Saito 125 low power

[CAT3408]

I have a Saito 125 with about two gallons of fuel thru it and the power is good for about ten sec and then rpm drops about 500 or more. Is has been this way sinse new but it seem to get worse now.
When I hover the plane the engine seems to get lean and looses power.

I have tried many different settings for the needle, fuel is 20% nitro 20% klotz 200, valve clearence is good, plug is Os F and i tried a new one.
Anyone has an idea ?

[Rush7]

If this is happening around high end only I would look for an air leak around the high end needle.
If this is happening during both the high end and low end then I would look for an air leak arounf the carb.

[Unbalanced]

Could be a sliver of trash in the needle valve restricting flow.

[jamesrxx951]

double check all your fuel lines and tank for any possible air leak. i had a 150 that did the same thing in a hover and i replumbed the tank and even changed the tank. put a perry pump in it and it became a new animal. install a perry pump and you will never look back. i just don't think you get enough back pressure with those stock mufflers.

[WangoTango]

Our friend Doug had this problem and after trying everything we found the backplate had some pits on the machined surface that fit against the crankcase. This was the leak that caused his sag in RPMs. With a new one, the problem went away.
WT

[jamesrxx951]

did he notice any fuel/oil leaking out of the back. if it was pitted i would think you would see leaking fuel/oil. i also installed a perry pump in my saito100 also huge difference in power.

[SunDevilPilot1]

Another thing you can do is check the temp of the motor when you bring it down. The hotter it gets the less power you will have.

SunDevilPilot

[WangoTango]

	Quote: Originally Posted by jamesrxx951
	did he notice any fuel/oil leaking out of the back. if it was pitted i would think you would see leaking fuel/oil. i also installed a perry pump in my saito100 also huge difference in power.

That was the funny part of it all........... Very little leakage.
WT

[wecoyote]

Is your engine inside a cowl? If so is it getting good air flow?

[CAT3408]

Thanks for many good tips ! I will check a few things and let you know what i find.
Yes the engine is in a cowl, or what´s left of it after i cut the very large holes for cooling... Plane is H9 Showtime 90.
No trash in the needle and tank already replumbed.
The Perry pump sounds interresting i´ll check if i can find one.

[tech8]

I have a Saito 180 with the same issue, it loses power after the first 5 min of flight, defenitly loosing power and going lean. I re-plumbed the tank and tht didnt help. It's wierd the low speed needle has to be set super rich for proper transition. I have a pitts muffler on it and suspect the back pressure is not what the carb is designed for. I might try the stock muffler. I tried a perry pump and it pissed out half the tank of 30% while starting it. I have heard something about putting a "T" inline before the carb on the feed line, this will allow excess pressure to run back into the tank. I'll update if I find the problem. hmmmmm how about a DL30 that'l fix it

[jamesrxx951]

how did it piss out half a tank? was it a electric pump or the vibration pump? i always use the vibration pump on mine. and the carb was lower than the tank but i fill then fly so it don't leak out and it will do that even if you don't have a pump. i have one saito inverted well below the tank and no issues at all.

[Dewayne Vaughn]

perry pumps operate off of engine vibrations, they mount to the firewall and must be in the plane of engine rotation to work. they are also fully adjustable so you can use them on various engine sizes. They wont waste fuel if they are adjusted first. Bought my first one twenty years ago.... probably fuy my next one soon....
Tower sells 'em. Read the directions that come with it and your problem will go away.

Luck, Dewayne

[AHP]

I've had great success with a Cline regulator on both a Saito .82 (ran great without it, but wanted the tank on the CG) and a Saito 125. The 125 ran fine without it (also on a Showtime), but it ran stronger and more consistently with it. One thing I've found with both of my Saitos is they will run fine with the needle settings way out of wack -- like super rich on the low and super lean on the high and vice versa. It's not until you get the needles 'right' that it will run stronger and more consistently, though.

FWIW, I exclusively ran Wildcat Curtis Youngblood 30/23. I've been out of the glow game for a few years, so I'm not sure if it's still available. Great stuff, though!

[CAT3408]

I took the engine apart and found nothing wrong with it, only one little pit in the cylinder wall but I don´t think that is causing the problem. It looks like a small black dot but i can feel it with the tip of a needle.
Piston looks good and bearings seems to be fine too.
I put it togeather and flew it and it has the same low power and runs unstable at full throttle.