H E L P ! I DO NOT HAVE A CLUE !

[Paul Taylor]

So I went to run my OS FP 40 today in hopes of flying this weekend. This is a new setup for me.
This is my full body stunter with an inverted engine.
I try and flip the prop over and it will not go. Fuel is pouring out the vent. I figured the head is full of fuel. I pull the plug and fuel poured out and also every other hole in the engine. Vent and Muffler.

I am using a clunk tank, with muffler presure and the fill tube capped.
How am I getting a case full of fuel?

[John Paris]

Paul,
If you have your tank plumbed for standard flow, then with the height of the fuel being above the spray bar assembly, I would guess that the fuel is just draining down into the engine.  To keep this from happening with your current plumbing, I suppose you could keep the nose real high until you are ready to start or use some hemostats to pinch off the line until you are ready to flip.  The thing that bugs me about this is that with an inverted mounted engine, the fuel should just run out the venturi on to the ground. 

If you have your tank plumbed for uniflow, you could be siphoning the fuel from the tank down to the muffler and maybe into the cylinder from there.  After looking at the muffler on your airplane though, I am not too sure that this is what is happening.  It could also be that you are siphoning to the venturi as I cannot see the routing of the pressure line to the muffler.  In general, the fuel will go to the lowest point and start siphoning there.

Best bet is to keep the nose high until you are ready to flip, pinch off the line going to the spray bar and to give the airplane a tip towards the muffler and a couple flips to clear the cylinder prior to starting.

Best of luck and let us know how it works out.
John

[Leo Mehl]

So I went to run my OS FP 40 today in hopes of flying this weekend. This is a new setup for me.
This is my full body stunter with an inverted engine.
I try and flip the prop over and it will not go. Fuel is pouring out the vent. I figured the head is full of fuel. I pull the plug and fuel poured out and also every other hole in the engine. Vent and Muffler.

I am using a clunk tank, with muffler presure and the fill tube capped.
How am I getting a case full of fuel?

I would take the tank out and make sure you have the tank plummed right. Another thing that might help is run the tank on straight draw. I am not an expert when it comes to clunk tanks but i do know it easy to get the lines mixed up if you don't mark them.

[Wynn Robins]

as the others have said - check the plumbing

If there is that mcuh fuel in there, then it will be coming in through the mufffler

I use clunk tanks on muffler pressure pretty much exclusivley - make sure the Muffler pressure tube goes to the top of the tank - just the same as your overflow tube.....

I put mine right next to each other RIGHT AT THE TOP of the tank....this eliminates syphoning.

PM Me for a drawing

[Leo Mehl]

as the others have said - check the plumbing

If there is that mcuh fuel in there, then it will be coming in through the mufffler

I use clunk tanks on muffler pressure pretty much exclusivley - make sure the Muffler pressure tube goes to the top of the tank - just the same as your overflow tube.....

I put mine right next to each other RIGHT AT THE TOP of the tank....this eliminates syphoning.

PM Me for a drawing

Thanks,I needed to know that myself.

[Alan Hahn]

Think about it for a second. If the fuel was siphoning to the spraybar, it would simply flow in and out the bottom onto the ground---there wouldn't be anything in the engine at all.

So for some reason your fuel is being put into the muffler, and then flows into the cylinder. My guess is you are filling the tank and the overflow is going into the muffler.

[Randy Powell]

Didn't fuel it with the overflow capped, did you?

[Wynn Robins]

hey Leo - No problem - here to help! 

[Wynn Robins]

Didn't fuel it with the overflow capped, did you?

good point randy!

Although - to eliminate this scenario - I always fill through the muffler pressure tube - make sure the piston has the venrturi blocked, this way, if you have the vent capped - you will find out sure enough that it is as the fill tube will blow back off covering you in fuel.....ask me how I know!!!!!   glow fuel tastes BAD!!!

