well i had another deadstick this past weekend and crashed her onto the soft grass. this was as i was climbing out from a touch and go and at about 25-35 ft the motor died. so i had no were to go but into trees so i decide the hell with that and i turned it downwind "very windy day" and landed....more like flew her into the tall soft grass....no damage just some grass stuck in the gears and prop. anyway my LHS guy told me to drop off my engine with him and he would take a look at it.... he calls me a few hours later and said that there was rust on the crankshaft...this is an os .61 fx..dose anyone know what could make this happen and what i can do to prevent this from happening again. i do use after run oil, so i dont understand why this happened. thanks guys

are you running the engine dry after the last flight of the day? what are you using as after run oil?

Hummmmm ... no question that the rust is a problem, but there is a big difference between a little bit of rust (discolorization) and enough rust to cause the engine to be prone to suddenly quitting in the air.
You did not say if this is a new problem or if you have been having difficulty for a while.
Did the engine ever run correctly ?
Did hobby shop guy say why / how the rust was causing the problem ?
What was / is his recommendation to fix it ?
If the engine is running good and idling good on the ground I suspect something other than rust is causing the problem.
The usual culprits come to mind ... cracked fuel lines, bad glow plug, needles not properly adjusted.

As to the rust issue, your location suggests a humid maybe even salty environment.
I use air tool oil on my engines, it is very good oil and it is pretty cheap too so you can use a lot of it.

i've had that happen to me and the reason was that i was running my engine to lean and when i was making a sudden turn or climb my engine would die. if your a rookie that could be a problem but experienced flyer, its not likely. i've been told by a number of guys that the red automatic transmission fluid is the best after run oil you can possibly use.

The rust within itself did not make the engine stop.

The reason is like Springhillflyer says

Hi 808_TITAN
I agree on the usual reasons for the engines to stop in theair. It is extremly rare for my engines to stop in the air. I tune ithem to always be a little rich. I get a little less power but more reliability. I frequently change ALL of the fuel lines. I always have extra glow plugs on hand. I have been flying since 1972 and have never used after running oil. It has been close to 30 years since I took one of my engines apart so I don't know if they are rusting inside. I have engines that I run about weekly that are 10 years old. All are OS 46 FX or FA. I have wanted to see more evidence of wear so that I would at least have a reason to replace them. Hope some of this can help you.

In the long run the rust is going to be detrimental to your engine in the long run.

The rust particles will go up through the cylinder and damage all of the engine eventually.

You should get the bearings replaced and the rust cleaned out of the engine.

The bearings are what rust first and are more rusty than the back side of the counter weight that you see.

Soon the engine will start sounding like a thrashing machine with all kinds of noise.

Might be worth taking a look at your fuel.

Methanol is hygroscopic (absorbs water from the air). Water in the fuel could separately account for both your deadsticks and the rust.

Just a thought

Terry

Fuel that has been in the sun a lot will not run reliably and the engine will quit on you at the most inopportune times

well the engine ran fine up until i started using the after-run oil. at the end of anyday that i have been running my engine i allways run it dry. as far as the erratic manuvers before the deadstick i was doing a smooth climbout from a touch and go so im sure that wasnt it. my fuel is about a month old. i noticed that when i would dry crank my engine to prime it, on the first one after sitting for the week allot of times it would feel stuck. and that kinda worried me. my lhjs guy took it apart and found the rust. he cleaned it up and we will see what happens this weekend when i fly weather permiting and if i still have this cold that i have. glowplugs i have burnt out one so far and have about six in my flight box....thanks for all your suggestions....anyway to know if my fuel is no good anymore? thanks again guys

Keep an ear on the sound of your engine. If it starts making a whirring noise or any unusual noise, take it to your man that works on your engines.

Happy flying,

Jim

I'd guess that 90% of flame outs are needle problems. Either the high-speed is set too lean, or the low-speed is out of adjustment one way or the other.