Irvine 53 issues

[Snorbitz]

Having flown trouble free for a few dozen flights i was suddenly faced with my first "dead stick" right out of the blue. Having landed safely (just) i thought i better have a good look into what was going on. When i got back to the pits the first thing i noticed was that the fuel pipe to the carb was empty despite there being plenty of fuel in the tank....if i re-primed the carb and started it up the engine would run for a few seconds then cut out again so when i got home i checked all the plubing and changed any suspect bits and still no joy so i decided to strip the carb down. I removed the hight speed needle and the low speed and blew it all through with an air line. What looked like a piece of fluff which i now suspect was some old felt filter media shot out of the small brass fuel pipe connector inlet., great i thought thats the problem sorted. Re-built the carb and tried again...Nothing!! After some more research i discovered that in curing one problem i had caused another. When i rebuilt it i had wound the idle needle all the way in...stupid boy!!, so i've now wound it back out and while the engine runs ok above half throttle its a pig to start and frequently cuts out below half throttle especially when warmed up. While there is a general rule of 2-2.5 turns out for the high speed needle i can't find any rules/info for the idle needle because i'm sure thats where my problem now lies.

Cheers

[Grant Darnley]

Can't remember if this works with these carbs but got to be worth a punt.  With the main needle at the manu. rec'd starting point, put a long(clean) piece of fuel tube on the carb nipple and blow into it, then wind the idle needle in till the air noise stops, then slowly back out till it JUST starts again.  This will get you close, then its just a matter of running it and tweaking in ever smaller increments until you get there

[Snorbitz]

Cheers Grant, There's no reason why that shouldn't work so i'll give it a go tonight and see what we get. The other thing i noticed was how easy the idle screw was to turn, should there be any o-rings on it?, i seem to remember a spring but that was it, i would say it could probably turn just with engine vibration which is a bit of a worry.

[flytilbroke]

My .53 has high end setting of 1-1/2 to 1-3/4 turns out, your figure seems too rich. Yes, the secondary (idle) needle has an "O" ring. It does not have a spring. Grants advice is sound.

[Steve Hargreaves - Moderator]

Just to add to Grants advise the throttle should be set to idle (throttle barrel about 1-2mm open) before the huffing & puffing starts !!!!!

Run the motor & set the main needle for max revs then open it a few clicks (always trade a few revs for a bit of smoke...means the engine is getting enough oil!!). Now leave the main needle alone. Close the throttle...if it cuts dead the idle mixture is too weak...open the idle screw slightly & try again. Once the motor will idle let it tick over for about 30 secs & open the throttle. If it cuts dead its still too lean...if it splutters,  coughs & smokes before picking up or cutting out its too rich...screw the needle in slightly....

Also stop the motor before tweaking the idle mixture......not only will you keep all your fingers intact but it is impossible to acurately adjust the idle mixture with the engine running as adjusting the screw will move the throttle barrel slightly. It can take some time but persevere & you will get there

[Snorbitz]

Cheers chaps.......can i just throw this at you and see what you think. I've now wound the idle screw out to the point where i no longer get dead sticks and there is a very slight haze of smoke from the exhaust at idle. When i open the throttle there is almost like a dead spot before it picks up and takes longer than i would expect to get to full grunt.........the problem is less noticable when its hot (straight after landing). Winding the high speed needle out doesn't seem to help much and makes it "splutter" more than it should. I don't know if its just me but it seem quite thirsty too......15 mins flight is down to 10 mins now. It would indicate too rich but i'm not so sure. Your thoughts would be appreciated.

Thanks

[Steve Hargreaves - Moderator]

The smoke depends on what fuel you are using......castor will smoke more than a synthetic oil. If it hesitates before picking up I would suggest it is too rich...especially given the higher fuel consumption......also at idle the main needle has very little effect on the fuel flow...it is controlled by the idle screw. Tune it for max revs first using the main needle & then tweak the idle screw. My guess would be that the idle screw should be just level with the top of the tube into which it screws.......

Allow the motor to warm up fully before you try & set the mixture too. You can't acurately tune a cold motor..... a couple of minutes at a fast idle should do it.

[Snorbitz]

Yeah that makes sense really........i've got the idle screw set just below the top of the tube so maybe it just wants to come out another 1/2-1 turn.  Its Model Technics Irvine Contest 10 fuel with 18% klotz oil........seems to run on it ok but my word its messy......and very orange.!!

I'm flying at lunch time so i'll give it a tweak before i go and see how it responds.

I also found that it prefers the OS A3 plug to the OS No8 i tried in it for a few flights.

[Steve Hargreaves - Moderator]

Again if its running rich there will be more oil going through it hence more mess. Synthetics are usually better than castor in this respect........

Flying at lunchtime....very jealous.....weather here is perfect flying weather.....high cloud, bright, odd patch of blue, no wind....& heres me stuck inside preparing a presentation......the boss wants how many slides....?? (sigh)

[Snorbitz]

I'm lucky to have a strip just 1 minutes drive from work so i fuel/charge up at tea break to save time then pop over at lunch and can usually get about 40 mins in before stopping to clean down and pack away.I'm trying to work on my touch n go's at the moment so the weather this week has been great.....monday was a bit windy/bumpy so i just did circuits and a couple of landings..good practice for me though, and its looking good again today although its a bit murky out there. The weather's looking good for the rest of this week and into next but the wind will be getting up again end of next week.

[Steve Hargreaves - Moderator]

Now you're just trying to upset me!!!!!

