Can YOU tune a 4 stroke by ear?
#26
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RE: Can YOU tune a 4 stroke by ear?
I am still concerned about how much smoke I have coming out of the exhaust. I lean it out til its really ripping then richen it quarter turn +/- and its so smokey. How smokey would you say is too smokey?
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RE: Can YOU tune a 4 stroke by ear?
That depends on the make of the engine. Saito's are very sloppy and Magnums are much cleaner and I can't help with OS since I only had one.
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RE: Can YOU tune a 4 stroke by ear?
Alright mines a Saito, my first, so perhaps what I feel is too rich based on smoke is just normal, even at a lean setting its still puttin out quite a bit of smoke.
#29
RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: bob8619
Alright mines a Saito, my first, so perhaps what I feel is too rich based on smoke is just normal, even at a lean setting its still puttin out quite a bit of smoke.
Alright mines a Saito, my first, so perhaps what I feel is too rich based on smoke is just normal, even at a lean setting its still puttin out quite a bit of smoke.
#30
RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: AmishWarlord
OK Now I have a question.
Does the pinch test work on four strokes like it does in two strokes?
OK Now I have a question.
Does the pinch test work on four strokes like it does in two strokes?
Kelly, Great post. Other than the low end adjustments, Im pretty much there, but wont fine tune the low end until after the 5th flight, engine is just broke in. Going to follow your tips to fine tune it, and my OS, which is too lean. Right now the Magnum I got it down to 2200 RPM at idle, and it will go lower, but dont want it too low, hate to have it dead stick on final. Definate rich on the low, but it revs up, no burble, no hesitation, but slow to rev, lots of smoke. It should be a sweet motor once fully broke in.
#31
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RE: Can YOU tune a 4 stroke by ear?
you guys that suggest tune to max then drop XXX(X) rpm rich isnt good info. each engine is different, each airframe is different, different fuels and different tank instalations will cause different readings in the air. i only use a tach for testing props thats it. i never tune an engine by the tach then go fly. you most always will be lean inflight. fot the new guys at engine could use a tach to set max but the backing off part is hard to set a set value in a forum. get help at the field.
Pinch test on most four storkes dont work either because of the time it takes for the fuel to go thru the carb and to the engine. setting saitos you should turn the neele a couple of clicks either way then wait 3-5 seconds. it takes some time for it to catch up.
Pinch test on most four storkes dont work either because of the time it takes for the fuel to go thru the carb and to the engine. setting saitos you should turn the neele a couple of clicks either way then wait 3-5 seconds. it takes some time for it to catch up.
#32
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RE: Can YOU tune a 4 stroke by ear?
Sure you can use a tach to set the engine rich enough to run right in the air. It's just a matter of technique. Here's my OCD way of doing it on an engine that's broken in well enough for fine tuning to be meaningful: First, I find what the max rpm is. That's where I want the engine to be in the worst case scenario, which would be on a straight up line with maybe 1/3 a tank of fuel. I then use the tach to go back 300 rpm rich, then test that upline tune. It's too dangerous to try and tach the plane while holding it vertical, so I listen for it to give me the slightest rpm increase (300 is about the smallest change my ears can detect) and then hold it in that position for 10 seconds. I never do up lines that long, but I know that if the engine does not lean out and change its sound or quit then I'm set rich enough. If that test fails, I go to 500 rpm rich and try again. When I'm happy with that, I fill the tank up and check how many rpms I'm off of peak on the test stand, and that becomes my perfect tune for that engine in that plane with that tank setup. For the low end I can be very accurate and actually a good bit faster about setting the idle and transition mix. I get the lowest idle that the engine will run reliably and tach it over about 30 seconds. I keep leaning the needle until it holds steady (always fluctuates a bit, but I'm looking for it to stay in the same range) then I drop it down a little lower. Not surprisingly, the lower I set the idle the more sensitive the engine is to having the LSN set right. Once I'm down to the idle setting where I'm only once click between loading and slowly dying and suddenly leaning out and dying, I go back up maybe 300 rpm and check the transition. 90% of the time it's dead on. With 4 strokes it's a little different on the low end as I simply tweak the needle for the highest reliable rpm at the idle setting then work down the same way. The high end is then double checked to make sure it's still at that baseline I established earlier, and I'm done.
