local0

hello every one!
I use a FS alpha 110-P engine in my sport plane, APC 15*8,COOLPOWER 15%,the max is 8000r.p.m BUT the needle valve is ONLY 0.75 turn,is it OK?
I feel the rocker cover is very very hot after fly 10min,and the r.p.m is only 5000 if the needle valve is open 1turn.
I think something maybe wrong,how can i tune it

thanks!

DarZeelon

Local,


If your engine can run properly, with the needle open as it is; it is obviously receiving enough fuel...

There is no other possibility, that it can receive fuel from elsewhere, for a significant length of time...


The fuel controls have no better 'official' settings, than the ones which allow your engine to run well.

Harry Lagman

That sounds a little low. Peak rpm with that prop should be up closer to 9000 rpm than 8000. This may indicate that there's a problem.

We've got a non-pumped 1.10 at our field doing high eights on the APC 15 x 8.

local0

,did your os110 the rocker cover is very hot after landing?

my friend's YS110 is only warm.

BYW,I have tune the rocker :input 0.04,output 0.08

thanks

togatoga

My Feedback: (42)

the rpm you are getting with a 15x8 is in the lower range of the engine.But expect rpm to be in the lower 8k+ band for this prop size. If the head is very hot, then there cud be some seizing or maybe your fuel is not providing enuff lubrication. If after inspection, you can't detect anything wrong and the engine behaves itself, then try a 14x8 JXF or APC. You can expect to get about 9200rpm with this setup.My 110 gave me 9200 on 10%nitro and JXF prop.This engine likes to be close to the 9k band.
Engines with a pump setup normally requires less needle valve turns than a non pumped engine.Hope this helps

local0

Thank you .

Could anyone told me what your needle valve turnsis ,my HS is only 3/4 turn. I think perhaps is too lean?

w8ye

My Feedback: (16)

You should be able to tell by how the engine runs if it is lean or rich?

Move the needle around a little while the engine is running and see what happens?

local0

I mean : the RIGHT HS needleposition , for example ,the YS110FZ is 1.25turn , my OS 110is only 0.75turn ,mybe is too lean,because my engine is very hot .

mike109

G'day This is what I would do.

1. Open the needle valve slowly. The engine should slow down and become richer and richer.

2. If it does, then tune it for maximum revs and then turn the needle out to drop the revs by about 300 rpm

3. BUT If when you screw the needle valve out the engine does not get richer you probably have the low speed needle set too lean and it needs to be opened about a 1/4 turn or even more.

If the Low Speed Needle is set too lean, the high speed needle will not be able to make the engine mixture richer and you may be running the engine lean as a result.

Mike in Oz

local0

Hi Mike,In fact I following these steps:

1, open the HS needle 1.5 turns , start the engine ,and put the throttle tofull open , at this time ,the rpm is only about 4000-5000

2, close the HS slowly at full throttle status ,then the rpm is raising ,raising

3, when get the max RPM,about 8000,the HS needle is closed to about 3/4 turn, at this time the trottleis full open ,so I think there isnothing about the LS needle,but 3/4 turn looks like TOO LEAN?

thankyou .

mike109

G'day Then as Dar said, if the engine is running well, it is probably fairly well tuned though I tend to tune my engines a little rich so that as the tank empties, the mixture does not become too lean.

Saito recommend you tune your engine with the tank about 1/4 full so that you will never be running the engine too lean. You might like to try this.

But again, as Dar said, the fact that the needle is only 3/4 of a turn open is not a problem in its self so long as the engine is running well.

When I have turned engines too lean, they usually immediately show signs of getting too hot and they usually stop. I think you are close to the right setting but you might like to try the suggestion of tuning the engine with the tank nearly empty.

Mike in Oz

local0

thanks a lot every one.
today I check the engine agian ,and I will try 14*8 prop this weekend.

jaka

Hi!
Engines (carbs) are set by ear! not be how many turns the high speed needle is turned out!

Motorboy

Check there are enough oil out of exhaustpipe, are there enough oil and the engine are running with nice sound, HS needle are well tuned. too little or zero oil not good for engine cause lack of oil. Normal with oil out of breathing nipple mounted at crank case.

blw

My Feedback: (3)

Local0-

The only real need to check a needle position is when it is cranked the first time during the break in process. A lot of manufacturers will give you a needle placement starting point. This is probably due to people like us who hold engines and turn things in the hobby shop.

The goal here is to tune the main needle valve to absolute peak rpm, and then back off about 4-400 rpm on the rich side.

You can't tell much by how hot you think it is running in most cases.

You can tune your engines either by ear or by tach. Both methods are fine.

local0

thnaks.

but I tune the engine by revolution meter

togatoga

My Feedback: (42)

A lot of good advice here from the forummers. Another thing you need to know too is that a pumped engine like yours will run happily at lean settings until it is too late.So I would use a tach to tune that engine. Like what the others have said,once you have peaked it, richen by 300rpm.

local0

Yes， I trust the tach more than my ears.
in fact this is my first OS 4 stroke engine with pump, and I found the tuning is a little diffrentfrom 2-stroke engine or YS110.