carl24bpool

Hey guys.

I recently crashed my trainer so I'm just dusting off an old low wing seagull space walker that I bought second hand.

The engine is mounted upside down behind a cowel. I seem to be struggling starting it. I've stripped and replaced the entire file lines and still no joy.
Pis there anything different I should be doing to run it?

if I prime the engine it will run but then cuts as if the fuel isn't getting through. If I blow down the line connected to the muffler it will come easily from the carb line so I'm a bit baffled.

Is there anything obvious I'm missing? If not ill just keep trying.

DavidAgar

My Feedback: (108)

Upside down engines can be hard to deal with. They are easy to flood and cool of the plug. I would turn the plane upside down and give it a try. You would want to also make sure that the fuel line into the carb is level with the fuel tank pickup. Good Luck, Dave

carl24bpool

I have had problems with flooding. If I turn it upside down to start it then fuel comes down the muffler tube and fills the muffler.

i also don't have any means of safely holding it upside down.

jester_s1

If it's flooding you should be able to get it to run full throttle. It's idling where siphoning fuel causes a problem. What you are describing sounds like a an obstructed fuel passage, probably at the spraybar. Option 2 would be an air leak either at an oring, fuel line, or the engine backplate. Try replacing all the orings (good practice to do it annually anyway) and if that doesn't help, soak the carb in fuel for about a week to dissolve any varnish in those small passages. If you will pump some fuel through the carb nipple through the spraybar a few times during that process it will help blow out anything that's in there.

carl24bpool

I found there was a leak from the needle valve. It was coming out from under the screw in bit. Upon inspection there epwas no o ring but also I couldn't see a ridge where one would sit. So I cut some silicone tubing which compresses when it's set about right. Ill try and find a manual and check if there should be an o ring on an Irvine 40. It's an old Irvine as I've had it over 15 years and was second hand when I bought it.

I got it running and it runs great with loads of power.

These upside down engines are a nightmare though. When I fill it I have to close off the needle valve totally to stop flooding. Not ideal. Otherwise the cylinder totally floods preventing you from turning the prop at all.

I need to get used t a way if working with it. The fact it's a low wing also means its hard to see when the tank is full. I always end up getting fuel in the muffler. I guess I should take the pipe off the muffler but its all a lot of messing about if you ask me.

it was all however worth it as my first ever flight with a low wing was wonderful.

ill update my diary with a report but first my girlfriend is demanding one of my foot rubs. Back shortly.

opjose

I run almost all of my 40+ engines upside down ( inverted ), both gassers and glow...

Those who claim there are problems doing so, don't know how to tune or set up their planes/engines.

Inverted glow engines do have a SLIGHT tendancy to pool fuel in the glow plug, but this normally happens when the engine is new and thereby out of tune.

Once the engine is properly tuned, fuel has less of a tendancy to flood the head with the needles properly adjusted and the throttle at idle.

An inverted engine has a slightly tighter tuning window, but this is not a big deal. If anything you'll get better at setting up your engines than most.

Just remember that you normally do not need to prime an inverted engine prior to starting and you'll do fine.

Fuel tank height only affects the engine when the plane is sitting on the ground with the engine off. Fuel can siphon into the plug, but if you keep the throttle fully closed before starting that will stop or minimize. Once running your engine should not care if it is upright nor inverted.

carl24bpool

Oppose you sound like you know the script.

can you offer tips on the starting procedure?

if I fill the tank down my filler pipe how do I know it's full without filing my muffler with fuel? That fuel then floods the head and locks the engine until I invert the plane and pump it out.

opjose

On most of my inverted glow engines I have the muffler below the engine head. When I fuel the plane excess fuel runs out the muffler. On a few I remove the pressure line while fueling. You can use different fittings or routing to help you eliminate the chance of hydro-locking the engine with excess fuel.

Also I always disconnect the fuel supply to the carb by using a fueling fitting that does this. You don't need anything complex or elaborate for this.

