mike early

If the carb is closed, does fuel still run freely through it? If I am fueling a Tee fitting in the fuel line, do I need to pinch the carb line to avoid flooding?

Hobbsy

My Feedback: (102)

Mike, you got me there, if it did, I did not notice it, very few carbs leak fuel at idle though.

w8ye

My Feedback: (16)

The usual practice is to still pinch the fuel line on the carb side of the Tee

mike early

Well, I had planned on a 3-line tank, as there is no access to the fuel lines inside the cowling. I'll be using two clunks and a line from the pressure fitting on the flex pipe to the 3rd line on the tank

sertac74

Hello, i have test fly my saito 125 with showtime.Last weekend. I fine tune the engines low and high valves and fly the plane. Flys smoothly but i feel the engine is under powered . When trying vertical climb plane goes about 10 meters up and the rev starts to decrease then plane drops.. There should be some tune problems i think. I dont whant to think the total power of 125 ends there , it should go better. What do you think about when climbing rev starts to decrease then lost of power.

I also have the fuel in the tank is black after flying.(orginally redish) I know the presure line press the burned oil to the tank but is it normal the output of the burned fuel black oils. When flying engine has too little smoke out from mufler. Sometimes it is not visible, but black oils come out to body of the plane and to inside of fuel tank.

w8ye

My Feedback: (16)

3 lines will be better

w8ye

My Feedback: (16)

The Saito 125's needles are not adjusted correctly. The engine is going lean.

Ypu need to share more information like what prop and fuel you are using?

mike early

You say this from the performance (or lack thereof), or the blackness in the fuel tank?

richlloyd914

sertac 74,

Do you have the pressure line to the tank connected to the muffler or the crankcase of the engine?? If connected to the muffler it should not turn the fuel black. If the pressure line is connected to the engine crankcase it could turn the fuel black.. It should be connected from the tap on the muffler to the tank.

w8ye is probably correct about the mixture. Sounds as if you have the HSNV set too lean. Set the HSNV to maximum rpm and then richen, that is open, the HSNV for a 300 to 500 rpm drop. Do this at FULL-THROTTLE only. NOTE: if the pressure line is from the crankcase vent, correct that first and then re-check the HSNV and LSNV.

A well-tuned Saito will not smoke too much when running. It will not leave a thick, readily visible trail when in the air.

w8ye is also correct...post more information on fuel and propeller.

rlmcnii on richlloyd914's computer.

rexracer

If the pressure tap on your 125's muffler is on the bottom when the plane is level, it will blow more oil into the tank. Try to adjust the muffler so the pressure tap is on top. It would help if we knew your fuel tank location also.

w8ye

My Feedback: (16)

I'm with rimcnii and rex on this one

Biggles2

Can anyone tell me where I can get a selection of spare parts for my saito 100. Horizon in the uk dont sell them and horizon in the USA will not send them to the uk. []

w8ye

My Feedback: (16)

www.justengines.unseen.org in UK

Capt Lou

Rich:

I need clarification regarding you statement that a "well-tuned Saito will not smoke much when running ...and not leave a thick readily visible trail in the air". I have a Saito 91 on a Four Star 60, turning a 13x8 prop. I use Cool Power 30% heli fuel and believe that I have the needle valve adjusted properly at both the high and low speed. The engine has about 2-3 gallons of fuel burned through it and runs great. However, when I start and run at idle, there is visible smoke coming out of the exhaust. When I fly it, you can see a visible trail in the air from the exhaust. A fellow RC'r who is really knowledgable about engines, tells me that the smoke at idle and trail in the air is good. Am I doing something wrong? I know that Cool Power has a higher concentration of oil and this may be the cause of my exhaust condition. What are your thought on this? Thanks in advance.

Yaniel

i believe heli fuel smokes more than airplane fuel due to a higher oil level. i could be wrong though.

rexracer

I have to agree with Yaniel on this one. My Saito's don't smoke much when adjusted right, but I'm using 15% with 18% total oil content. Some of the heli fuels have 22-23% oil, maybe more. An interestin aside, though I don't know that it necessarily relates to these engines. Kevin Cameron (motorcycle guru) was talking about guys siezing on the high banks of Daytona running 2 strokes back in the day, and mentioned that many times they would add more oil to the mix to prevent seizing. Keep in mind that on a 250cc bike at Daytona, they were running as lean as possible to get the most speed that they could. Well, after adding the extra oil, they'd go out and seize again. What they didn't realize was that by adding oil, they were leaning the mixture (more oil=less gas) I never forgot this simple, but little known fact. Something to keep in mind if you decide to add oil content to your fuel. The mixture will change.

Michaelh

My Feedback: (4)

Coolpower Heli 30/30

rlmcnii

My Feedback: (3)

Capt Lou,

I should have been more specific in my note to Sertac74. A well-tuned Saito will not leave much of a smoke trail when running on fuel with 18%, or less, oil content. I have almost no first-hand experience with the high-nitro, high-oil fuels and do not know if they would cause appreciably more smoke or not.