[Snorbitz]

Well a 1/4 turn out on the idle screw seems to have done the trick. Seems a lot more perky. I might get the guys at the club to breath on it just to be sure but i think its there or there-abouts now so thanks very much for the pointer.

PS did i mention its absolutely perfect out there.....5mph wind straight down the strip.

[Steve Hargreaves - Moderator]

[Ed Darter]

Are Irvine Carbs not fuel bleed ? (as opposed to air bleed) If so, 1/4 turn out would richen the mixture wouldn't it ?

Either way it probably doesn't matter as it sounds as though you have sorted your issue.... i'm just curious !

Ed

[stuey]

I have been having an issue with starting my Irvine 53 recently, which i had put down to the clunk coming off the inlet tube. I was hoping to have no probs this morning when i went out, but i did. The engine would barely start after turning over for ages, then wouldn't  throttle up at all. After messing around for ages, i tried leaning out the bottom needle thinking it was too rich. I have had very good throttling in the past, which helped confuse me. I could not get the damn thing to start again and gave up.

During my messing i noticed 2 things, there seemed to be no fuel entering the carb despite having no probs getting fuel through the inlet line, and the bottom end needle seemed a bit too easy to turn. Having read this thread and stripping the carb and finding no blockages, i have come to the conclusion that the bottom end needle has been closing itself down and eventually blocked the fuel from coming in. I think i proved this by blowing through a piece of tube on the inlet, with the bottom end needle screwed right in no air can be pushed through the carb. Once opened til the needle is about flush with the housing, the air just starts coming through as described above. I can't remember how many turns the needle was out originally, never needed to adjust it much. I am pretty sure it was a long way into the tube earlier whilst i was trying to run it, which i think was stopping the fuel getting through.

In conclusion, i think the o ring on the bottom end needle is letting the needle screw itself in during running causing fuel starvation

[stuey]

Just tried starting the engine, fired second go... hopefully my ramblings above have proved correct. Think a new o ring may be in order

[flytilbroke]

Yup, I have replaced "O" rings three times on my Irvines. Mostly the one under the carb body though, which perished. As I got them as a set I just changed the needle rings as well.

[Tom Doyle]

Just come across this thread so my contribution is probably too late. I and two clubmates have all had similar problems with Irvine 53s i.e. undersize/loose fitting 'O' rings on idle mixture screw. I was the luckiest in that I noticed the idle screw on my 53 had almost unscrewed itself during pre-flight checks. My two clubmates weren't so lucky, their mixture scews dropped out in flight! All three engines suffered this problem after about half a dozen flights. Interestingly, Ripmax sent out new mixture screws immediately and without quibbling - we got the feeling we wern't the first to experience this particular problem and that Irvine may have had a quality issue.

Tom D 

[conrad taggart]

Posted by Tom Doyle on 25/01/2009 23:02:42:

Just come across this thread so my contribution is probably too late. I and two clubmates have all had similar problems with Irvine 53s i.e. undersize/loose fitting 'O' rings on idle mixture screw. I was the luckiest in that I noticed the idle screw on my 53 had almost unscrewed itself during pre-flight checks. My two clubmates weren't so lucky, their mixture scews dropped out in flight! All three engines suffered this problem after about half a dozen flights. Interestingly, Ripmax sent out new mixture screws immediately and without quibbling - we got the feeling we wern't the first to experience this particular problem and that Irvine may have had a quality issue.

Tom D

Roll on 10 years and I seem to have the same problem as above. First problem occurred in flight. Didn't have a new secondary screw to replace the one that fell out so put in a new carb. When going to tune it up I was struggling (it my first glow engine model) I thought the secondary screw moved too easy. Lo and behold asked a more experienced member within my club and he noticed it right away and commented on it. Which brought me here and to this thread.

Obviously Ripmax aren't going to send out new secondary screws as Irvine is long gone and Ripmax don't appear to have any stock. Does anyone know how the new secondary screw differed to the faulty one or, even better, know a fix to the problem ? Plus has anybody got a parts diagram for an 1850 Jet Stream carb which they could please share ?

Thanks C

[Denis Watkins]

PTFE tape Conrad

Cut a neat piece to wrap the threads once very tight

Then locate the needle carefully had into the carb threads

[Jon H]

If your slow run needle looks like the one in the picture below then the o rings you need are BS004. If you cant find them elsewhere send me (laser) a self addressed envelope with a few 1st class stamps to cover about a quid and i will send you some.

[Nigel R]

there is still some stock of spares for these carbs

**LINK**

[conrad taggart]

Jon that's a very kind offer. Just managed to retrieve my plane from storage the needle look like which is slightly different to the one shown in your pic **LINK** (better picture than the one I just managed to take).

In the meantime, I managed to get my hands on an overhaul kit identical to this **LINK**.

Can anybody please tell me which if any (given that the needle is a different design) of the small o rings I should fit and does it simply fit into the brass bit of the carb where the needle came came out of  (if it does there was no o-ring present when I removed the needle) ?

Thanks 
C 

 

 

 

 

Edited By conrad taggart on 09/11/2019 15:59:50

Edited By conrad taggart on 09/11/2019 16:39:02

[conrad taggart]

Sorry here is the o-ring over-haul kit i was referring to above (second link) **LINK**

[Frank Skilbeck]

The O ring should go in the groove on the slow speed needle just behind the screwdriver slot, the Ripmax photo shows a low speed needle with the O ring fitted.