gregoryshock

Two years ago, I built a plane that required the Engine mounted inverted. Right away I began having problems. So I did some online searches, and discovered that many modelers don't like inverted engines. (I don't like them either but sometimes you don't have a choice) My biggest issue is starting. It seems that after the engine sits over night, the oil in the fuel all gathers onto the glow plug, causing a hydro lock. To make matters worse, It's very hard to reach the glow plug through the cowling. I've been using a socket with an extension to remove the glow plug, and using a starter to spin the engine over. Then I must use the extension to put the glow plug back in. The other day, I nearly stripped the head treads! Is there anyway to keep the left over fuel oil from collecting on the glow plug?

The Engine is a 61 OS two stroke.

Gray Beard

My Feedback: (-1)

Try running the engine and tank dry at the end of the day. There shouldn't be enough oil/fuel left in the engine to lock it up. That is usually a sign the tank isn't empty and is mounted too high then siphoning back into the engine. I make up a remote glow driver using parts from Radio shack and I think Dave Brown or Cermark glow plug caps. They look like small spark plug boots/caps. The parts from radio Shack are just male and female mono head phone jacks. Very simple or you can buy the remote glow drivers from most any hobby shop. I just don'e care for the store bought units, they tend to fall apart over time.

gregoryshock

I suck out the tank at the end of each flight. I also Start the engine up, and allow it to run the carburetor dry. The oil on the plug looks very thick, not like wet fresh fuel! It doesn't feel cold either.

Gray Beard

My Feedback: (-1)

I'm just shooting guesses here but usually any oil that finds it way into the head after a dry run isn't very much and usually looks very fresh. I just haven't ever seen enough oil left behind to lock up an engine? The one and only two stroke engine I had lock up on me was full of fuel, the engine is mounted upright too?? I have never figured out how I did it but it had to be something I did? It only happened once.It's just a guess but it sounds like you aren't getting all the fuel out of the tank?? If the plane is stored nose down then any fuel left in the back of the case can drain into the head. On a plane with a vapor locked engine you usually can hold the plane nose up and rotate it so the fuel will drain out of the muffler and it clears it. If you can see your fuel tank then you can drain it then see if you are leaving fuel in the tank. I have a couple I have to hold nose up a couple inches to get all the fuel out of the tank even after doing a drain and run.

gregoryshock

Gray Beard.  Thank you for your reply....

I have thought maybe it's my starter?  Cause I have an engine that is mounted right side up, and that starter has a hard time turning it over.  But after the engine gets started, and warmed up.  The the starter turns it over just fine!   I know it's hard to describe on the internet.  But just how hard should an engine turn over.  I'm just trying to figure out what are the signs that a starter is going bad?

ARUP

I don't think it's your starter if the engine turns over easier when the engine is warm. That's just a property of the non- ringed engine you are using. They are designed to be a tight fit at the top of the stroke. Don't overly lean that type of engine or the fit will be ruined if that's what kind it is. You may have a slightly low starter battery, too.

pimmnz

Hang the airplane from the prop whenever you are not actually flying. That way any fuel/oil residue will drain to the backplate, away from the plug and the bearings. The stuff can't do any harm there.
Evan, WB #12.

LesUyeda

I hang mine by the tail, and wrap a paper towel around the thrust washer to catch the drippy oil, before it gets all over the wife's windshield:-))))))))))))))

Les

JohnBuckner

My Feedback: (1)

Gregory what you are experiancing is hydrolock not from fuel but left over unburnt combustion products that normally collect in the muffler. This material does tend to collect there and in an upright or sideways mount set up it is not a problem save for the time you may pick up the airplane carelessly nose high after a run and this oil like gunk will run out on your arm from the muffler outlet.

What is happening with your full inverted mount is either you or someone else may pickup the airplane nose down after a flight or just loading in the lorry. This heavy liquid that has collected in the muffler will flow directly into the combustion chamber if the prop is in the right position and it will remain their untill the next time you try to start.

This muffler gunk loading of the engine during post flight handling is often confused with fuel loading of the engine from a poor fuel tank height setup and the subsiquient possible syphon effects but this is really a different problem. However both have the same effect and that is hydrolocking.

The simple expediant of always carrying the airplane nose up will greatly reduce this problem and instructing anyone who may pick the airplane up to do the same.

With an inverted mount glow engine clearing by plug removal and spinning should always be the first step when any kind of hydrolock is suspected and for that reason I recommend not using an on board plug driver.

John

Gray Beard

My Feedback: (-1)

Thank you John. After reading that I should have known when he mentioned the color of the oil. Another senior moment. A little something about vapor lock. I don't have the problem but I have gotten in the habit of rolling over all my engines by hand before I touch them to my electric starter. Sense I started using the Harbor Freight 18 volt battery like John, making sure the engine will roll over is a must. If I had a lock up and used the starter I would be bending and breaking some of my favorite parts.

cap10b

Really go gas and forget all that glow mess.
Hello DLE20
Jds