SWORDSN

My Feedback: (13)

I don't have pics,but he is running 20-1 oil and they were both installed in an open cowl,plenty of air ,situation. Both were older engines with many hours of run time.I will post more info as available.

AA5BY

I've now 43 flights (7 hrs) on a Saito 125a converted to gas, using the stock carb. Running 20:1 fuel mix.

w8ye

My Feedback: (16)

+1

acdii

So you have the glow carb on it, and not having issues with the seals?

AA5BY

Not so far.

acdii

Been considering adding CH to my 125 in my Mustang, converting to gas without the need for a new carb is a plus. $125 for the 125.

AA5BY

The only thing I needed to do beyond installing the ignition is to provide a throttle servo speed slow down.

acdii

I can do that through my radio. Neat trick too, use it for deploying flaps.

forrest gump

Hello all.Now I have just bought one of these engines brand new but 2nd hand to me(BNIB)I have read nearly every post of the 73 pages and it had made me think.I wonder if running them in on methanol(glow fuel)would help the cooling and running in process.I.E just put a glow plug in and treat like a normal glow running in.I have run in hundreds of glow saito's with no issues and just thought it might help to settle down the engine before running on petrol.I intend to use Mobil 1 2t oil as I have been using it on a converted saito 72A for months now with good results.One other thought,if it does play up big time with spark plugs,ignition..etc.etc..I will just run it on glow forever..I know that is not the point but its my back up plan...What do you guys think?


P.S it was very cheap for BNIB so could spend some more money if required etc..etc..

acdii

Glow would destroy the carburetor. If you keep the ignition system and swap out to a glow carb, then you get more power and better fuel use, but trying to run it as is with a glow plug instead of the ignition will fail .

forrest gump

Ok,just wondered what the carb(diaphragm etc) was made of you see.If it was unaffected by methanol then it might work as the needles are still too sensitive ,even when supposed to be designed for petrol..weird really for Saito to do that.Yes I have read somewhere that you can run on glow with the spark plug and timing stuff on and it gives 5% more power,Ironically. ..That would be nice.As i said earlier I have converted a Saito 72a to petrol and its rips around in a Kyosho Calmato lowinger.It gives nearly 1.1HP instead of 1.2,or at least over 1hp so like a saito 62 really.All i did was make a gasket of about 0.4mm to put under the head and change the spray bar and needle valve to whats in a saito 14c and it tunes very well.Idles at 2200 and gives about 10200 on a 12.5x6 Bolly prop.Obviously its got a RCEXL ignition system and magnet ring/pickup etc..etc.. I have a saito 14c and fg-11,I have run the 14c and it goes well once I had re-learned the tuning for their petrol's as i learned from re- building the carb on the 72a that the idle needle drastically affects the top end tune at all times as the idle needle still covers the split in the spray bar where the fuel comes out of into the intake manifold.Once I had got this then the 14c purred like a kitten.I am ready to give the fg-20 a go but just got all sweaty from reading here!Maybe I should not have bothered reading and just done it.I have checked,my fg-20 has a new type spark plug in with no label,and a small center punch dot on the carb behind the fuel intake ,not where it shows on the pics here but maybe they put them in a few places..I hope so.

If the ignition plays up then i will get the RCEXL setup like on my 72A but I understand the hall sensor setup for the fg-20 has an offset sensor to allow for the 28deg timing BTDC that the RCEXL unit uses,unlike the original saito big bulky sensor...if I have read correctly.And if the carb fails I might get a proper petrol one ,or glow one and run it on glow...For the financially interested, i paid Ł145 for it, so about $188 for a BNIB Saito FG-20....we will see,fingers crossed....FG

forrest gump

So my main question is Why cant we use glow fuel on the saito petrol carb?When using tubing and tank bungs suitable for Petrol fuel ,you can use glow fuel on those with no issues.It usually only works one way round..don't use petrol on stuff made for glow...that's my point really...Does anyone definitely know what's in the saito petrol carb and whether glow fuel will kill it or not??

dr.tom

Hello,
I am wondering is it safe to run gf21 with straight stock pipe only, no bulky can muffler Part installed?
Since i fly the ngh38 4stroke and it is mentioned in Manual that with short straight pipe it gives more power and runs happier.

