Hobbsy

My Feedback: (102)

That is the reverse from the norm, lower nitro % fuel usually runs at a leaner setting.

SrTelemaster150

I have never run anything less than 15% nitro yet. I live in a semi-rural area far from any large cities do fuel selection is limited. I do plan on experimenting W/0% nitro and lower lube % W/CDI when I can get a shippment of straight (unmixed) methanol, lube & nitro.

I did not see much difference between 15% & 30% nitro as far as idle & transition reliability however.

Your experience with GI and low % of nitro does seem like the opposite of the norm. That might be due to the low run time when you experienced the transition problems. That being said, with CDI, nitro content will not affect ignition timing like GI. Nitro content, other than needing differing needle settings due to the changing A/F ratio requirements, should not affect transition much W/CDI.

AeroFinn

Yes, it sounds strange. I think no conclusive results was achieved in my testing as the engine was under running-in phase. I will test the engine with 10% Aerosave and 5% nitro.

By the way, I don't get why the piston / liners would suffer of the lower oil content if YS CDI and Evolution radials are happy with 6-9% oil. The non-bushed connection rod may be an issue, I dunno. It's funny to read that some have had problems related to connecting rod failures with 20% oil in the fuel for some reason? Maybe due to a too tight fit of a connecting rod & crankpin in conjunction with failure to carry out running-in phase properly?

Anyways, I'm leaning towards thinking that the main thing is ensure the engine gets good cooling, i.e. a proper baffking arrangement s applied or the engine is exposed open to airflow without cowling.

It' seems the "old school" approach is to partly compensate inadequate cooling by having excess amount of oil in the fuel which is then thrown out of the exhaust to cool down the otherwise too hot running engine.

dmrcflyr2

My Feedback: (43)

So now that I have this engine running well, I need some suggestions of airplanes for it. I have a SIG Hog Bipe in the closet that I am considering installing it on. I looked for other videos of folks with this engine in an airplane so I could see how well it pulled it, but I was unable to find any. I think it would power an Astro Hog well, but I am not cutting the nose up on mine to install this engine. It needs to have an airplane specifically built for it. The instructions say up to an 8kg airplane.

https://www.youtube.com/watch?v=60o8pqQO_yw

https://www.youtube.com/watch?v=Y_FoYgOHlz0

https://www.youtube.com/watch?v=rivPNzoMkv8

SrTelemaster150

I think excess oil is also to compensate for the volatile ignition timing W/GI.

When GI is used, the A/F ratio will affect ignition timing resulting in a "double whammy" as far as detonation. Leaner mixture raises the combustion chamber temperature which leads to detonation, the ignition timing advances exaserbating the detonation conditions. I see the excess lube as an deterrent to pre-ignition as well as a coolant due to extra lubrication that might save an engine running lean on GI.

It would not surprise me to see 0% nitro, 10% lube W/CDI making power similar to GI W/10 or perhaps even 15% nitro and higher 16-20% lube content.

BTW, if you play with the ignition timing, make a "witness mark" on the prop drive hub and magnet ring for reference. Another 4-5° of advance will probably give you another 150-250 RpPM. Maybe not, but you should give it a try. I have never had any difference in idle/transition between 28 to 35° total advance. Even @ 35°, the timing is pulled back to 10° BTDC for starting & low/midrange. W/the slower flame propagation of methanol, it doesn't seem to affect the low end manners.

Still the FA-125 does seem to be the "odd duck" so YMMV.

FNQFLYER

Re the oil content thing that I raised. The wise people on this site do not repeat not ring their engines by running them lean (real lean) for max power. Less oil in any engine running at the top end of its performance envelope will result in damage. Saito set their oil content percentages for the "average" user, thus less warranty claims. Best example of this (if you need one) is the oil content (and type) and the troubles that eventuated with the introduction of the FG20. To be clear I am talking about standard glo type Saito 4 strokes here.

Hobbsy

My Feedback: (102)

I did an experiment a few years ago where I used 16% lube and 18% lube, running each blend about 30 minutes, at the end I pulled the backplate, in each case the same level of residual oil was in the crankcase. The logical conclusion is that the oil flow rate through the crankcase and vent is lower with the 16% package.
Picture #1 is an new and unrun 1.15, picture #2 is a well used 1.50.

Rudolph Hart

Or the oil level in the case while the engine is running is controlled by blowby pressure rather than the oil percentage you are feeding the engine?

Hobbsy

My Feedback: (102)

That's the conclusion I came to, I used to have an RCV .58 CD, RCV recommends 16% lube with some castor for the top bushing the cylinder turns in. I tried 18% in it, (you know me), oil poured out of that engine compared to 16% lube. I'd like to have another RCV some day.

p3arljam

My Feedback: (5)

I just mounted my first Saito i have been flyimg mostly O.S. 46 FX and 61 FX since i stated flying. I bought a used Saito 72 from a club member and another member tuned it for me on the bench at the field it ran really nice and smooth. I mounted inverted on a Decathlon (yes i made sure the center line is slight less then the carb). When i attach my glow igniter the engine cranks right up but as soon as i remove the igniter the engie dies. I have a new glow in it so my question is does this sound like the low speed is a little to rich and if so what is a good starting point?

