DrJones

I was at the field yesterday and everything was going fine until I wasn't paying much attention to flight time and ran out of gas. Not too big of a deal....I've had plenty of deadsticks. Well I had to put it down in a field and it took a little tumble.When I went to pick it up there was dirt/sand on the engine. The carb was full open when it hit and there was a little sand around the inside of the opening but from what I could tell, there wasn't any inside the carb itself. If some sand did get inside the carb, what steps should I take to clean it. Also, what can happen if the sand goes through the engine.

Help is appreciated....I'd rather not have to buy another engine because of a little dirt.

Thanks

big max 1935

My Feedback: (9)

Doc: I would remove the engine & then remove the rear cover & glow plug . I would flush it with hot water (cheap) & then some glow fuel (cheap also). Put it back together & back in plane & run it. All the junk right now is in the crankcase bottom & if you run it kiss it good bye. Next! MAX H.

dickj

My Feedback: (1)

Heres how I do it. I go to the local auto supply store and buy a can of brakleen cleaner. Use your rubber glove and hold the airplane with the tail in the air, the carb inlet open to you and spray the brakleen cleaner in and flush this motor out. I do not take the motor apart but have on occaision if dirt appears inside the carb removed the carb and cleaned both separately. I just did this yesteday as a matter of fact. Works for me------

PS: I learned this trick from my Hobbytown RC Instructor nine years ago in Mesa, AZ.

majortom-RCU

My Feedback: (40)

First rule is, don't crank it over. Don't turn the prop any more than you can help.

Use kerosene or glow fuel for cleaning/flushing. Collect a stiff bristle brush (epoxy brush will do); Q-tips; toothpicks; paper towels; light oil (air tool oil, Marvel Mystery oil from auto parts store or after-run oil from hobby shop); plastic container to hold cleaning fluid (kero or glow fuel); fuel bulb or syringe for flushing; hex-drivers; pliers; screwdrivers; prop wrench; glow plug wrench; inspection light; hot-air blow gun. Clear bench or counter top.

Remove engine from mount. Shake, brush and gently pick loose as much dirt as will readily come off and out of the intake. With brush and cleaning fluid, brush the exterior clean.

Remove the muffler. Remove the carburetor. Clean the carburetor by dunking in cleaning fluid and brushing/picking. Open the throttle wide and hold the opening up to a light. Everything should be clear and smooth. Q-tip any specks out of the throat.

Now look down the carburetor opening in the crankcase. See whether the rotary valve is shut, partially open or fully open. If it's shut or partly open, then flush and Q-tip clean.

Remove the backplate from the crankcase. If there's a gasket, try to get it off in one piece (or get a replacement, or get a tube of Permatex Ultra Copper sealant from the auto parts store and lay a bead of that down in lieu of a gasket when you put backplate back on). Some engines use an O-ring, some nothing at all on the backplate.

Remove the prop and cylinder head.

With backplate, head and carb removed, turn the crankshaft so that the rotary valve is fully open. Flush cleaning fluid down the intake, through the rotary valve and drain out the backplate opening.

Next, dunk the open crankcase in the cleaning fluid, agitate gently and drain.

Use Q-tips to touch out any foreign matter that you see. Shine your inspection light through the backplate opening and look down into the open rotary valve. Then shine your inspection light down the air intake and look through the back of the crankcase.

Next, with piston at its bottom rotation, flush the upper cylinder, letting the fluid drain down through the intake ports and into the lower crankcase, draining out the backplate opening, to flush out any dirt that may have worked its way up the intake ports.

Now turn your crankshaft gently, feeling for any resistance suggesting grit in the bearings. Probably there will be none. If you sense any roughness, then you need to completely disassemble, inspect and probably replace bearings. If not, wipe the engine dry on the outside, put the prop back on (to use as a handle), and give it a thorough drying with the hot-air gun blowing into the exhaust port and down the open carb hole with fully open rotary valve.

Now drip a few drops of oil around the top edge of the piston, ten drops or so down the air intake, ten more through the backplate opening around the edges of the crank rotor so it will run behind there and into the bearings/bushings.

Replace backplate, cylinder head, muffler. Maybe also put in a new glow plug. Flip the prop, see how it feels. If it feels good, mount it, run it, fly it. If not, see your physician.

I have the Dave Gierke book on glow engine maintenance and repair (from Model Airplane News, I believe). I read it some time ago and liked it. If I had more time, I'd dig it out and refer to it. I hope there are no glaring discrepancies between this procedure and Dave's book. This ingested dirt business comes up more often than one might expect, so it's good to have everything in order to do this when necessary.

I've quite possibly overlooked some points, pulling all this off the top of my head, so I hope others will tell us how they do it.

big max 1935

My Feedback: (9)

Whew ! Aren't you lucky I was first ! MAX H.