Fuel stopping my engine turning?

[Extensa]

Hi I have been experiencing problems with my starter not being able to turn my Os 50 engine over. I removed my exhaust and tipped it over with tissue to catch all the thick fuel coming out of the Carb, after all the fuel was out of the engine it turned over every time really smooth. I'm using Optifuel 30% Nitro is this too high a percentage? As it seems too thick which is creating a vacuum in the chamber which is stopping the engine turning. I'm using the Align starter with a 2200mAh LiPO battery so I think that is fine for a 50cc engine?

Thanks, Mike.

[jimmyhorns]

You are experiencing what sounds like a hydro locked engine.

This happens when fuel fills the combustion chamber, and then when under compression it has no where to go (as fluids are not compressable). Continuing to try and crank your engine over can do considerable damage in this situation, as something will have to give at some point, and this probably wont be the fuel!

This is probably happening as a result of your fuel being siphoned into the chamber after a flight, and can be stopped by clipping off the fuel supply after each flight (I have to do this on my OS 50)

If this happens, the easiest way to get the fuel out is to remove the glow plug and let the fuel out. Give it a few blasts with the starter with the plug out and this will avoid the engine being too wet with fuel to start easily when you screw the glow plug back in.

Other methods include removing the engine back plate, and letting the fuel out, or trying to direct the fuel out of the exhaust.

your starter should turn over a 50 no problem.

[Extensa]

So basically I have flooded the engine and it has no where to escape so it is stopping the piston moving to its full extension?
Do you think the Optifuel 30% is ok for now as I got it free with the kit I will get some 20% when it runs out or would you suggest getting the 20% now and saving the 30% fuel for when I have run the engine in probably and start to learn more advanced flying?

Thanks, Mike.

[trillian]

Usually you can clear the fuel out fo the engine by leaning the heli over on the pipe side so that the fuels drains into the pipe. I find that very rarely is removing anything required but if so then pulling the plug or backplate as Jimmy mentioned will clear it out. Sometimes oil residue can be sitting in the pipe and will get sucked back into the exhaust port every time you try to start it. I had this happen to me once with an Align pipe and it didn't happen with other pipes but generally just leaning it over as you turn the engine will allow it to drain out.

A .50 engine is .5 of a cubic inch which is roughly about 8cc. 50cc would be much much bigger and the Align starter most definitely would struggle :-) I use the Align starter on everything smaller than the .91s and it should be fine.

---Just saw your other post. If you're runnning the engine in and / or don't yet need the power of the 30% nitro then you can save some money going with 15 or 20%. I use 15% Rapicon and 16% Bekra on all mine and I'm perfectly happy with that (I do 'sport' flying, F3C style hovering and 'big air' aerobatic stuff and my Raptor 50 is very happy on the 15% nitro).

[Extensa]

oh its .50 not 50 lol thought it sounded a bit powerful I did make the mistake of leaving the bung in the exhaust and turned it over twice before I realised which would probably be the reason it flooded. I will try starting it again tomoz if its not raining hopefully I will get to fly it at long last

[trillian]

oh its .50 not 50 lol thought it sounded a bit powerful I did make the mistake of leaving the bung in the exhaust and turned it over twice before I realised which would probably be the reason it flooded. I will try starting it again tomoz if its not raining hopefully I will get to fly it at long last

Have you had it running before? After a while you get used to the routine and flooding should be rare but it's fairly easy to do. If the engine is new and not yet broken in you'll need to take it easy for a while until the ring and liner bed in. There was a thread on here just recently about engine break-in in general, if you search you can probably find it. If you're just getting started with nitro a little help from a clubmember with some experience could also be very useful (I'm just throwing stuff out here as I don't know what your level of experience is).

[Extensa]

I have been flying a 450 sport v2 electric for about 2 months and using the Phoenix 4 sim everyday for about 3 months but never flown a nitro before. I built it myself for when I join the newton abbot heli club in the new year so I don't have to keep charging batteries off my car The build was fine, set up of the electrics was challenging but I have that sorted now, I have started the engine twice and got it idling nice and smooth with a trail of white smoke but have never taken it off the ground yet, I'm always worrying that I have missed something in the setup which will make it crash as I have no experience and don't know anyone that flies heli's or planes for that matter, so much info to take in :/

[Extensa]

I think I will get some 15% Rapicon as its so cheap and save the 30% optifuel for when/if I get to 3D flying