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Old 09-17-2014, 08:03 PM
  #27601  
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Originally Posted by jeffie8696 View Post
This may have been touched on here in the past but I haven't seen it.
I have a nice Saito .45 , the one with the elbow joint intake on the carb.
Picked it up new with no box for a song and its a great engine like all my other Saitos. However it doesn't give me the amazing idle like the rest, best it can do reliable is about 2500/2600. From what I have been able to gather this isn't particular to my engine as I have read some old reviews and they encountered the same thing.
Just wanted to be sure it isn't me, it pulls my 4Star54 around really well, very reliable and powerful for an engine its size.
Unfortunately I had been using my (purchased new, just broke in) Saito 62 but it keeps dead sticking for unknown reasons(I suspect a main bearing not seated).
Jeffie, I have two of these also. Great little engines other than the idle quality. My problem was an inconsistent idle on both. Most rc carbs have a spring that pushes the rotating barrel out. The 45's do not have this spring so the barrel is free to move side to side in the carb just slightly. This is also moving the low speed needle in and out of it's orifice, again just slightly. With the very small amount of fuel being used at idle, I believe this side movement of the barrel creates a changing fuel ratio.
What to do about it?? I don't know if a spring could be added to mimic what the other carbs have. If not, I've thought of "rigging" an external spring that would pull lightly on the throttle arm. I have not run these in quite some time.
I've only run the 65 and 82 besides the 45's, both have been fantastic! My 82 needed a rich low end for a few gallons. All of it's problems were tuner induced- too lean on the bottom.
Good luck, MikeB
Old 09-17-2014, 08:23 PM
  #27602  
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I sneak up that lean spot on the low speed needle. I ease the throttle up and see how it handles it. Then, I increase throttle quicker. If it sounds right, repeat. All the backfires I've had have been just gerbil farts. I'm waiting for the day to come when I get a good prop slinger.
Old 09-18-2014, 02:08 AM
  #27603  
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Barry always gives good practical tuning advice,and taking your time tuning plays big dividends.Once the hsn is set properly take your time on the lsn,occasionally you may have to go back and forth a bit re main and low speed needles,with patience you work it out.If you go a bit too lean on the lowspeed needle with the bigger saitos especially they will kick a prop off when you get hamfisted with the throttle.Now,if that happens while you are ground running your engine and the prop flies off and hits some armchair expert gerbil well and good.

ps bic biro's or lighters are a good source for throttle barrel springs on the outside

Last edited by Rudolph Hart; 09-18-2014 at 02:21 AM. Reason: more bs
Old 09-18-2014, 03:42 AM
  #27604  
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I can't see a not quite seated rear bearing as being able to cause dead sticks, even if it wore a hole in the back plate it would not effect the fuel mixture or anything else. I suspect LS needle too lean or too rich.

Last edited by Hobbsy; 09-18-2014 at 06:41 AM.
Old 09-18-2014, 06:20 AM
  #27605  
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Too bad you didn't try gas in the engine with the higher CR. Do you still have it?

CR
Old 09-18-2014, 06:39 AM
  #27606  
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This is the next C&H Ignition I want to use. As you can see it has a special cap molded onto it for the Maloney spark plug with its weird top end. The Synchro Spark is in the rectangular module you see, I believe it's all in at 2,500 not much room above idle. According to Terry Grant it has the ability to sense acceleration and can generate an advance curve. I tested it with the Maloney spark plug and it makes quite a crack when it sparks. It's from 1991.
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Old 09-18-2014, 06:43 AM
  #27607  
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Originally Posted by Charley View Post
Too bad you didn't try gas in the engine with the higher CR. Do you still have it?

CR
Gasoline use in a spark ignition air cooled engine is limited to about 9.5:1 CR to avoid detonation. That is how they are getting gas to fire W/a glow plug. Basically what you then have is (somewhat) controlled pre-ignition.

I fail to see the allure of running gas in GI (glow ignition) engines unless it us so small that CDI is not practical in the appropriate size airframe due to space limitations.