My only experience with those fuels was a little bit second-hand in that it did not involve a Saito or airplane owned by me. It was a Funtana with a Saito 1.00 running(very poorly) on heli fuel. It was smoking very noticeably and causing the owner no little unhappiness. It had been tuned by an engine guru and the LS needle was way too rich and was causing all the problems. After retuning, as I recall the LS was two plus turns rich, the owner was much happier, the Saito was using much less fuel, depositing much less residue on his airplane, and making a barely visible smoke trail. So, I guess in that one case, heli fuel did not cause a lot of smoke. In fact, the smoke trail was the confirming sign to my thinking that this fellow's 1.00 had not been properly tuned.

The smoke that comes out of these engines is just aerosolized, unburned fuel and oil. When running too rich there is just a lot of unburned fuel and and the excess oil carried in the unburned fuel. And more oil than necessary coming from the crankcase breather and making more of a mess than necessary on your airplane.

I am not saying they do not smoke at all. But, on the 18%-oil fuel one must look pretty closely to see the smoke.

Please do not consider me a modeling expert, but in my inexpert experience a lot of Saitos are being run while far out of tune.

My son-in-law (Richlloyd) flies at a large-club field in suburban DC. Nobody there will fly a Saito because everyone there knows that it is impossible to make one run correctly. Probably someone needs to read some of the many posts in this thread about tuning a Saito.

The .91s are nice engines. Mine flies in a Bruce Tharpe Flyin' King. Enjoy yours.

Capt Lou

Thank you for the response and clarification.

RPMcK

My Feedback: (1)

Can anyone tell me what exatly it the primary function of the crankcase breather nipple?

mike early

I would assume the nipple on the crankcase is merely there to help route the blow-by oil away from the engine/plane. The crankcase needs to be vented to allow blow-by...which is how the bottom end of the engine is lubricated.

w8ye

My Feedback: (16)

there is a significant positive-negative constantly changing pressure in the crankcase. The crankcase must be allowed to breathe

thrashin

Hi Guys,

I have a troublesome Saito 72 and I really need some help! Always ran like clockwork (had it for about 2 years, flown about 30-40 times??), but recently has been giving me trouble on the idle. It's mounted on it's side and whenever I pull the glow off after starting, she dies pretty suddenly. After adjusting the idle mixture by richening it up (I know, doesn;t souns right, does it?), it at least idles for about 10 seconds or so, but then "loads up" and quits. It seems too rich (pinch test, smokey exhaust, raw fuel out exhaust).. so I lean out the idle (1/8 turn at a time) and it goes from running rich to too lean and dying. The other strange thing is that when I have it idling, with glow on, and I adjust the high speed needle, this alters the idle RPM markedly, My understanding is that this should not really happen.

I get the same results on the test bench as I do in the plane, although I thought I sorted it out last weekend on the bench.. it idled "hands off" ok for maybe a min or more, but it was VERY rich and rough.. spitting raw fuel out etc @ around 3500rpm, which was the lowest I could go, but didn't have to leave the glow on. I run Coolpower synthetic 20% with 10% nitro.

I have tried new & diff brands of glow plugs as well as a tank of a mate's fuel to make sure my mix wasn't bad. I am also going to check valve clearance just in case that has altered since last check about 3 months ago.

I have other Saitos and generally can get them dialled in ok.. but this one is driving me to distraction. I don't want to let it beat me but I have wasted two Saturday's at the field farking around with and I need some ideas.

I also have another .72, so I might swap it out and at least get my bipe in the air and sort this troublesome .72 on the bench. Also thinking of swapping over the carbies to see if that sorts things out.

So... anyone got any ideas?

w8ye

My Feedback: (16)

There has been a problem with 72's and the intake manifold leaking at the head junction.

To test for this see if you can move your intake manifold in and out of the head. The original design back plate was weak and allowed the carb/intake manifold to flex.

When the Saito 82 came out, it had a new design back plate with reinforcements for the carb mounting pad. However, it was the 72 back plate second design. It fits either engine but still carries the 72 part number.

Also it helps to have washers under the screw heads on the back plate to crankcase bolts.

You will probably need a new back plate and a carburetor O-ring set. Put new O-rings on each end of the intake manifold. The O-ring marked "Viton" goes into the head joint. The white washer was part of the original choke assembly and is not used.

RPMcK

My Feedback: (1)

w8y3 Then I am assuming from what you say that the main purpose of the breather nipple is to vent the crankcase, not to eliminate the excess oil. The oil being expelled is a side effect. I guess my next question is how much unburned oil is being expelled as a side effect?
Would it be possible to devise a air/oil seperator to contain the expelled oil rather than let it be ejected overboard. Could one use the in/out check valves used on the larger Saito engines for this sort of thing and would it be worth the effort in terms of reducing oil contaminatiom of the airframe?