.. Posted August 1, 2012 Share Posted August 1, 2012 If I close it down more it stops. The tickover did slow when I took the glow starter off. Maybe it's worth leaning of the low end needle now? Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted August 1, 2012 Share Posted August 1, 2012 H'mm...sounds a bit rich then.....the factory settings usually are....turn the needle in a touch...1/4 of a turn or so & see what that does... Make sure the main need is set right first though....4 strokes have a less clearly defined "peak" that a 2 stroke so they are a little trickier to set......get the engine nice & warm first (2 mins at about 1/3 throttle should do it) then open the throttle fully.....slowly screw in the main needle & you should hear the revs increase......you will soon get to a point where you can turn the needle in & the revs stop increasing.....this is the danger zone as you are now effectively making the mixture too lean & the temperature of the engine is starting to rise..... The trick is to get the revs to their peak & then when you notice that you are still winding in the needle for no increase in revs open the needle slightly. The aim is to get the mixture as rich as you can whilst still maintaining max revs......it's easier to do than to describe...... If you are having trouble then the best tip is to approach the guy who DOESN'T contantly fiddle with his engines....once set they really don't need touching unless you change the plug or the fuel....the guy with rust on his NVA is the guy to ask..... What prop are you using? My ASP70 seems verey happy on an APC 13x6.... Quote Link to comment Share on other sites More sharing options...
.. Posted August 1, 2012 Share Posted August 1, 2012 Thanks for that Steve. I think I have an 11-6 on it so will step it up to what you are running . The sound / pitch of the engine is so much harder to hear than with my 2 stoke engines . I will get a bigger prop and have a go at it using your advice, it does make sence it being rich on both needles with the bigger gap at the carb Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted August 1, 2012 Share Posted August 1, 2012 An 11x6......wow!!! thats a 52 size prop......best check for bent valves then.........that must be running pretty quick at full chat.... As I said the peak is much less well defined than a 2 stroke...in sound particularly.....get an experienced club mate to show you & then you will know for ever..... PS...just joking about the bent valves....I'm sure it will be fine...... Quote Link to comment Share on other sites More sharing options...
.. Posted August 1, 2012 Share Posted August 1, 2012 Just looked and it is a 12-6 . Thanks again Steve for your help. Its all good learning and an enjoyable aspect of the hobbie ,funnly enough a club mate who solely flys electric commented recently on how my engines seem to start and run without hassle and as you say once they are set then little tinkering is needed . These 4strokes are new to me so the learning curve starts again. Sat looks a bad flying day so I will head up to the patch and have a good rev session as I doubt anyone else will be there. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted August 1, 2012 Share Posted August 1, 2012 OK 12x6 not too bad but still a touch small.....I have a 12x6 on my 61 4 stroke.....remember that 4 stokes make their power at lower revs than a two stroke so can use bigger props..... Like modern cars, modern model engines usually start & run very well.....you often find that the same people have the same trouble with every engine they own......the common denominator is often....the modeller himself...... Quote Link to comment Share on other sites More sharing options...
William Morrison Posted August 1, 2012 Share Posted August 1, 2012 Weasel, open the throttle barrel all the way as if it is runing at top speed and check the compression. If the throttle is closed when checking you will get very low compression. I would expect a new engine with a 12 X 6 prop would idle around 3,000 RPM. You do have to adjust the idle setting, it is located inside the throttle arm. As you unscrew the idle you are making it richer. Turning it in, makes it leaner. Always adjust the idle in 1/8 th turns, very small adjustments. You have to set the top RPM, then the low RPM setting. So if you make an adjustment or two, you need to go back and readjust the high speed needle. The low speed needle controls the idle and mid range operation of the engine. Once you get it to run at a low RPM, then you need to do snap acceleration checks. If the engine stumbles and then slowly accelerates, it is rich. If the engine stumbles and quits it is lean. But first you really do have to get it adfjusted to run at low RPM.. As the engine gets run in, it will develop more power. And it will idle at a lower RPM, say 2,400 plus or minus 200 RPM. Good luck. Quote Link to comment Share on other sites More sharing options...
.. Posted August 3, 2012 Share Posted August 3, 2012 Success! I re set thre barrel to a more normal opening at idle and tuned the main needle to max , I could hear it this time? It's a more sutle tone but I could defiantly tell at peak revs. I know now that it was way too rich before. Tweeking the low end I have had to go in just over half a turn , it runs nicely now and picks up well , just need this wind to calm down to give it a flight . Thanks again Steve and chaps . Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted August 3, 2012 Share Posted August 3, 2012 Great stuff.....well done Justin..... Quote Link to comment Share on other sites More sharing options...
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