Some will ask "Why go to the trouble?" My response would be that it doesn't actually take long to do assuming I start with an engine that's close to being right to begin with. It certainly takes less time than chasing a proper idle and waiting to see if the engine is going to load up instead of instantly seeing what it does. And it definitely takes less time and money than rebuilding an engine that was damaged in a lean run. Of course some will say to just run it "a little rich" and be done with it. I found in my testing that my version of what sounded "a little rich" was about 1000 rpm off peak. That's about one engine size, so my .46 was actually flying like a bushing .40. So I take the time to get my engines tuned perfectly so that I get the power out of them that I've paid for without going too far and damaging them.
Some will ask "Why go to the trouble?" My response would be that it doesn't actually take long to do assuming I start with an engine that's close to being right to begin with. It certainly takes less time than chasing a proper idle and waiting to see if the engine is going to load up instead of instantly seeing what it does. And it definitely takes less time and money than rebuilding an engine that was damaged in a lean run. Of course some will say to just run it "a little rich" and be done with it. I found in my testing that my version of what sounded "a little rich" was about 1000 rpm off peak. That's about one engine size, so my .46 was actually flying like a bushing .40. So I take the time to get my engines tuned perfectly so that I get the power out of them that I've paid for without going too far and damaging them.
#35
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RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: koastrc
One of our members test his tach by pointing at a light bulb, light on. He says the tach reads the RPM of the generator at the power house and the power house RPM is constant. Perhaps that is true. What is true, this guy always seems to be correct in other areas. I have never owned one, but have used his.
One of our members test his tach by pointing at a light bulb, light on. He says the tach reads the RPM of the generator at the power house and the power house RPM is constant. Perhaps that is true. What is true, this guy always seems to be correct in other areas. I have never owned one, but have used his.
The TNC will work from several feet back from the prop, it's one of the selling features and it is affected by light but so far it still reads the rpm no mater what or where. It's just more then most people require at $100.00 a pop.
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RE: Can YOU tune a 4 stroke by ear?
If your comfortable tuning by ear then by all means. If your not sure then get a tach that works. No need to spend big money. I use the Hobbico tach and they all work well at my field. On the other hand we have a few glo-bees and they all jump around.
One thing not mentioned is tune your saito with only 1/4 tank of fuel. I like to tune with the amount of fuel in my tank that I am landing with. That way you can get that extra 100 rpm's that some of us want. I richen my 2c by 200 rpm's and my saitos by 100 rpm's. By tuning with 1/4 tank you know that it will only get richer by adding fuel instead of guessing on how much you THINK it will lean when flying and compensating for it. I don't like guessing.
http://www3.towerhobbies.com/cgi-bin...&I=LXPT32&P=ML
One thing not mentioned is tune your saito with only 1/4 tank of fuel. I like to tune with the amount of fuel in my tank that I am landing with. That way you can get that extra 100 rpm's that some of us want. I richen my 2c by 200 rpm's and my saitos by 100 rpm's. By tuning with 1/4 tank you know that it will only get richer by adding fuel instead of guessing on how much you THINK it will lean when flying and compensating for it. I don't like guessing.
http://www3.towerhobbies.com/cgi-bin...&I=LXPT32&P=ML
#38
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RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: bob8619
I am still concerned about how much smoke I have coming out of the exhaust. I lean it out til its really ripping then richen it quarter turn +/- and its so smokey. How smokey would you say is too smokey?
I am still concerned about how much smoke I have coming out of the exhaust. I lean it out til its really ripping then richen it quarter turn +/- and its so smokey. How smokey would you say is too smokey?
