Saito 72 without battery dies instantly
 

Engine was working very well, then was on hold for two years.
Now is mounted on Tucano, upside down.
I am using new fuel. Motor has new OS F type glow plug.
I repeated carb adjustments from factory setup.
Motor dies instantly without power supply.
Please, what else can cause troubles?

Richen up the lsn setting and peak the hsn properly first.Then lean off the lsn so it will run without the glo stick and still have good transition,re check your max rpm using a tacho.If you go too lean on the lsn it will not give max rpm and may be lean there as well,you'll hear the engine sagging at max rpm,or it might not even get there.Store the plane so the glow plug does not get full of old oil between flight days.

99% of the time an engine dies when glow heat is removed the idle mixture is too rich. The other 1% of the time it's a bad glow plug. At least for me anyway. I don't own or run saito engines though so there might be a different trick to them. Maybe it needs more nitro?

Tim, trust me on this- you really need a Saito.

I agree that it could be too rich on the bottom end but I have seen either a plug being bad out of the package or if an engine has been sitting for a while it can have rust on any of the steel internals. Rust particles will take out a plug very quickly.

My buddy said something similar, told him the same thing; If I'm gonna have a 4-stroke, it will be an Enya. No interest in Saito whatsoever. Thanks for the suggestion though. I like using cheap fuel, Saitos don't like cheap fuel. Enyas will run on FAI fuel and will rev too - a 13,000rpm redline is impressive for a 1.20 IMO.

Thanks to all. I'll stick setup procedure letter by letter.

Actually 1Q, Saitos run perfectly well on 5% or 0% fuel, Europeans run them that way all the time.

It makes a guy wonder why everyone uses 20-30% in them then...? Nonetheless I still have no interest in buying one. I like living on the edge with my front facing glow plugs. ;)

I believe that stems from the fact that Saitos respond very well to high nitro, but they don't really need it. I am an Enya fan also although I am currently low on them, an old 1989 .46 MKII and a ? .45..

Yep, I have a couple of home made rigs to light Enya fourstroke plugs.

I made a homemade remote glow clip for my 60-4C until I broke down and got an Enya clip. The Sullivan remote clips wouldn't clip onto an OS F plug in an Enya with 1 washer, but worked okay with Enya 3 plugs. I've seen guys using short glow driver sticks to start Enyas but that is not smart. I much prefer the obscure and uncommon stuff, perhaps that's why I own and buy the engines that I like. Nobody runs that kind of stuff at the flying fields I've been to. I like to be different; I can't wait to see those guys' faces when I fire up my Fox twin.

I know you said you are using "new" fuel and a new plug but what you are describing is almost ALWAYS fixed by a new plug or fresh (dry), fuel. My guess is, is that you've got moisture in your fuel. The easy test is to borrow a tank of fuel from a buddy who's engine is running well.

Fuel will absorb a considerable amount of moisture without harming the running too much. Up to a point, you probably won't notice. Once it passes a certain threshold, the symptoms are the engine will start, idle, and run well but at random times simply shut off. It will then start right up again but a few moments after removing the glow starter, quit again. With yet a bit more moisture in the fuel the engine will run all day with the glow heater attached but shut off with it's removed.

Try some other fuel and another OS F. If that doesn't get it then start looking at tank, clunk, filter, pluming, mounting, valve, air leak, etc. problems.

Let us know what you find.


Cheers,

Bill

It could be all of the above or simply the fact that the carb was reset to "factory" settings, thus giving too much fuel for the engine to keep running without power to the glow plug...

The "factory" settings are only a recommendation at best. They are only there for everyone to get their engines started very rich for the first run or two, then the needles will have to come in.

I've gotten hold of a couple gallons of fuel during my RC career that weren't even good enough for charcoal starter! I've got a OS 91 that's doing just as you describe and the first thing I'm going to do is change fuel .... Been in that rodeo before and got the knots to prove it!

just wondering if you tried blowing it out (going full throttle for a few seconds) with the plug driver on and get the same result?

Sounds like it could be flooding during fueling. I had the same issue with an OS engine installed inverted. When you fuel the tank you could try clamping the tank to carb line which will prevent fuel flooding the carb.

Tom

If it dies instantly when the battery is removed then it is the plug. I run Saito engines inverted with out on board glow no problem. 20% nitro.

Agreed on the plug. A rich engine will still run. If the engine will run and make good power with the glow driver on, the mix is at least close to being right. The removal of glow plug heat causing the engine to die immediately usually means a bad glow plug.

Use an OS Type F plug. It is the best one out there for any 4 stroke. It solves many problems.

Hi,
Try turning the model "Upside-Down" with help from a buddy, start the engine and tune the high speed needle. slowly reduce the throttle down to idle and adjust the low end "IN" until the idle is smooth, then remove the Glow igniter. if the Idle RPMs go up a little, that should be a good setting. If you can't get a good idle with the engine upright, change the glow plug. What Else ? Rusty Crankshaft Bearings.

My Saito 72s run just fine on just about any fuel, new or old, 5%-30%, but the high nitro stuff costs more and I don't need it.

Ken AMA 1528

Yes, I also run ENYA four strokes. A very early .40, a few .46, .53, .60. .80 and a ENYA 120 R Gear Pump. And size for size, they do OUT-PERFORM my Saito and my OS engines.

Can you tell us how rust particles can take out a glow plug in a 4-cycle engine? I can't say I've heard of the valves rusting, but I suppose that'd be the only possibility?

The OS-f does not come in a box with a halo that says. "I'm the best" in a well adjusted engine the OS-f does nothing when swapped in to replace any other brand.

Remember to adjust the LS needle with the HS needle at full peak. The HS needle seat is fixed and is not influenced by the LS needle, by peaking the engine and temporarily leaving it peaked you have eliminated one variable.

My Saitos all have their original Saito plugs in them, and run like champs. Lots of hours on them, and very reliable with low idles. I do keep "F" plugs as spares, but haven't needed them in years.

That being said, I've seen many engines that ran perfectly when installed "upright", only to have this exact problem when installed inverted (no carb adjustments made).

The culprit almost always turns out to be fuel system geometry- if the engine is installed inverted, the carb ends up lower than tank centerline, causing a rich condition and possibly siphoning as well.


You can probably get it to run well enough with a re-tune, but if you have fuel system geometry issues you run a greater risk of dead-sticks. Lower your fuel tank so that the tank centerline = carb centerline and your engine will tune perfectly and be (most importantly) very reliable.

I think what you are trying to say is that there are alternatives to the OS F plug. While I would whole heartedly agree, I've never seen a four stroke where an OS F does not work. With that in mind, when people come to me with a problem engine, I ALWAYS tell 'em try any other fuel and a new OS F plug. This fixes 90% of the problems without ever turning a screw. I've seen folks at the field fight an engine for several weekends and when I look at their fuel jug, it's barely capped much less air tight. In Mississippi, that's a killer - FAST! And what could be simpler than changing a plug? Sure - sometimes we end up spending a day checking clunk lines or remounting the tank for a better location but I will tell you that that is a LOT harder than swapping fuel and plug.

If you have a good running engine, with a well sorted installation, go ahead and try 50 different plugs. It's educational, fun, and many may work well and have offer benefits such as greater reliability, lower cost or better availability; however, if you'd like to eliminate most problems in 180 seconds, dry fuel and OS F. Then go from there...

WJ, just don't forget that fresh fuel and a Fox Miracle plug will work too.:o