What about fg21?
no noise restriction problem

Thanks

acdii

Sure, just tune for it.

dr.tom

Thnx will try then and report

Received it at last.
Spark gap was double than spec, fixed, now it fires a much nicer arc.

Ignition is an rxcel one which is great,
no need for upgrade as I have seen some have done with old saito one to fix some problems...





before


after



And valve clearances were none, 0.
Tuned them but did also experience the needles falling out from rocker seats, as some have reported here.
Sure hope valves/springs wont float during operation since that may force needles to fall out (seat disengages from needle since spring is not putting pressure on it)

dr.tom

Works like Saito should work,
Flipped it a few times in reverse to prime it and it came alive.
Valve clearance are supposed to be 0, so adjusted them back to stock before starting.

Hand start, first run ever.

https://youtu.be/aTnkCfMrKE4

dr.tom

Flight test

​​​​​​

dr.tom

dr.tom

dr.tom

acdii

Interesting fuel lines, where or what did you use for a spring? I have something similar for the engine pods for my B-25 with FG-30's, but will need to modify them a bit to make them stronger as I have the throttle servo and ignition system also mounted to it.

dr.tom

Hi,
the coil is from HK,
https://hobbyking.com/en_us/spring-w...-couplers.html

can be stretched a lot to cover more fuel line if you only need it to prevent kinking and not full protection from tearing/rubbing if it does not contact anything. Nice thing.
Good luck with your setup

dr.tom

RobJD

Here is my Saito FG-20 story…



It’s spring 2023 and I just got a NIB Saito FG-20 from a fellow hobbyist. He had bought it a decade ago to go in a Unionville Hobby 8ft Radial Beaver that he never finished. I was very exited to check out a spark ignition gas fired 4 stroke.



After reading all the problems on the Internet forums, I considered selling it as NIB. I was looking for a reliable fuel fired engine for reliable winter flying. So one day I decided to break-in on a test stand and see what happens. I know the internet community has many warning of how difficult they can be to run and tune.



The break-in (per Saito instructions) went surprisingly well. I couldn’t believe how little gas it used, even at a rich setting. I fouled one plug, but otherwise OK. I installed it inverted in my my “beater” SIG Kadet Senior. The first two flights went well, but on my third flight it would not transition to mid or high speed. I played with the carb tuning to no affect. Now at home it would’t run smoothly on the ground. I changed plugs, took to the field a few more times, sometimes I didn’t even get in the air. Then a few days later it would run Ok on the ground. Not consistent. And always black soot coming out of the exhaust.



My assumption was carburetor problems. I dismantled the Saito carb and saw no issues. So I bought a Ryobi 30c 4 Stroke trimmer carb from Amazon. I made an intake manifold adapter to trial this out. It worked way better, no black soot. So I took it to the field twice. Both times I had to change plugs to keep in running smooth. At this point I was on my 5th plug! After one of the plug changes the engine ran like a Swiss watch. The lightbulb come on…. My problems were also ignition.



I took it home and ordered a Rcexl ignition from Aliexpress. I was able to install using the universal sensor mount, and drill and tap one additional hole in the crankcase to get 28deg BTDC. I also bought the alignment tool.



Off to the field this Sunday. Beautiful sunny winter day -10C(14F). Six 4-5 minute flights with no issues!!!!!!! Idle good, transition good, high speed good. No dead sticks. Sigh. Finally.



The manifold is a 3/8” ACR copper street 90 silver soldered to a brass plate.

Timbers

My Feedback: (3)

You are right the FG-20 had ignition problems, you will be better off with the newer ignition you just bought. Keep an eye out for burning up the exhaust valve seat in the head on the FG-20. I went through 3 heads on mine and finally gave up and went to the FG-21 which has pressed in valve seats. Haven't had a single problem and had about 8 gallons on that FG-21 before the cylinder (jug) ears broke off and the engine was junk. The new FG-21 that I just bought in 2023 has an updated head design with a beefier area around the screws that hold the cylinder on to fix this issue.

There are plenty of people I have heard with FG-20s that didn't burn up exhaust valve seats like I did so good luck to you!