I still fly with some guys that will tell me my engine is running lean because it has very little smoke trail. I was just testing a new fuel when Power Master was out of production. It only had 16% synthetic oil. The fellows decided I had the engine tuned properly the next flight because it was smoking again, I never touched the needles, I did add two ounces of Klotz oil blend in the fuel can. This was a YS engine and they tend to not have a big smoke trail when tuned correctly, the Klotz blend has 20% Castor oil in it, Castor oil smokes. Just tune the engine and forget the smoke trail, some engines and some fuels just tend to smoke more then others.
#40
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RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: bob8619
Roger that. Smoke doesnt bother me just wanted to be sure it wasnt because it was too rich.
Roger that. Smoke doesnt bother me just wanted to be sure it wasnt because it was too rich.
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RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: Gray Beard
Yep, a junkie told me that.
Yep, a junkie told me that.
On vinyl just for you old timer. I couldn't find it on 8 track.
It's time for me to fly. [&:]
http://www.youtube.com/watch?v=keQcg-r2YI8
#44
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RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: GaryHarris
On vinyl just for you old timer. I couldn't find it on 8 track.
It's time for me to fly. [&:]
http://www.youtube.com/watch?v=keQcg-r2YI8
ORIGINAL: Gray Beard
Yep, a junkie told me that.
Yep, a junkie told me that.
On vinyl just for you old timer. I couldn't find it on 8 track.
It's time for me to fly. [&:]
http://www.youtube.com/watch?v=keQcg-r2YI8
I gave the system away when I moved here, I have no place I could set it up that is big enough.
I have gone to the CES show a number of times and when you go in to listen to the 50K a piece speakers you are listening to Vinyl through an Analog sound system. It was discovered a long time ago Vinyl and Analog has a much better sound quality. In my house today I have surround sound, good but it is just lacking something?
#45
RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: bob8619
Roger that. Smoke doesnt bother me just wanted to be sure it wasnt because it was too rich.
Roger that. Smoke doesnt bother me just wanted to be sure it wasnt because it was too rich.
You may not be able to do anything about that though... My Saito's don't seem very smokey, but I've seen other people with VERY smokey Saitos... I wonder if it is due to a valve problem?
#47
RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: bob8619
My fuel was purchased in 2008, not sure if that plays into the smokeyness
My fuel was purchased in 2008, not sure if that plays into the smokeyness
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RE: Can YOU tune a 4 stroke by ear?
ORIGINAL: Gray Beard
You laugh but before I moved here to Vegas I had one huge sound system in my shop. My shop was our old Mobil home and 1000 sq. ft. it was a quad system with four matching book shelve speakers. Why they called them book shelve I will never know? I needed a dolly to move them around! Truth!! I had a super turn table too with adjustable tracking, really nice!!! I used to go into Merced to a thrift store and spend hours going through there record file, For $1.00 a piece it was a deal.
I gave the system away when I moved here, I have no place I could set it up that is big enough.
I have gone to the CES show a number of times and when you go in to listen to the 50K a piece speakers you are listening to Vinyl through an Analog sound system. It was discovered a long time ago Vinyl and Analog has a much better sound quality. In my house today I have surround sound, good but it is just lacking something?
ORIGINAL: GaryHarris
On vinyl just for you old timer. I couldn't find it on 8 track.
It's time for me to fly. [&:]
http://www.youtube.com/watch?v=keQcg-r2YI8
ORIGINAL: Gray Beard
Yep, a junkie told me that.
Yep, a junkie told me that.
On vinyl just for you old timer. I couldn't find it on 8 track.
It's time for me to fly. [&:]
http://www.youtube.com/watch?v=keQcg-r2YI8
I gave the system away when I moved here, I have no place I could set it up that is big enough.
I have gone to the CES show a number of times and when you go in to listen to the 50K a piece speakers you are listening to Vinyl through an Analog sound system. It was discovered a long time ago Vinyl and Analog has a much better sound quality. In my house today I have surround sound, good but it is just lacking something?
Bob, as opjose said, you should be fine.