Palmerama Posted July 20, 2009 Share Posted July 20, 2009 It starts and throttles to the max fine,>> I disconnect the power to the glow and it is running fine at max,>> I adjust the main needle mixture screw to the correct setting where the rev just peeks to its highest revs.>> It runs fine like this, if I bring the engine down to a fast idle I hear it surge up and down slightly, if I bring it down to idle it will run for some time approx 30 sec to a minute and then give a rev before cutting out. >> Any Ideas of what I could try to stop this surging and cutting out ?>> >> I thought it could be the idle mixture screw that needs adjusting, I have tried adjusting this idle mixture screw but I tend to end up with an engine that will not start, any advice on adjusting this correctly would be great to know if I am getting this right.>> Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted July 20, 2009 Share Posted July 20, 2009 hello palmerama-sound's like it is too rich at the idle end(can't cope with all the fuel)the thing is to adjust the idle needle slowly and give the engine time to react--1/4 turn max--and make a mental note where you start off at...whe the idle is satisfactory-you then will need to adjust the top end needle-you can't do one needle without it affecting the other.. ken anderson........... Quote Link to comment Share on other sites More sharing options...
simon burch Posted July 20, 2009 Share Posted July 20, 2009 I've got one of these, do you find the revs drop of once you take the glow off ??, another good sign it's a bit rich at the low end. Just follow advice above and you shouldn't go far wrong. All the ASP four strokes I've had were all a tad rich on the factory bottom end setting. Whether this is done to be a bit on the safe side, I don't know. Cheers, Simon Quote Link to comment Share on other sites More sharing options...
Palmerama Posted July 20, 2009 Author Share Posted July 20, 2009 I'm managing to adjust the idle screw and then the main needle and get the engine running each time. Still cutting out but some patience needed here as I guess its way out from previous adjustments. Thanks Palmerama Quote Link to comment Share on other sites More sharing options...
Palmerama Posted July 21, 2009 Author Share Posted July 21, 2009 Still no progress, feels like another afternoon wasted on this engine.I have worked through quarter turns on the idle screw from weak to rich mixture and rich to weak mixture and still the idle cuts out. I'll watch the fuel feed tomorrow and see if there is any air going to the carb when on idle, I must be missing something! Quote Link to comment Share on other sites More sharing options...
Ioan Wittmann Posted July 21, 2009 Share Posted July 21, 2009 Posted by simon burch on 20/07/2009 20:20:04: I've got one of these, do you find the revs drop of once you take the glow off ??, another good sign it's a bit rich at the low end. Just follow advice above and you shouldn't go far wrong. All the ASP four strokes I've had were all a tad rich on the factory bottom end setting. Whether this is done to be a bit on the safe side, I don't know. I own several ASP motors, 2 & 4 stroke. The four strokes need to be a little rich as they have a reputation for running hot. Oddly, they need a "hot" plug to run successfully. I always use the Model Technics F7 (actually in ALL my engines, regardless) Try one of those and not too lean on both needles. Ioan. Quote Link to comment Share on other sites More sharing options...
simon burch Posted July 21, 2009 Share Posted July 21, 2009 I've only ever used OS 4 stroke plugs in mine (four stroke that is). Usually getting them to stop is more of a problem !! I never asked what plug he was using. Might be worth a check though. Cheers, Simon Quote Link to comment Share on other sites More sharing options...
Palmerama Posted July 22, 2009 Author Share Posted July 22, 2009 I thought this to, I had a Model Technics F5 Glow Plug (Medium) but I replaced this with an OS ‘F’ Type Glow Plug (£8.50 was I ripped off ??), I tried this yesterday without any change, it still runs fine at full throttle and cuts out on idle.Could someone explain any more what the idle screw is doing I assume the same principle screwing it in weakens it and unscrewing makes it richer and then the main needle screw is the same principle as a two stroke. ThanksKevin (Palmerama) Quote Link to comment Share on other sites More sharing options...
simon burch Posted July 22, 2009 Share Posted July 22, 2009 The idle screw works in the same principle, but it is far more sensitive, and you have to make much smaller increments when adjusting. With the new plug in, I'd put everything back (both main and idle) to the factory settings and start there. Things to watch out for, When you start the model and it's a slow tick over, does removing the glow make a difference ??. Set the main jet so it's running slightly rich, then bring it back down to a tick over. If you open the throttle quickly, does it hesitate, or pump smoke out before revving up (a sign it could be a bit rich). Might be worth checking your plumbing. I had some troubles with mine after an abrupt landing, turned out the clunk had kinked and was causing all sorts of strange running problems. The OS plugs are expensive, but seem to last well, and all my motors run sweetly on them, so I guess they are worth the money. Comes down to personal preference, bit like peoples choice of fuel. Cheers, Simon Quote Link to comment Share on other sites More sharing options...
Palmerama Posted July 30, 2009 Author Share Posted July 30, 2009 Well, I've had another good go at this engine and took some footage to show whats going on as the engine still cuts out! Regards Palmerama Quote Link to comment Share on other sites More sharing options...
