retransit

My Feedback: (18)

Great, thanks for the info and the fast reply.

BTW, I have a .45 Special. Would that have the same case size as the .40?

Hobbsy

My Feedback: (102)

Here they are side by side, virtually identical. I'm not sure where the .45 MKII fits in the scheme of things.

blw

My Feedback: (3)

Slats!- take out the screws that hold the carb to the engine, and pull the carb/manifold off of the engine. You can rotate the carb and reattach. Insert the manifold pipe gently back in as there is an O ring it could nick.

Wolflord

Hi all,
I am having problems with my Saito 80 GK engine not staying running. I had it in the air for about 4 mins and then it died. I have been trying to keep it a little rich and have the valve at 2 and a half turns out. Not sure about the low end valve. Last weekend it made two flight and did not have any problems, but I did notice that I had my throttle cable hooked up in such a way that I was only getting half throttle. I have since fixed my throttle cable so it opens all the way.

I am running a 13X6 APC prop and morgan's cool power 4 stroke fuel. I bought the engine used and this is the second weekend I have used this engine. It is in a new airframe (Tiger 60 ) with a 16 oz fuel tank.

Any ideas what could be the problem?

Ernie Misner

If you run them inverted does the "top end" get better lubrication?

thanks,

Ernie

Ernie Misner

Hi Guys, a friend at the field has a Saito FG 20 gaser (125) and he says it runs lean at midrange but idles great and full throttle is great. He is getting some air bubbles in the fuel line and I suggested he find a way to eliminate that..... but I'm at a loss why the top end would be okay.

How does that gas carb work? Is there a diaphram in them? There seems to be no tank pressure whatsoever since it is vented to the atmosphere.

Thanks for any info....

Ernie

w8ye

My Feedback: (16)

The carb has a weak pump in it

w8ye

My Feedback: (16)

Yes

w8ye

My Feedback: (16)

You need to give us a little more information.

All I can think of right off is that maybe that it is not rich enough

jb86

My Feedback: (8)

I was hoping to get a little help
I've got .72 and .82 (and 1.00 but no issue currently)
niether run much, only a little on stand just to check performance
bought .72 used
just replaced bearings in both (had some noticeable corrosion)
both run great
I want to put the .72 on my ucando .46. Currently os70fs- max 10,000 w/apc 14x4w
I tested saito .72 w/ same prop
I had to richen / hold back throttle to limit 10k
it has more power than os 70fs and 5oz lighter!
My issue
I have run it a few times no problem starts easily
I generally "back flip" it
tonight it kept running backwards when I did
so I put the starter on it and started fine
got it running
warmed up with MA 14x4
stopped to change prop to MA 15x4
wouldn't start with starter
prime and back flip
it would kick
but not run
then electric starter
it would spin and spin
but not start
check plug
it glowed
needle 2.5 turns out
then spun with starter for about 20 seconds
it started
runs perfect thru full throttle range
why?
All 3 saitos I started a few weeks ago back flip
darn iPhone
I just inserted a line and can't get back down 2 lines!
So my last issue is with glow plugs
I run these engines rich while breaking in and on test stand to cool engine
the rich running seems to kill the glow plugs in just a couple of runs
is it possible to clean them with alcohol? I find an engine impossible to start after a couple rich runs but new plug it starts right up
I have always trusted saito/h9 plugs for saito and os f for os
but now the saito are $10ea!
Which is the best choice for saito?

one after another
glow plugs rich

w8ye

My Feedback: (16)

OS F is the best for all four strokes

jb86

My Feedback: (8)

thanks for that reply

i was hoping to just stock up on only one glow plug, i.e.; the os F. it is also a few pennies cheaper.

glow plug technology is a science i have never been able to completely understand. i just know what seems to work where.
jon

w8ye

My Feedback: (16)

me too

mike109

G'day

I have about a dozen Saitos at the moment. I have had one of them for about 8 years. It is the only one that has ever needed a new plug and that was because I mixed up the Plug and Starter connections on my power panel. Plugs don't like 12 Volts. I have not needed to replace any plugs in my other four strokes either for several years.

I don't know what is happening to your plugs but mine seem to last almost forever.

I use 10% nitro, 5% castor, 15% Klotz and the rest methanol. I mostly use 1.2 volt NiCd batteries for starter duties. And I always tune my engines slightly rich.

I have just run in my latest - an FA-40a. What a sweet little engine. 10 minutes rich at about 4000 rpm then 10 minutes richish at 6000rpm then set the idle adjustment for a good but not perfect idle then one more tank at about 8000 rpm and then into the air set a bit rich. No plug problems, no starting problems. When it has about an hour's running I will re-tune it for best results.