Last edited by SrTelemaster150; 09-18-2014 at 06:50 AM.
Old 09-18-2014, 06:48 AM
  #27608  
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Originally Posted by Hobbsy View Post
This is the next C&H Ignition I want to use. As you can see it has a special cap molded onto it for the Maloney spark plug with its weird top end. The Synchro Spark is in the rectangular module you see, I believe it's all in at 2,500 not much room above idle. According to Terry Grant it has the ability to sense acceleration and can generate an advance curve. I tested it with the Maloney spark plug and it makes quite a crack when it sparks. It's from 1991.
If it were me, I would try that on the 150 & use the later Synchrospark module on the smaller engines due to elevated idle speed in the smaller engines.

Your 150 should idle well below 2500. I think the later Synchrospark modules are all in at 4000 RPM.

Last edited by SrTelemaster150; 09-18-2014 at 07:06 AM.
Old 09-18-2014, 06:55 AM
  #27609  
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I'll hit Adrian up for one of the 120 degree plug clips and do that very thing.
Old 09-18-2014, 07:23 AM
  #27610  
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Old Fart- the biggest thing I've learned about tuning engines is that you have to take off and fly around the traffic pattern a few times and listen closely to the engine. It isn't really tuned until you do that. About half the time I have to land and richen the low speed need of a Saito just a tiny bit. But, if you do that and land every time you hear the engine sag, stumble, or run erratically the least little bit you will richen it to the just right point and that Saito will be the sweetest running engine you ever saw. I do the same on 2 strokes. Everybody forgets how important the low speed is on those engines too.
Old 09-18-2014, 07:30 AM
  #27611  
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Barry, you can bet safely every time that when someone complains about a Saito vibrating or getting poor fuel economy that the LS needle is too rich.
Old 09-18-2014, 07:32 AM
  #27612  
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Originally Posted by blw View Post
Old Fart- the biggest thing I've learned about tuning engines is that you have to take off and fly around the traffic pattern a few times and listen closely to the engine. It isn't really tuned until you do that. About half the time I have to land and richen the low speed need of a Saito just a tiny bit. But, if you do that and land every time you hear the engine sag, stumble, or run erratically the least little bit you will richen it to the just right point and that Saito will be the sweetest running engine you ever saw. I do the same on 2 strokes. Everybody forgets how important the low speed is on those engines too.
The 2-strokes are not as convenient to tune the low speed needle while the engine is running. You have to shut the engine down to avoid getting the screwdriver hit by the prop. It happened to me on my first engine, that made me jump.
Old 09-18-2014, 07:39 AM
  #27613  
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Originally Posted by AeroFinn View Post
Hsukari and blw

Thanks for your comments. 1/32 of a turn equals about 5 minutes? right? No way I can lean the engine that much it will die on acceleration. But to be honest I do not have any issues with 2300-2400 rpm idle as my pitch is 6" so I can slow down on landing nicely. I also think the Aerosave being extremely good with it's lubinq qualities the side effect is it takes a forever to get the engine run in. I mean, really run in.

So to sum up I think those people how say "I never or very seldom need to touch the needles of my engine" are those fellow modellers who are happy with good performing engines but do not expect their engines to run perfect every time on the field.

Any Saito should be able to idle reliably at 2000 to 2100 rpm on 15% and an APC prop. I just mention APCs because I'm used to them. My 125 has an APC 15x6 and it took a while to get it to idle where it should. I have a 72 that I've had set for 1900 rpm.

I disagree about tuning often. I had a 56 that I flew 2 years and never touched the needles. It ran like a Swiss watch every day, summer, winter, and everything in between. But, you have to have the low speed dead solid perfect to do that, imo. I also had my 72 set where I never thought of touching a needle when I got to the field. Just fill it up, crank it up, and go enjoy flying. I bought a used 91 from a guy on RCU and when I ran it on the bench I could tell that engine will probably run for years without ever tuning anything. The owner had it perfect.
Old 09-18-2014, 08:24 AM
  #27614  
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Good advise about the low speed spring on the .45, I will see if I can tweak the control rod to apply some pressure at idle and pull the rotor out some to keep it consistent. I will keep an open mind about it.
I still think the .62 has a main bearing that isn't seated and when the case heats up during flight it causes enough drag to make it die at less than full throttle but not enough to make it die at full throttle. I don't believe it is fuel system related , not when I can install the .45 in its place and it runs perfectly.
I called Horizon but they were unaware of any particular conditions to the .62 that would cause it.
Old 09-18-2014, 08:41 AM
  #27615  
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Originally Posted by jeffie8696 View Post
Good advise about the low speed spring on the .45, I will see if I can tweak the control rod to apply some pressure at idle and pull the rotor out some to keep it consistent. I will keep an open mind about it.
I still think the .62 has a main bearing that isn't seated and when the case heats up during flight it causes enough drag to make it die at less than full throttle but not enough to make it die at full throttle. I don't believe it is fuel system related , not when I can install the .45 in its place and it runs perfectly.
I called Horizon but they were unaware of any particular conditions to the .62 that would cause it.
Send it to me and I will put it through a LOOOOOONG flight test program. I have the plane just right for it,.
Old 09-18-2014, 10:06 AM
  #27616  
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[QUOTE=SrTelemaster150;11883146]Gasoline use in a spark ignition air cooled engine is limited to about 9.5:1 CR to avoid detonation. That is how they are getting gas to fire W/a glow plug. Basically what you then have is (somewhat) controlled pre-ignition.