[john e. holliday]

I had to taake an attempt in first round of Old Time at VSC this year as my set up started flowing fuel into the muffler.  Same set up I had been practicing with.  Removed the muffler pressure and put in my first round flight of 9 minutes and 39 seconds.  Of course I was running muffler pressure to the uni-flo line.  DOC Holliday

[Paul Taylor]

OK, I think I know what went wrong. I had about a half of tank when I hung the plane on the wall. NOSE DOWN. 

I still have some type of fuel problem. I tried for over an hour to get this thing running and no go. I am going to pull the engine out an put it back on the test stand.

[Jim Thomerson]

I presume you fill through the muffler line, with the overflow cap off.  Put the overflow cap on, then take your syringe off and reattach the muffler line. If the muffler line is reattached first, it will start siphoning when you put the overflow cap on.  Been there, done that.   

[Doug Moon]

First off never hang up or store a plane with fuel in the tank.  Changes in the temp will will cause that air to expand and it will leak out eventually and ruin anything it drips on. 

I as others have stated use muffler pressure as well. 

I also make sure to fill into the pressure line of the tank with the over flow cap off. 

I then cap the over flow line and never hook up the pressure line until I am ready to start the plane.  This leaves and open vent for air to escape from.  Do this on hot days for sure or if you are flying back to back flights.  If you button up the system and let it sit there hot air in the tank will expand and push the fuel into he motor.  Been there done that about a bagillion times.  Just put the pressure line on at the last minute and the prime the motor.  And start it.

FPs Flood very easy when inverted.  You will only need one or two primes, cover venturi with thumb and slowly roll over the motor and that should be enough.  Start flipping.  It is better to be flipping a little lean and work your way into a good repeatable prime sequence then to be working from a flooded start. 

Flooded FPs can take a long time to start.  Best to take the plug out and spin it over a few times reinsert plug and flip the plane over for an upright start and try inverted next time.  When starting hot, right after a flight, just fill it and hook up the battery and flip it to start with NO prime and it should go right off.  If you prime hot it will flood and then you are up a creek again.  When I was running FPs for my main motor my prime was something like roll over with thumb over venturi 2 times then flip it through like starting 3 or 4 times then roll over with venturi covered 1 more time then hook up battery and flip and it usually hit on the first or second flip every time.  I hope this helps.

[Paul Taylor]

Thanks guys lesson learned on storing the plane with a little fuel in the tank.

Now I pulled the engine from the plane and the tank. I did have all the right lines going to the right places. I put the tank and engine in my test stand to run it there. Engine will not start. It will run a prime out and then nothing. Like it's flooded. No bump, or thump. And I have a good plug. I am using my flite box battery.

I have never had problems with my LA's. One or two flip starts.

Hmmmmm

Paul 

[john e. holliday]

Did you put the engine on the test stand while it was out of the plane?  If it is back in the plane I would disconnect the muffler pressure line and flip the plane over to start the engine upright.  Also have you checked the hole in the spray bar?  My "13" is now flying with no muffler pressure as I must have a small leak somewhere letting the fuel flow into the muffler.  Let us know,  DOC Holliday

[Doug Moon]

Thanks guys lesson learned on storing the plane with a little fuel in the tank.

Now I pulled the engine from the plane and the tank. I did have all the right lines going to the right places. I put the tank and engine in my test stand to run it there. Engine will not start. It will run a prime out and then nothing. Like it's flooded. No bump, or thump. And I have a good plug. I am using my flite box battery.

I have never had problems with my LA's. One or two flip starts.

Hmmmmm

Paul 

If it runs the prime out and then nothing it is not flooded.  It just burning off your prime and cant pull fuel for some reason.  Are you priming with bottle or rolling over the prop with venturi covered?

Sounds like an air leak somewhere, tank, or split tubing.

Do you run filter?

Give us details on your setup, tank and stuff.  Details on your procedure.

[Alan Hahn]

Take out the needle and look thru the spraybar. Make sure it isn't full of gunk.

Do you prime by choking the intake?--I ask because that at least is a sign that you can pull fuel into the engine. I also assume you have played with the needle.