Rudolph Hart

Pearljam that deccy will be fun to fly with the 72.Yes it sounds like the lsn is too rich,richen it up a bit more and leave the glo stick on if you need to at low rpm,then re check the main needle,try to peak the engine then back the main needle off two or three clicks,now adjust your lsn again.What prop are you running? i have a 46 size deccy with an 82 mounted similar to your 72,you're going to have a lot of fun flying that mate

p3arljam

My Feedback: (5)

Thanks for the response i am running a 12 x 8 prop. I have enjoyed putting this plane together i made an access hatch on the side for power switch charging jack and some other things. I will test the engine today and let you know how it went.

p3arljam

My Feedback: (5)

Ok now im frustrated i had everything ready to test and i used my starter and it just spun the prop the engine would not start. I removed the glow plug and connected it to my igniter and i got no glo so grabbed a new plug and tested it no glo again so i figured my igniter finally died on me(dubro kwik start) I had another igniter a friend had given me charged it up tested the plug i had nice orange glo. I started the plane it cranked up let it iidle with igniter left on no problems i advanced the throttle it died so i turned the low speed back out a little . I tried to start the engine again i got nothing tested 2 glow plugs no orange glo. I did notice some fuel drip from the muffler but not much anyone have any more ideas?

Hobbsy

My Feedback: (102)

If you really want this resolved, get the engine out of the plane, place it in a test stand upright. Is it broken in yet? If it is, start the engine, let it warm a couple of minutes and then go to full throttle, peak the High Speed needle at max rpm and leave it there, remove glow power, now reduce the throttle to lowest idle, (it might not be very low yet) and then procede to lean the LS needle and chase the throttle downward as the idle improves. You eliminate one variable by peaking the HS needle. Test the transition as Pete suggested , at some point it will hesitate when opening the throttle, back the LS out 1/8th turn.

p3arljam

My Feedback: (5)

Engine is broken in and was tested on the stand at the field and a friend of mine really good with engines set the needles for me about a month ago and the engine ran really nice. Tomorrow i am taking it to the field and he will be there to try and help me. I inverted the engine to save from butchering the cowl and i love how it came out but not happy its so hard to start. I read 2 things that might help as well . The first someone suggested to leave the fuel line disconnected and capped until right before i am ready to start the engine. The second was turning the vent line in the tank down instead of up for some reason many control line guys do this and they say it works for whatever reason.

Hobbsy

My Feedback: (102)

There is a learning curve to running them upside down, maybe that's why I don't do it. The only one I ever ran upside down was a PAW .40 Diesel in a Sig Rascal. The upside down settings should be very little different from the upright settings. Let us know what your guy suggest, Thanks

Rudolph Hart

Well did'nt you expect to be frustrated at first when you tune an inverted saito? the needle settings are the same as if it was upright on a test bench,your fuel tank is a bit high for easy priming and starting but once you throttle up and fly all is good.Unless you have done major surgery to the deccy fuse and lowered the fuel tank this is your problem,good luck.

dmrcflyr2

My Feedback: (43)

I have been on a roll this month. I was fortunate enough to find a NIB FA-90T MKII. It should be arriving next week. The great thing is that many of the parts are interchangeable with my 80T. These two engines cost me dearly though, but I am not complaining. The cost was selling the following: NIB OS FS-90, Enya 90-4C, Saito's 80, 65, 50, 30. Thinning the herd to make room for a few twins is an acceptable result. I still have plenty of Saitos and Enya's left.

Rudolph Hart

Thank god you got rid of the os's and enyas,you would'nt have a spare saito 125 lying around as well would you<they make a nice sound when they hit the bin too.

dmrcflyr2

My Feedback: (43)

No, I do not have a Saito 125. I actually love my Enya's and still have 4. AS far as the Saito's go, I usually run what I call the 'Classic' series of engines. I have the 45S, 45 MKII, 56, 65, 91S, and 80T. I really do not fly airplanes large enough to require larger than my 91. I did love my OS FS-90; it was about the only OS 4 stroke I ever really liked. I had 3 of them at one time. Fantastic running engines.

FNQFLYER

I also like my enyas. I have a 41 glo and a 41 diesel 4 stroke, great when I want to swap catagories but not models when flying o/t comp. I also have a "few" 2 strokes also mainly for competition. The only problem with them like Supre Tigres is the long run in time but fortunately that unlike the Cox 049s when they are run in they are great, coxes are usually run out just after they are run in.

Charley

My Feedback: (2)

You now have two dead glow-drivers. Charge them overnight & start over.

CR

p3arljam

My Feedback: (5)

Update both needles were off just a bit and my friend tuned the engine for me. Part of the problem was my charger is charging all my batteries saying they are full and they were not . So my glo igniter had almost no charge even though my charger said it was full. I charged 2 lipo batteries with the same result charger was showing charging and gave a full charge display . I checked my lipos with my battery checker and sure enough one only had 30% charge the other 60%. So my igniter never really charged and i was basically trying to start the engine on a dead igniter. A new charger is on the way and the Saito now is running smooth . Thanks for all the help.

Hobbsy

My Feedback: (102)

Good deal, I've never owned a LIPO battery, it seems as though every time I read about them someone is having a problem.

SrTelemaster150

Regarding running a Saito inverted.

2 things to watch.

1: Make sure the tank C/L is not significantly above the spray bar C/L
2: Most important, do not prime the engine, or do so sparingly. I have run an FA-150 as well as an FA-91S inverted with little difficulty. The FA-150 had the tank mounted over the wing centered on the CG. It was slightly below the spray bar C/L. I used a Perry oscillating pump in combo W/muffler pressure to supply fuel. The FA-91S was plumbed just as it normally would be for upright mounting. The Tank C/L was near the C/L of the spray bar.

Seldom will the needle setting that worked on the test stand be exactly the same as when the engine is mounted in the airframe. Especially if the engine is mounted in a different orientation as far as vertical/inverted. There can also be other variables that can be factors that may require some fine tuning once the engine is in its new home.