Nuts. CR over 1:12 are common. It's all about the fuel.

CR

Last edited by Charley; 09-18-2014 at 10:09 AM.
Old 09-18-2014, 12:46 PM
  #27617  
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Originally Posted by Charley View Post

Nuts. CR over 1:12 are common. It's all about the fuel.

CR
.

You show me an air cooled, carbureted, 12:1 compression ratio 4-stroke engine, running on pump gas & I'll show you an engine that will detonate under load once it gets to operating temperature.


10.5:1 can be streetable IF the right cam specs keep cylinder pressure down until the revs climb. 12:1 in an air cooled engine W/O computer controlled electronic fuel injection & ignition on pump gas is just waiting to hammer the piston crowns.
Old 09-18-2014, 01:11 PM
  #27618  
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Originally Posted by SrTelemaster150 View Post
.

You show me an air cooled, carbureted, 12:1 compression ratio 4-stroke engine, running on pump gas & I'll show you an engine that will detonate under load once it gets to operating temperature.


10.5:1 can be streetable IF the right cam specs keep cylinder pressure down until the revs climb. 12:1 in an air cooled engine W/O computer controlled electronic fuel injection & ignition on pump gas is just waiting to hammer the piston crowns.
what if he's using low/no nitro and a super cold glowplug? theoretically speaking.
Old 09-18-2014, 02:47 PM
  #27619  
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On methanol in spark engines. Us O/t flyers here in Oz are always looking for "the advantage". To this end I have seen dry sumping of glo 4 strokes (more combustable liquid by volume, goes better) to an OK Super 60 with a steel liner and steel crank running on spark and ignition at 12,000rpm, yes that figure is right. I know of at least 12 that were made and my mate who acquired the one offered to me (who wants a "low reving spark ignition thing from the 30's) is still laughing to the winners circle. Runs around 15 to 20% nitro 20% synthetic (I tnink) and the rest methanol. Gets the long "antique" engine run, yes I've seen those things run on methanol and to think I helped him get the rule changed so they (sparkies) could run on methanol. No accounting huh.
Old 09-18-2014, 02:49 PM
  #27620  
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Old Fart, the comoing thing here re gas Saitos is the little ones and the radials, though there is a project in the wind (under construction) for a number of 57 gassers.
Old 09-18-2014, 03:33 PM
  #27621  
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I ran the 1.00 Saito equipped with the same C&H Ignition I ran on the 1.50, timing set at precisely 35 degrees btdc. I think the combination of 35 degrees and the 15% fuel is a bit much. It has a definite Diesel rattle above 7,000 rpm and at 9,700 with a Graupner 14x7 it unexpectedly kicked the prop off. On a second run with a ProZinger 15x6 it turned 9,500 and still had the knock/rattle. It sounds exactly like an over compressed Diesel conversion. I'll have to think tank with Dan. I did have to lean the LS needle about a half turn to get below 1,500 on the idle. The problem with the Hall Effect bracket I made is the only way to change the timing is to move the prop driver and it almost always moves itself after you've had it off. Thinking, thinking
Old 09-18-2014, 03:46 PM
  #27622  
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Originally Posted by hsukaria View Post
what if he's using low/no nitro and a super cold glowplug? theoretically speaking.


