good. The nitro evaporates very quickly in a hot engine, leaving just the oil. That is all the lube you need.

If you are going to store it for any leangth of time, then use the oil mix as stated above, or what I do is just fill it with marvel mystery oil. Never had an engine go bad and never replaced a bearing.

It is your choice though.

DTB

My Feedback: (15)

I only use after run oil in brand new motors that have never been ran by me. I drop about 8 drops through the plug opening and turn the shaft to get it worked in, then start the motor. This pre-lubs the engine before it is ran for the first time.

I have O.S. and Y.S. engines and never use the stuff. I run dry, but I live in Jackson, Mississippi and it is flying season year round here so the engine never sets for over a week without running. If I was to set an engine up for an extended period of time, I would use after run oil just as a precautionary factor.

If the engine is ran dry and no fuel is left inside, how can it rust? That would be the best possible situation, but in the real world, some residue of fuel is going to remain there even if the engine stopped running. If this residue sets for an extended amount of time it will attract moisture (H2O) that will cause rust, but the amount of rust may be so small that it isn't causing a problem and once the engine is ran, that small rust will be destroyed. The engine's Ball Bearing may have a very very very small pit, but it isn't causing a problem and would not be noticed.

Setting still for more than a 1 month, use after run. It won't hurt.
If setting under 1 month, it isn't mandatory.

Again here in MS, we fly year round and the engine doesn't set up for long.

bulletbob

I had an older Magnum which stated not to use after run oil in it so I would check the owners manual.

DTB

My Feedback: (15)

I read somewhere once not to use After run oil in a YS due to the regulator clogging up or something to that fact. I also heard not to use it on the FX series by O.S. also. Can't remember the exact reason, but I saw it somewhere in a reading. Not sure how true it was.

jerry0

If I am going to use the engine within a week or so, while the engine is hot, I simply disconnect the fuel line, put on the glow driver and turn it over with the starter for two to three seconds. This removes any fuel that is inside the engine. The culprit is the nitromethane in the fuel that changes to nitric acid when combined with water. The humidity in the air will mix with any nitro in the crancase and the resulting acid will cause the bearings (and other steel) to rust.

If you are not going to use the engine soon, do the above described procedure, then add some oil(I use transmission fluid) in the carburetor and flip the prop over several times. Repeat once. This will protect the innards for a long time.

On 4strokes, I put a small (1-2 cc) oil into the crancase vent as the fuel going into a 4stroke doesn't go thru the crancase. Flip the prop a few times and it will be set to set for a while.

dreadnaut

My Feedback: (5)

After run oil should never be used on Y.S. engines. They all have a pump that presurizes the fuel tank. The presure regulator has a silicone diphragm that will be disolved by after run. I have a couple of Y.S. engines and have gotten in the habit of just running ALL of my engines dry.