Palmerama Posted July 30, 2009 Author Share Posted July 30, 2009 I'm thinking of trying an onboard glow system because if I leave the glow power supply on it idles much better. Regards Palmerama Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted July 31, 2009 Share Posted July 31, 2009 Palmerama You havn't got too much oil in the fuel have you ? Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 31, 2009 Share Posted July 31, 2009 Definitely too rich in my opinion......I found the idle needle on my last ASP was far too rich from the factory.....keep turning the needle in a 1/4 turn at a time until you get there...it may need to go a fair way.....if you get the symptoms of too lean which is usually when the motor just cuts dead when you close the throttle then you know you've gone too far....start opening the idle needle a touch & you will be just about spot on....it can take some time to get there but once set they can be left alone....... Myron makes a good point also...what fuel are you using...a drop of nitro helps the idle no end..... If you persevere I'm sure you will get there...my ASPs run, idle & throttle beautifully....they are good motors!!! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted July 31, 2009 Share Posted July 31, 2009 Steve & Banana rama --Yep I think it's a fuel or too rich prob at idle looking at the eflux (hope I got the right spellig thon !or is there another f in it ?) Whilst we're on the subject & as you are obviously an expert Steve Cough-Cough !--- I am just thinking of building a twin engined Mosquito eventually fitted with two 52 fs' s. I have two but one is an SC & the other is an ASP . They are both from the same era ie Mk 2 - I think .'The spec/size/looks etc seem the same -but can you foresee any probs -Synchronisation etc? I also have an OS 52 fs Surpass but can't resource another one the same spec. -Don't think they make'em any more -Only the 56 - Same thing but different ? G-umpy Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 31, 2009 Share Posted July 31, 2009 Not sure I'm an expert Myron.....I've never built a twin although I would like to one day!! They say an "ex" is a has been & a "spert" is a drip under pressure so under those criteria maybe I do qualify!!!! Certainly ASP & SC are pretty much the same engine so I think you would be pretty safe doing that. One thing you could try is to measure the revs of each engine on the same prop & same fuel....if they both record similar readings then they must be producing the "same" power & this should prevent any problems with asymmetry... If one engine is markedly higher reving then maybe think again.......I just know you're going to ask what "markedly higher reving" is so I would take a guess (& it is just a guess) that if you have a difference of over 1000 revs then that would be too much..... Alternatively look for another OS52 on ebay....!!! Or go electric.............(snigger!!) Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted July 31, 2009 Share Posted July 31, 2009 Steve I will disregard that last remark !I have ( as I said ) been looking for another OS 52 . If anyone has one out there they can have a lot of lekky stuff in exchange . Wrong thread ---Should be on "wanted" or " Swap shop" maybe Thanks for the sensible advice . Can't measure RPM actually -Does that mean I have to spend money on another "Must Have " ? Now you know why I'm so grumpy Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted July 31, 2009 Share Posted July 31, 2009 Steve I will disregard that last remark !I have ( as I said ) been looking for another OS 52 . If anyone has one out there they can have a lot of lekky stuff in exchange . Wrong thread ---Should be on "wanted" or " Swap shop" maybe Thanks for the sensible advice . Can't measure RPM actually -Does that mean I have to spend money on another "Must Have " ? Now you know why I'm so grumpy Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 31, 2009 Share Posted July 31, 2009 Beg borrow or steal a tachometer!!! Someone in your club must have one!!!! & yes I know of your...ah...."experiences"....with electric....thats why I mentioned it!!! Tongue firmly in cheek!!! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted July 31, 2009 Share Posted July 31, 2009 Sorry about the repeat but the cat ('Er indoors's just jumped on my Pup and broke a longeron at the rear of the fuselage .& couldn't remember if I'd pressed "add posting " The only damage so far ---Grrrrrr ! Quote Link to comment Share on other sites More sharing options...
Palmerama Posted July 31, 2009 Author Share Posted July 31, 2009 The 3 vidoes are at different stages of mixture settings on the idle screw, the 1st video was the richest as seen with the smoke out of the exhaust. The 2nd video was weaker with much improved output from the exhaust little smoke maybe a little to weak, the third video was inbetween the rich and weak setting on the idle screw. I took the idle mixture screw through the full range from factory setting to extremely week so week the engine woudn't start, so I've been through the full range. The fuel I'm using is 'Cool Power 20% nitro' it was 5% but i bought the extra nitro to make it up to the 20%. It was always a great fuel for my 2 strokes is it not suitable for this 4 stroke ? The best setting I've found is 5 1/4 turns in on the idle screw, 1 3/4 turns out on the main needle screw and adjusted both aound here ish! Quote Link to comment Share on other sites More sharing options...
Myron Beaumont Posted July 31, 2009 Share Posted July 31, 2009 Palmerama ( what a nomme de plume !) Your main needle setting sounds about fight but as fof the idle -Well I've never screwed it in or out but I can tomorrow if you like to see what it isa ! Too dark to type -Sorry Quote Link to comment Share on other sites More sharing options...
Former Member Posted July 31, 2009 Share Posted July 31, 2009 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Paul Williams Posted July 31, 2009 Share Posted July 31, 2009 I have to say the onboard glow system I bought of Timbo has made my ASP sweet as a nut on tickover I was looking at your video and though its hard to assess the RPM seems very high for a 4s tickover, This leads me to think you may have a problem with fuel getting to the carb without the exhaust pressure being quite high. Has this set up ever run correctly? Is the tank mounted at the right height. This being ok try removing fuel line from carb and blowing very gentle into exhaust pressure line you should get ample fuel with a gentle blow. If your not using proper four stroke fuel get some I would never run a 4s on 2s fuel. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted July 31, 2009 Share Posted July 31, 2009 Glad you like it Paul. Before anyone asks... I am not making these units anymore - sorry Quote Link to comment Share on other sites More sharing options...
simon burch Posted July 31, 2009 Share Posted July 31, 2009 Looking at the vids, there is a pipe hanging down, if this is the third feed from the tank, is it blocked off ??. 20% is way too much for a 4 stroke. I think they run better on 5 to 10%. Is the motor running inverted ??, do you have a length of pipe connected to the breather on the crank ??. It's really hard to comment on mixture settings just by judging the smoke, I run mine on Weston Fuel which hardly smokes at all compared to some of the fuels I've used before. This fuel has been great for both my 2 and 4 strokes. Does your fuel contain synthetic or castor ??. Cheers, Simon Quote Link to comment Share on other sites More sharing options...
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