I like the World Model's fillers...



As far as setting up the plane, here is a tip.

Get the engine running upright, even if you have to flip the plane over initially. Leave the glow plug on and get the engine idling.
.
Turn the plane upright ( engine inverted ) then remove and re-install the glow plug igniter. Listen for ANY DECREASE in RPM's as you do this.
If RPM's decrease when you remove the glow lean the engine and try again.

Set the idle speed screws so that removing the igniter results in no change at all. You'll find that this will give you a reliable idle and the engine will not bog down over time.

Double check your high speed needle with a nose up down test, and have at it.

j.duncker

My Feedback: (2)

If you choose to start the engine inverted AND use an electric starter I would always turn the engine over by hand a couple of times to make sure it is not 'hydraulic locked' by being full of fuel.

It is a good habit to get into with all engines regardless of orientation. As you get used to the 'feel' of each one you can tell if it is dry, flooded or ready to start. If you have the glowplug energised and feel the 'bump' it is ready to go. Wear a thick leather glove !

Dansy

My Feedback: (53)

Since you mention that you bought it used not sure if its a old old model....while the fuel line replacement was a good idea did you open the fuel tank and replace that line....look at the clunk if its a brass one it might be corroded from the nitro....

running engine upside down is no different the upright......you can still flood an upright engine and lock it! If you really have problems my suggestion would be to mount the engine on a test stand and adjusted since you seem to be a new flyer, that make thing just a lot easier.

Indy Park Flyer

A friend of mine installed one of the fuel fillers from The World Models on my Seagull PC-9 with an inverted Thunder Tiger Pro .46 this afternoon, and the difference was night and day. The engine didn't flood when I fueled it, and it started without a problem. We did change my fuel set up from a 3-line to a 2-line tank, Here is a link to the fuel fillers http://ecsvr.com/twm/ShopDisplayproducts.asp?Search=Yes.

carl24bpool

Thanks for all the replies guys.

I was out with it last night and I kept the throttle closed when filling and took the muffler pipe off and it worked great. I didn;t prime it either.

I did get an issue where the glow plug was submerged which made starting harder but I just turned up the current on the glow starter and it seemed to burn it off quite quickly.

acdii

DLE 20 runs great upside down. Looking forward to see how the YS 110 runs upside down. Probably not very well at all.

opjose

Yup, it's just a matter of adjusting the "pilot" not the engine.

Neither glow or gas engines care whether they are upright or inverted, particularly once they are running.

Anyone who says otherwise just needs a bit of training.

carl24bpool

Thanks again.

One issue I did get was that it was difficult to start with the starter motor. The glow starter current was showing 1.5 (volts or amps?) on hte needle and nothing would happen. I turned it up and it started.

On the same issue of glow plugs I blew 2 enya 3's the other week. Both times I wasn't much above 1.5 on the dial for the starter. Are enya plugs prone to blowing or something? I heard they were the best to use?

opjose

Careful!

You may be drowning the glow plug with fuel, and by turning up the voltage you are burning up the fuel that is pooling.

In effect, you are compensating for an improper starting proceedure by turning up the voltage.

Check your glow plug by directly connecting it to the voltage source while it is out of the engine. Does it glow at 1.2 volts?
Glow plugs are supposed to be used with LESS than 1.5 volts... they were designed with 1.2 volts in mind.

Instead, try fueling in such a matter that no fuel is pushed into the carb. Then do NO priming.
Attach the ignitor, and keep turning the engine over with the electric starter until it starts up.


It could be you are using too high of a voltage, or it could be that the engine is new, or the high end is a bit too lean.

On a new engine small particles slough off as the engine wears in, and coat or affix to the glow element. This greatly reduces it's lifespan.

On some new engines I'll get a few flights on the engine, then the glow plug will burn out, or idle will be adversely affected.

Replacing the glow plug cures the idle problems, and typically after the first or second plug, subsequent plugs seems to last forever.