New SC46 - Running issue

[Tony H]

Hi Guys,

I don't usually have any issues with my engines however my new SC46 has given me a slight issue. I have run it in at all different rpms on the ground on two fairly large tanks and I have had 3 flights ( one deadstick near miss landing), but I still can't quite trust it from idle. It often deadsticks from idle if you have to throw the stick up to gain revs (like on an aborted landing). Could be a sign of a new engine not quite run in yet or could it be a mixture issue?

Any thoughts?

[cymaz]

Could be not quite run in yet but try opening the low speed needle 1/4 turn

[Tony H]

The low speed needle crossed my mind too, but I prefer not to touch it unless I am absolutely out of ideas, plus with it being so cold at the moment the low speed needle maybe different because of the cold ( I tend to tweak it only if necessary at warmish temps 15-20c)

[Max50]

What about the plug ?. I remember i use to have problems with my first heli; always use to cut out when revved up from tick-over. They said to change to an Enya No.3 hot plug. I've used them ever since, and have no problems with cuts. Had a new SC 46 . and didn't have to touch the low needle while running in, or after.

Just a thought.

[Tony H]

Thanks Max50,I usually don't need to touch the low speed mixture as you say. Maybe I shoud try a hotter plug since it was probably about 5c out. I was using a new Taylor Std plug.

[Keith Berriman]

Hi Tony if you can obtain a Taylor Glow plug with idle bar you will suprised how much a smooth pick up should be

[Mark a]

I've recently run in a sc46 and sc52 and had to richen the low end needle on both to get them to idle and pick up from low revs. Only turn the needle a 1/32 of a turn at a time though. Both now running very well, the 46 in my Wot 4 and the 52 in my Acro Wot.

Mark.

[Bill Brown 3]

I`m no expert but had similar problems with a new Enya engine, while running in on the bench in my unheated garage during the cold weather it was reluctant to run without a few amps left on the igniter and as soon as you raised the revs it would cut dead, i changed the glow plug and it was a completely different engine.

I do feel that new engines should be bench run initialy though as they are prone to being erratic until they are bedded in even with computerised engineering which does cut out a lot of extreme variation.

Synthetic oil fuels are also good, they cut out a lot of critical carb adjustment.

[Peter Miller]

The cutting out as you open the throttle fast is a sign of a weak slow running mixture on every engine. AS theys ay, 1/8 to 1/4 turn open.

I use Taylor long reach standard plugs and never have any trouble with them. Much cheaper than other plugs and just as good.

Personally I run on 10% fuel, Formula Irvine is good. Lowerr nitro is OK but as I like to have only one type of fuel for all my engines from the smallest upwards I stick with 10% nitro.

[Kit Morpeth]

All previous comments make sense but you didnt say what the engine was fitted to. I have seen problems with insufficient cooling air to the engine and more importantly out of any cowl that may be shrouding it. I had a problem with a 4 stroke cutting due to overheating in the plane. A bit more hacking at the underside of the rear of the cowl to improve airflow solved the problem.

Kit

[Steve Hargreaves - Moderator]

How does it stop Tony.......does it just quit dead when you open up or does it cough & splutter a bit.....if the former its a bit lean...open the idle needle....if the latter its a bit rich...close the needle.....

It might still be a bit new too.....it needs about 1 hours running to free up fully.....

[Tony H]

Thanks guys,

Steve - It tends to stop dead (probably to lean on idle needle)

Kit Morpeth - It's not cowled in it's open to the air

I have riched the mixture on the idle mix by a quarter of a turn to see if that helps, I'll let you know next time I am able to fly it.

[Ronos]

Come across this thread,as I too are having top end running problems with mine. It has had a few tanks through it, both on the bed and in the air, about a gallon in all, it was running ok at first then it started to dead stick at 3/4 to full throttle. It ticks over great,runs great up till 1/2 throttle, no stutter to full throttle ,runs ok when you point the aircraft skywards, runs ok for the first tank, then it's down hill from there. Fill the tank up again, start the engine, ok, idle ok, up to 1/2 ok ,take it to full slowly dies, take it back to 1/2 it picks up again, but it doesn't do it all the time, I mean you can take it to full throttle and it's ok, take it back to idle then full and it's back again. Any ideas

[Denis Watkins]

I would say plumbing Ronos

Just as it loads up high end, and needs pressure, it has none and quits

It can have new pipes and new tank, but still not hold pressure at high end

Check centre bung for tightness, and all pipes tight, difficult to pull off

If pipes come off easily, then so can pressure at high end

[gangster]

Try a different make of fuel. A mate of mine has a brand new OS55. More trouble than any engine he or I have ever had Tried different bottles of fuel that he and I had (all 10% same make). All of the fuel used ran my very old and very reliable sc46 no problem at all. No dead sticks etc. After doing battle for weeks he borrowed a tankful of something else and problem solved. Engine now behaving every flight like an OS should. So scoring a tankful of something else you never know

[Old Geezer]

I guess I might be accused of cheating, but I use an on board glow driver which is switched on for starting and can either be left switched on during the entire flight or set to switch back on at about 1/3 throttle. No more dead sticks when opening the throttle to go round again - weighs only few grams and cheap at only about 12 quid from HK - then hooked up to a diddy little 2S 800lipo I had kicking about - reliably deals with the previous dry mouth: "will she/won't she" situation, particularly on finals.

[Ronos]

Thanks for reply. Denis all pipe work and bung air tight, check all that when I took in out of the aircraft and run it on test bed and it run great, put it back in aircraft run it in garden great, took to site first flight great, second flight trouble.

Gangster, thought ab out different fuel, but because I have mainly 4 stroke and run these on Lazer 5, but it should run ok on this, but is a option. 

Old geezer. Am running a No8 plug, like what has been said in another post might try a enya No3

Edited By Ronos on 25/05/2019 13:23:51

[Don Fry]

Try opening the main needle a tweak, or if you are setting the needle before the flight, set a bit richer. But the OS clones take more than an hour of running to fully bed in.