Doesn't seem to matter which engine/plane I'm using, after a flight, I fuel up to go straight up again, I can't get a hot engine to fire up for a good few minutes of prop flicking.. I've tried little priming (1 or 2 flicks) lots of priming 'till the fuel is dripping out the venturi, and no priming, not until the engine has cooled down will it kick into life.. is there a secret method that some kind person can share with me please?!
 Ta very much
Phil

I have problem mostly with the OS FP.20 (iron piston), and an old ST C.35. it's nearly impossible to start when hot.  But with the OS.46LA, Stalker .61, and the OS.40VF, they usually starts with a few flips /choking the intake for prime. and one bump off the compression. (Stalker .61 & .40VF are inverted)  

Hi Phil,

We have a double system up here in Canada, metric and Imperial... so I understand the temperature you are mentioning. Certainly not too hot. Kinda like here...
I can't comment too much on the engines you are running except for your OS .35S which should be running more cartor oil to cool it down. It does have an iron piston.
You should be running, from what I have read here, at least 26%-27% mostly castor. I run 29% all castor in my os 35s.

Good luck!

-Dan

Hi guys,

If ya use a starter, no problem, just spin the engine and she'll start. The starter saves finger, props, just can't figure why C/L group is against starters?? Most engines if ya got the proper washers and prop up front the crank will not hit the back plate. Good luck and watch out for them fingers, ya might need them??
Gary

That's a bit strange, Phil. I'm using Max-S 35s and SS25/30s also, with virtually identical fuel and plugs to yours. The OS (mounted inverted) just needs to be refuelled and it will start first flick when hot, without even any choking. The SS30 (mounted sidewinder) likes to be choked a couple of times, turned over a few times more, and will then start first or second flick. I don't know why yours would be any different, unless it's to do with the battery - I use a Gates cell putting out 2V.

The ones we do have a bit of trouble with are things like old OS 15s and Enya 15s. They get pretty hot, especially if they lean out at the end of the tank, feel soft in the piston, and can't seem to be hurried. A couple of extra chokes sometimes seems to help, as does the suggestion of squirting a bit of fuel on the head.

Take a leaf out of the Team Race guy's books, if you simply must start a hot engine again the squirt some raw fuel over the block to cool it down.

Just in case you are wondering, I have never seen one catch on fire doing this - the outside of the block simply is not hot enough.

   Oh, goodness, don't dump fuel on it. We routinely fly back-to-back in practice, and I used to fly flight after flight by myself back in the Fox 35 days. Land, fuel up, go again.

   It's a matter of technique and it tends to differ from engine to engine. Many times it takes very minimal if any choking/prime. All of my PAs, for instance, took very little choking if was still hot enough. Let it cool a little bit more (i.e. fuel up and then have a conversation or a few minutes) and then it requires maybe *one* pull-through with your finger over the intake, and you had darn well better get it the first time. Of course if it cools all the way down, normal light choking.   This is pretty typical of ABC/AAC engines. The RO-Jett takes a few chokes and a few aerations when hot but is otherwise similar.

   AAC/ABC engines are prone to "shrinky piston syndrome" if you over-choke them when hot. If you overdo it, it will kick on the first back-bump but not run because it's too rich, and then dump the excess cold fuel on the bottom of the piston. It shrinks, the liner doesn't, and the whole thing feels like you unscrewed the glow plug. David's solution is to just remove the battery, flip it through 20-30 times to equalize the temps and aerate, and when you feel the compression come back, attach the battery and back-bump.

    I got dead-nuts reliable hot starts with the Fox by fueling, attaching the battery, and pulling the engine through compression with my finger over the intake until I got one bump, the removing my finger and flipping through immediately. 20 times in a row, no problem. First time I tried that with an ST46, it got so much fuel it locked up.

   This is all with inverted engines. Side mounts are harder and upright is the hardest to get started in any circumstances. They are far worse cold than hot (because hot you don't need to choke them much).

     If a Fox starts reliably hot, you can figure out how to start anything hot.

   Brett

 

Thanks to all for the comments, appreciate it. Its good to know that I'm not alone with this but even better that some of you guys have no problems with the same engines as I'm using...that means there is a way, I've just gotta find what 'll work for me. I'll try opening the nva as suggested. I do have an electric starter, hate using it, sort of cheating?, so that only comes out when I've worked myself into an exhausted frenzy..
BTW my glo starter registers 1.37v when fully charged.Getting a good orange glow so don't think thats an issue..
Phil