Hi all

I have a H9 1/4 scale Tayorcraft. I put a Saito 150 on it

The engine starts and idles just fine but when full throt
is applied it starts to act like its not getting enough fuel.

I had to put a one way check valve in line to keep the
fuel at the carb. The needle valve is above the tank.

I had to do it that way becouse the pitts muffler blocks
the needle valve.


Any ideas / suggestions

Thanks

Full Scale Pilot

I had the same problem with a 150 & a 180.

Felt like it was starving for fuel at high RPM'S.

I installed a Perry pump & gained prolly 2K rpm's.

Might try it.....

What size fuel line are you using? Just a thought.
Edwin

Im not sure what the size is.

What size should i be using on a saito 150

and if i need to go bigger. the brass tube that are in the
tank for pressure and the one the clunk is attached to will
be to smaill for the larger line wont it?

As you can tell this is my 1st giant plane.

sorry if these are stupid questions

Dave

That would be a cheap experiment. Maybe use small zip-ties to hold it on the tank. I've used medium on my saito 120. Havent fired up my 180 yet but I'll be using large fuel tubeing for it.
Edwin

I have 4 saito 150s and 2, 180s. I've used both med. and large tubing on the 150s and couldn't tell the difference. The 180's definitely get more fuel and run better with large fuel tubing. You have to drill out the clunk and use larger brass tubing into the tank as well.

I don't really have an answer to your question though. I've always used the standard muffler that came with the motor and I've never had a problem with any of them starving for fuel. You might make sure the muffler pressure line isn't clogged any where. Also stick a pin or small allen wrench up the nipple inside the muffler and make sure that's not plugged. It sounds like you might not be getting enough muffler pressure to pressure the tank. Jim

I have 2 180's and use the fact set up. Warning,, some of the mufflers with the pressure tap at the exhaust end of the muffler are known to vibrate out while flying. This will cause the engine to quit. I have one that has not failed yet, but I never put any pressue on it other than fuel tubing.

You didn't say what fuel, plug you are using. I use OSF and 15% cool power. I have also used the plug that came with the engine. They seem to work well now, earlier ones did not idle well. Check your top end rpm with a tach. Lean the mixture to peak rpm,, then drop it 300 rpm and try it out.. Jim

Sounds like you set your idle mixture with the high speed needle too rich. Open up your idle 1/4 turn and see if you can get it to run at high speed?

The high speed should be initially set with the idle rich. They will interact so you have to keep going back and forth peaking each one. When you get done, the thing will quit on you when you try to give it the gas. You have to go back and try the idle a little richer 1/8 turn at a time to get it to accelerate.

Good luck,

Jim

I had to put a Perry Pump on mine. I solved my problems

you should not have to put a pump of any kind on a Saito. Richen up the lower end and get rpm on the top end . go to idle for few seconds, then give full throtle if it spits and sputters lean the lower end an1/8 of turn and try again, if it quits, richen it up , after you set the lower end you will always have to reset the top end ....hope this helps

I'm have trouble with my 150 too. When it is on the ground it sound fine and when i'm flying level is sounds fine also. But when I go into a tough climb or a loop it bogs down (either runs out of fuel or too much) then quits.

please help me

"The needle valve is above the tank. "

Can you move the engine or tank so the needle valve is at the same height as the center of the tank?

jschwenk, The symptoms you're describing sounds like you may be too lean on your top end.

[sm=thumbup.gif]

Open the needle up. The symptoms are clearly too lean. You are probably lucky you haven't thrown a prop yet.
Just get gutsy and open the needle up about 2 or 3 clicks and try again.

I tried opening the valve on the hight speed and low speed and it throws props now. My hight speed is now at 5 turns out and the throttle transitions are good and it also holds a steady idle. I really can't move the take up higher or the engine down. Would a fuel pump solve this problem, if so what kind should i get?

I also tried changing the glow plug and changing fuel lines. I looked over the fuel take it still looks fine.

thanks

If it is throwing prop, its not getting enough fuel for some reason or another?

saito engines will transition quite nicely even when running rich. Being too rich on the carb will wet the glow plug and kill the engine suddenly @ low rpms and throw the prop if not secured correctly. 5 turns out sounds too much to me. Im running my saitos nearly 1 - 3/4 turns out at sea level on very humid and hot days.

I have 2 saito 150s . One is in a 1/4 scale Citabria with a slimline pitts. The engine is mounted horizontally(sideways) so I have no issues with the fuel tank. I just checked my needle setting and it's at 4 and almost 1/4 turns open with a Mejlic 18/6 prop. My other 150 is on a Golberg Sukhoi with the fuel tank over the c.g.(about 7 or 8 inches away from the engine) Therefore I wanted/needed a pump (Perry 4-stroke). I have to run the pump WIDE open to get it rich enough. It runs fantastic with the pump but took me awhile to figure out the pump needed to be wide open. In fact I had to modify the pump mount to get it out furthur from the centerline so it could occillate more. Not sure but I think that check valve and tank position may have something to do with your problem.

Do you use a tac? If so lean it to where the rpm quits increasing, then open the needle until you drop around 250 rpm.
IF this doesn't work you might have trash in the needle/seat area on the carb. You might have to disassemble the carb and clean it.
Also Are your valves set properly?

I is at about 9000 rpm with a 16x 8 prop. The tank is about 2 inches away from the engine and about 2 inches lower. I'm kinda thinking that a fuel pump would work the way you guys say it. Should i go with a perry pump and how does it pressurize the fuel (do you plug it into a battery?) How much would a pump help? What would one cost? Would you still use back pressure from the muffler?

I have a saito 72 engine and it runs perfect, so i don't think tuning is my complete problem.

The help is really appreciated!!

I have no fuel pumps on my saito's 1.8 (2) and the tanks are much further than 2" with no problem\


You have a fuel delivery issue. Hole in fuel tank fuel line from clunk to tube or one of the lines or the carb has trash.

I think a pump will add to your problems.

9300 is about what I get peaked with an APC 16/8. You're in the ballpark.

hi guys I have a 120 Saito at first time this engine disappointed to me, because y was buyed to replace a Magnun 91 in a Cap 232 TNTmodels, and the Saito moved the same prop at the same rpm but with some moore $$$$. So in search for the solution i dissasemble the engine and oh!!
The camshaft was moved to the point, Then i reassemble taking care abaut the point and the Saito became in a brute powe machine. Good luck

My Saito 150 was damaged and sent to Horizon, the repair costs were higher than I was willing to pay so I got a new one. The new one exhibited the same exact symptoms described, it died as soon as it reached half throttle. Every one of the experts at my field, which by the way I trust, tried every thing they could think of. The adjustments to the needles, cleaning the carb, changing tank pressure, size of fuel lines... nothing worked. One of the guys suggested I try the old carb and bingo the new engine runs perfectly fine. BTW, no adjusments were needed on the old carb other than the high end.

There seems to be a pattern here, it could be a batch of defective carbs. I am going to contact Horizon to see if they will replace the carb...

Maybe disassembling the carb will let you find out if there is trash in it.