Originally Posted by SrTelemaster150 View Post
Gasoline use in a spark ignition air cooled engine is limited to about 9.5:1 CR to avoid detonation. That is how they are getting gas to fire W/a glow plug. Basically what you then have is (somewhat) controlled pre-ignition.

Please read my post above & note that I specifically referenced "spark ignition".

I have no interest in discussing the ludicrous practice of trying to convert a gas engine W/an efficient CDI system into a GI gas conundrum.

What's the point? Convert to a crude inefficient glow ignition set-up to save what, 4oz of weight?

Glow ignition has its place in small airframes were there isn't room for an ignition module & the weight might be a penalty. That's a pretty small airframe & the cost of what little bit of glow fuel an engine of that size would burn would be small.

In a gas fuel GI engine, the compression ratio would have to be high because, as I also stated, the engine would be operating on "somewhat controlled pre-ignition".

Methanol on the other hand can tolerate higher compression in a CDI fired engine because it resists detonation better than pump gas.
Old 09-18-2014, 03:58 PM
  #27623  
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Originally Posted by Hobbsy View Post
I ran the 1.00 Saito equipped with the same C&H Ignition I ran on the 1.50, timing set at precisely 35 degrees btdc. I think the combination of 35 degrees and the 15% fuel is a bit much. It has a definite Diesel rattle above 7,000 rpm and at 9,700 with a Graupner 14x7 it unexpectedly kicked the prop off. On a second run with a ProZinger 15x6 it turned 9,500 and still had the knock/rattle. It sounds exactly like an over compressed Diesel conversion. I'll have to think tank with Dan. I did have to lean the LS needle about a half turn to get below 1,500 on the idle. The problem with the Hall Effect bracket I made is the only way to change the timing is to move the prop driver and it almost always moves itself after you've had it off. Thinking, thinking
Get an adjustable ring for your magnet so you can play W/timing. Set the timing @ 35 BTDC on a prop hub that has been previously been on the engine while it ran. Mark the ring & prop hub for reference & move it about 1/6" either way to see what happens.

I also wonder if your fuel isn't contributing to your issues. I ran both 15% nitro/16% lube as well as 39% nitro/8% lube on the same 35 ignition advance. No issues at all & after Richening up the HSN fir the added nitro content the engine screamed, turning the 18 X 8 Dynathrust propeller @ 8850 RPM.

What percentage lube is your fuel? Could too much lube be causing the deiseling?
Old 09-18-2014, 04:00 PM
  #27624  
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It's WildCat 15% with 18% 80/20 syn/castor blend. I have been using it since 1991
Old 09-18-2014, 04:25 PM
  #27625  
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Originally Posted by Hobbsy View Post
It's WildCat 15% with 18% 80/20 syn/castor blend. I have been using it since 1991
But not W/CDI. You're playing a game that has slightly different rules now. I'm not saying that your fuel is bad, it just might be altering things a bit & require some tinkering. It Is a variable that needs to be considered.

Call Adrian, he will sell you just the magnet ring & hall sensor mount for your FA-100. He can supply you W/either a Futaba style connector or a DEAN connector. He might even have a mount sans hall sensor so you can JB Weld your own into it.

His website only lists a fraction of the things he has available & he has done scads of Saito engines of all sizes.

You need to play W/timing to get what works best for your combination.

When I'm working W/a new engine combo I mark the hub/ring & do the 1/16" adjustments either way. That amounts to about 2-3 depending on the diameter of the hub. I settle on the setting that gives me the best WOT performance & not a bit more. There is usually several degrees of advance beyond maximum performance that doesn't change anything. Find the exact point of best performance & leave it there. Another way to look at is to retard the timing until the performance sags & go back a few degrees advanced. Running at retarded ignition setting that degrades RPM is not a good thing, but you do not want to run anymore advance than necessary. After you establish your ideal advance setting, you can then go back & see exactly where your timing is W/the degree wheel.

My results W/single cylinder Saitos from 91 to 180 W/15% Cool Power have always shown that an advance setting between 34-36 BTDC has been the sweet spot W/the fuel I use. Now, as long as the initial setting between those values I just leave it.

Last edited by SrTelemaster150; 09-19-2014 at 02:24 AM. Reason: Typo correction

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