Hi,

I'm running a OS 46LA, in a Extra 300L, and the engine is inverted. But when ever I roll inverted the engine splutters and dies[:@].

This doesn't make sense to me, as the engine would then be running right way up.

I'm getting some new plugs, but any other ideas???

Also, I'm having trouble starting it consistly[], any tips for inverted engines starting???


John Murray

Your tank is too high

Enjoy,

Jim

Inverted engines needs a very proper priming to start manually.Be sure of having a good charged,powerful glow driver battery.Be careful about the residue exhaust oil reservoir just mouth of the muffler pressure nipple not to cut pressurizing tank when static running(on ground)

If that were my plane and engine I would make several changes. Go to a 10x6 prop, preferalbly an APC. Take out the exhaust baffle. Run a idle bar plug. If the engine is new give if a few runs to break in. You may need to tune differently (leaner) when moving from upright to inverted.

In addition to the other posts, have a close look at the whereabouts of the muffler pressure connection. If oil can collect in there, your engine will die. You may need to move the location to the exhaust stack.

In all fairness however, I think your tank centre height is way out of line with your carb spray bar location.

Hi!
Have you checked your tank position?!
Center of tank should be inline with center of fuel intake orifice in carb when airplane sits horizontal. Simple as that!
It could also be a leak somewhere in your tank set up , in conjunction with too large tank and long fuel lines and vibration leading to fuel foaming in tank.
Wrong glowplug, fuel and so on...everything is depending on everything else!
This is what I would do...
Fuel: 5-10% nitro, No more is needed.
20% castor oil or synthetic oil or a mix....in Europe 15% all synthetic oil like Motul "Micro" from France.
Glowplug Enya 3 or OS 8, these are two of the best sport glowplugs available.
Tank: 8-10oz tank...not more! The best tank however is the Tettra "Bubble-less" fuel tank from
Dave Shadel (Y&S US importer).
Tank should be close to the firewall with as short fuellines as possible.
I would recommend using a two clunk set up (a Uni-flow set up) , one line going to pressure nipple on silencer and one to carb, You also have a third line for fuel overflow, totall 3 fuel lines.
This is a more reliable tank system than an ordinary tank set-up.
Fueltank must be protected in soft foam...not placed directly onto wood surfaces in fuselage (like on most ARF airplanes).
Propeller: 11x6 for general sport flying. APC is one of the best.

Regards!
Jan K
Sweden

I've noticed this happens sometimes with this engine if the bottom end is set just a LITTLE too lean [ie the screw is too far in]. Might be worth checking for this easily remedied problem first, just in case? If it turns out not to be the problem, then follow the good advice, above.

Good luck!