IRVINE 40 TUNE UP ?

[Tony Jinxy Froude]

Hi, i biught a Seagull Arising star trainer approx 3 years ago & its been sat in my shed for the last 2 years until recently when i decided to resurect her, ive always had a problem fine tuning the brand new Irvine 40 engine that i bought 3 years ago & managed to fire her up today to try & tune it, but find she wont idle at all unless she is permanantly connected to the glow start ! is this because the fuel is at least 2 years old even though its still sealed in the bottle it came in ? or some other problem, can anyone tell me the correct way to fine tune this engine please before i lose interest for another 2 years, many thanks, Tony

[Jonathan Lewzey]

I would suggest that the slow speed running screw is set incorrectly. The fuel is probably not at fault.

If you're not a member of a club, join one and your clubmates should be able to sort it out for you. (difficult to sort out engine problems on just a description)

If you are a member of a club and they don't know what to do - look for another club!

[Tony Jinxy Froude]

Thanks Jonathan, is the slow speed running screw the one on the side with a bent lever thingy ?? if so ive tried this & it still seems to make no difference, will have a fiddle again at the weekend & see what happens, cheers, Tony

[winchweight]

Have you run it in at all? If not, keep it a bit lean until its run in and then tune it up.

[Aslan]

Do you mean rich Shaun?

[Phil Meredith]

i hope he means rich aslan,

[Tony Jinxy Froude]

Yep the engine has been running & ive been tuning it quite well i thought, but when its on tickover and sounds & feels quite smoothe i go to take the glow start off it instantly cuts out.... GGrrr!!! also can anyone recomend a fuel transfer pump to go inside my flight box, i had one but its given up the ghost, are 12v pumps from car washer bottles any good & if so which ones ? , cheers Guys,... Tony

[Helidel]

If the engine stops when you remove the glow start then the plug is u/s and needs replacing.
Hand (on the outside)or electric pumps from your LMS will suit, whatever you prefer.

[winchweight]

Sorry, I meant rich...... oops.

[Aslan]

I would do as Derek says first,if it still cuts, the low speed needle would be the next thing to have a look at.

[Helidel]

This is Derek Tudor
Reversing back to my old nickname "Helidel"

[Tony Jinxy Froude]

cheers Guys, it this the screw next to the servo linkage on the throttle or the brass coloured one with a small handle on the side. Ine now found an Irvine fuel transfer pump to go in my flight box & it works a treat so at least thtas something that works !!, by the way in using 2 sorts of fuwel recommended to me when i started, ive got half a bottle of the Model Technics contest 10 & half a bottle of Model Technics expert mix GX-5 are these any good for what i need Oh and i bought a No3 glow plug yesterday as recommended by the model shop, cheers, Tony

[Jonathan Lewzey]

the slow running screw is on the caburettor inside the throttle arm on the engine. I'm not sure where it should be set, not being great at engines, but my O.S 46AX suffered at the Idle and the screw cured it. If you have the instruction manual, it should tell you where the factory-set position is.
Jonathan

[Helidel]

The slow running adjustment (secondary needle) is inside the carb in the opposite end to the main needle. the setting is only used up to about 1/4 -1/2 throttle opening (not the stick position)from tick-over if you can open the throttle reasonable quickly without faltering then the secondary needle is OK. but bear in mind it will also have some effect on the slow running(tick-over)It then becomes a matter of
"tweaking" Only turn the secondary adjustment 1/4 of a turn each time .. in for a weaker mix and out for a richer mix.
With most engines you only "peak" the output with the throttle wide open and using the main needle only never try to adjust the secondary needle during this stage! Watch out for the rotating prop or you'll Ouch!!

[andrew brasier]

hi had the same problem with my apc 40 which caused the demise of my trainer cut in mid flight and the instructor crashed into the trees i knew nothing about tuning engines found an article on the web, you need to get your mixture screw set up this is the opposite side to the throttle arm this should be set at full throttle , wind it out just till the engine starts to burbel then gradually screw it back in till the revs pick up nip the fuel supply pipe to the carb if it revs up mixture is to rich (wind mixture screw in) if the engine dies mixture is to weak(screw out) if revs pick up for a few seconds then engine dies the mixture screw is set right, to set the idle screw open the throttle from idle if it splutters its way up to fullrevs then idle screw is to rich,(screw in) if engine cuts when reved up idle screw is to weak(screw out) when you have it set up right put engine to full revs pick up the plane and hold it up at an angle this is the lean out check if the engine cuts you need to give the mixture a couple of clicks out, one of my club mates also told me when you get the engine set right give two or three more clicks out on the mixture screw as the engine will lean out when the plane gets in the air hope this is help ,also watch your fingers as i learnt by bitter experience

[the unmagnificent man]

Hi Tony, heres my version of what everyone else has just told you.

Firstly look in your instruction book and make sure that the fuel tank is at the correct height in accordance to the carb. Normally the centre line height of the tank is just above the top of the carb. Then check that when you open the throttle that the barrel rotates to its maximum opening, and that when you close the throttle that the barrel closes but leaves around a 1-1.5mm gap.

Next familiarise yourself as to what is the main needle and what is the low end needle. The main needle is the larger of the two. the low end is usually brass.

If the engine is totally wrongly adjusted try starting like this..... Unscrew (anticlockwise) the main needle about 5 turns.  Screw the low end needle in until it stops, then screw it back out 2 turns. Next screw in the main needle intil it stops. Now place a piece of fuel tube onto the fuel nipple on the carb and blow. Start to unscrew the main needle until you hear a hiss. This is a basic set up and should allow the engine to start and we are then ready for fine tuning. Put the fuel pipe back on.

Still here? good. Assuming you now get it started. With the engine running and the glow still attached open the throttle fully and listen. Carefully turn the main needle clockwise slowly. You should hear the engine start to sound a little more powerfull. With this point reached and the engine still at full, raise the nose up. If the motor starts to die you need to put the plane level again and open the main needle (anticlockwise) about 2 clicks. Keep repeating this until you can lift up the nose without the engine dying.

If you have got this far you now just need to fine tune the low end.

Close the throttle and let it tick over for about 10 seconds. If it wont tick over you need to open the low end screw a tiny bit (imagine 2-3 minutes on a clock) If it does tick over you then need to try this..... open the throttle reasonably quickly and listen. If it kept running but didnt speed up very quickly then its too rich (too much fuel) you need to turn the low end screw in (clockwise) about the equivalent of about 1 minute and try again....until the sound of the engine speeds up as quickly as you open the throttle.

If however when you come to tune the low end you open the throttle quite quickly and the motor just dies then its probably too lean (not enough fuel)...In this case open the low end needle about the equivalent of 5-10 minutes and try again...This should put you in the position above. I.E engine too rich....Remember too rich is better than too lean.

After all that you now need to go through it all again with the glow start removed starting at the point of engine at max and lifting the nose up.

I know its a long winded version but its best tell all and not assume you know everything......Good luck and let us all know how you get on.   Al

[Tony Jinxy Froude]

Thanks guys soo much for your advice, ive put the planes away now until the warmer months, but have printed this whole thread off & put it in my flight box ready for when i resurect them again later, thanks again & have a great christmas, all the best, Tony

[Jack Tanner]

try a hotter plug