I have noticed with all engines that if you get them a bit hot they can then be hard to start. The fuel seems to evaporate (or perhaps it is because the hot running is because the engine is lean and there is just not enough fuel in there to let it start). If this happens, I find you need a prime to cool things down and to get the engine wet enough to start if it has been a bit hot.

Ernie Misner

>>> The carb has a weak pump in it >>>

I guess the Saito 125 gasser carb has a diaphram then? Perhaps it increases the suction from the tank slightly? It couldn't possibly make any pressure in the tank because the tank is vented to the atmosphere just like the old days before muffler pressure.

Thanks for any more info,

Ernie

Hobbsy

My Feedback: (102)

Hey Mikester, what prop did you run on the 40a, and is yours a GK, just curious. Thanks

Here my results from just a couple of days ago using WildCat 15% with 18% 80/20 syn/castor blend.

Saito .40a rpm====10,438 with Taipan 4c plug.
Idle rpm=========1,750
Switched to Fox Miracle
Max rpm========10,744
Idle rpm=========1,950


Read more: http://www.rcuniverse.com/forum/m_33...#ixzz0lduUlXoT

mike109

G'day Dave. I think it was a Bolly 11.5 x 5. I don't know what the RPM was but it provided plenty of thrust for the 57inch Tiger Moth. I had previously flown it with a Saito 30 and an old OS FS40. Both gave similar results though I think the 30 was better than the old 40.

To make the "muffler" fit inside the Tiger Moth's cowl, I am using one of the exhaust stubs from my Saito 90R3 on the FA-40a. It works perfectly and is not noisy at all. The resulting sound is very like the sound of a Gipsy Major engine when the Saito is at about 1/3 throttle and the Tiger is just puttering past.

I have two FA-40a engines and both are the standard silver model. The only black Saito I have is a 150S in a Four Star 120.

Tomorrow I am going to commit heresy and fly an OS engine! I bought an Alpha 81 at my local hobby shop when they were having a 30% off sale. I would not have bothered at full price. It is in a Hanger 9 Piper Pawnee and it is showing considerable promise swinging a Master Airscrew 14 x 6 very strongly. It does seem, however, to be quite heavy and bulky compared to the Saitos but perhaps I am imagining it.

I am also planning to fly my other FA-40a as well in its 80% size Astro Hog. It is an absolutely perfect match for the little Hog. I covered it in Sky Blue Monocote because it was very cheap and it looks great so long as I keep it close in. It just disappears into the "blue" if it gets too far out.

We are having one of your Indian Summers here at the moment. It is giving us the best flying weather we have had for months so I am making the most of it. Winter here is a bit of a non event though so we keep flying all year. Summer does get a bit hot though. 100 degrees F plus is quite common from December to March.

Cheers

Hobbsy

My Feedback: (102)

I left out that the prop I ran was a Bolly 10.5x6 so our prop load should be about identical, I love those Bolly's, I have yet to have to balance one.

spaceworm

Hi David, I noticed when you switched to the Miracle plug that although you picked up over 300 rpm on the top end, the idle speed jumped 200 rpm. Would it have idled at 1750 rpm with the Fox plug, and is the increase there just bettter firing efficiency? TIA

CU@WWRC

Sincerely,

Richard

w8ye

My Feedback: (16)

A heavier prop will idle at a lower rpm

Hobbsy

My Feedback: (102)

Richard, the Taipan plug is noticeably hotter than the Miracle plug, full throttle using the Taipan required a slightly richer mixture. The Taipan was better at idle than the Miracle plug. I would never idle an engine at either 1,950 or 1,750 when flying. I like 2,150 for flying.
It would idle at 1,750 on the Miracle but would die after about 15 seconds.

SU-31 flyer

Gas carbs are different. The Low needle feeds fuel all the time. So you set it first for a rich idle and a good transition ( mid range) then the hi needle. Then work both for best running. So when you change the low it does change the Hi needle. The Hi needle works the last 20%. Yes there is a pumping action that pulls the fuel.

w8ye

My Feedback: (16)

the Saito FG20 carb is made inside just like a glow Saito carb but it has a weak pump on the back side.

Ernie Misner

If there's a diaphram on the back side of that FG 20 carb where does it get it's pulsing pressure from? There's no line from muffler or backplate pressure and no direct hole into the crankcase like the Walbros have?

Thanks for the insight again,

Ernie

w8ye

My Feedback: (16)

On the G-20 and G-14

There's a hole in the barrel extending from the venturi area to the back side where the spring is.

There is a hole in the pump body alongside the diaphragm area that eventually gets to where the mylar diaphragm is. The diaphragm has a spring return because the is no pressure in the venturi - just vacuum pulses.