Uncas

My Feedback: (1)

I have a Saito 82 mounted inverted on new Reactor 46 which I just maidened. When I pull the power from my glow plug the engine immediately starts running rough and ultimately dies. I have tried leaning the low idle needle to no avail - well it eventually will not start. The carb sits about an inch below the tank. I can probably lower the tank a half inch, but not an inch. The fuel is new, the OS-F plug has been run twice maybe three times but it is a year old. Above idle it seems to run okay.

My question is will I need to use an on board glow ignitor? Sullivan looks like they have a nice one.

Will moving the tank be worth the effort if I have to buy the ignitor anyway?

Ernie Misner

Tuning will be a bit of a compromise with the carb lower, but it should be doable. It's a mystery why leaning the LS needle does not smooth out the idle just sitting there on the table. The problem would usually rear it's head when the tank is running low or inverted flight, etc.

Try setting and peaking the HS needle first, perhaps with just 1/2 tank of fuel. Then using the pinch test, keep leaning the LS needle a bit at a time until it idles smoother but is still rich enough to take the throttle when you punch it.

If you're running 15% nitro, try going to 20% which will give the needles more latitude.

Ernie Misner

Rv7garage

My Feedback: (10)

I'd still lower that tank as much as possible. Siphoning sucks ;D

If you do end up using an onboard glow, allow me to recommend the MPI unit. Excellent product.

freakingfast

My Feedback: (3)

Try a fresh glow plug first.
On some inverted engines, you can lower the tank or raise the nitro content and tweak the needles to no end and still you end up with too fast an idle speed or a dead engine on approach.
Don't fight a losing battle, get the on board glow.

Ernie Misner

Right on guys. Still there's a mystery about why he can't tune it for just sitting on the table without dying when the glow driver is removed.

Ernie

JariV

How about trying a hotter plug?

And another question; how much fuel through the engine? New, used, rebuilt?

Hobbsy

My Feedback: (102)

Unc, the LS needle controls the fuel mixture for about 85% of the throttle range. It has a huge effrect on the fuel economy or the lack of it. Adding an on board glow system to cover up poor tuning will only leave you with a fuel hog that still has a problem and a sluggish transition. I know I'm being a little light hearted but this is how I set up a potential inverted engine.[8D]

Sport_Pilot

I haver run inverted engines that are well below the tank.  You just have to lean out the low speed a lot.  And you have to clamp the fuel line after filling or start right away because the siphoning will flood the carb.  However a new 4 stroke can have an issue with excessive oil collecting on the plug.  If it idles fine when started at low speed or idle, transitions well, but have problems after a long run at full power then it could be from oil loading up in the crankcase, then pouring past the ring and flooding out the glow plug at idle.  This will usually go away once the engine is well broken in.  And I mean well like a couple of gallons past where you would usually consider it broken in.  Till then I recommend low nitro fuel (this is because the hgh nitro fuel runs richer and thus more oil pushed past the rings into the crankcase).  Also use all castor oil as the thicker oil will not drip past the rings as easily.  Also as hot plug as it will tolerate to burn that oil off before it floods the plug.  Once broken in you can try higher nitro, synthetick oil, and colder plugs.

Rudolph Hart

Hello dave and very funny.I had the same problem early on and found after a while that i had leaned off the lsn too much in an effort to keep the engine alive at low rpm while i9nverted(the engine,not the plane) as you and many other posters have said you can't over emphasize??(SP) correct needle settings for the max rpm and then do the lsn,works for mine.

Hobbsy

My Feedback: (102)

Hey, good morning OF, yeah, every time I see someone say that their HS will not richen to to pint of smoking you know that the LS needle is too lean. When the LS sleeve gets too far over the catseye not enough fuel can flow for full throttle. The sweet spot is just rich of that point.

Rocketman_

Uncas,

I agree with those who say that an on board glow battery is not required if the needle valves are set correctly.
What you described originally was a Saito .82 that was far too rich to idle without power to the glow plug then you adjusted the idle needle valve until it was too lean to start. Do you think maybe you missed the ideal setting by making your adjustments too large? Once it reaches the point where it won't start, try turning the idle needle valve CCW in very small increments (1/16 turn) until it will start.

I can't speak for OS 4-strokes but I know for sure that I've never had to use on board glow for Saito .72, .82, 1.00 or for YS 1.10 4-strokes, or any engine that I've owned for that matter.

You may have heard that the tanks are too high in the planes in picture 1 below but the UCD 46 has a Saito .72 and one of the UCD 60's has a Saito 1.00. The one in the foreground has an OS .91FX 2-stroke. Not picture here is the newest UCD 46 in the fleet that has a Saito 82. Pictures 2 and 3 show two YS 1.10 powered planes. As you can see all of the engines are inverted and all run flawlessly without on board glow. If they didn't run well I wouldn't be inclined to keep installing engines inverted.

Ernie Misner

>>> Hey, good morning OF, yeah, every time I see someone say that their HS will not richen to to pint of smoking you know that the LS needle is too lean >>>

Or they are running a pitts type muffler with very little backpressure and tank pressure. That might be more of a 2-stroke thing though.

Hobbsy, it looks like you inverted your whole test bench or workshop. Your wifey must be really wondering by now.

Ernie

Hobbsy

My Feedback: (102)

Ernie, I built the stand specifically for running engines, it has two 50 lb. solid cement blocks inside it. The PSP is bolted to the center of three 1/2x6x30" oak boards. I can bolt the oak part either way using two 1/4x4" soccket head screws that screw into 1/4" blind nuts. You can see the B&B Vibra-Loc hard rubber washers holding the PSP. My wife has wondered for a long time. She finds me, "interesting", I think in a good way.

Rudolph Hart

You could always liven things up by bolting a set of steerable wheels on it

Hobbsy

My Feedback: (102)

OF, I have actually considered bolting on a set of precision roller skate wheels in an attempt to measure thrust with it. I have the wheels. It would require some method of ancorage that would not inhibit its ability to pull on a scale and yet not take off. Thinking, thinking.

Ernie Misner

Hobbsy, put the roller skates on you and measure the pull required to accelerate your (m)ass up a predetermined local hill. Be sure to get an HD video recording because it would instantly go viral or make you some money on one of the lighter side sports channels if that throttle channel stuck WOT.

Ernie

JPMacG

My Feedback: (2)

I ran a Saito 72 inverted without onboard glow. It was a new engine, and at first I could not get a good idle. After several gallons of fuel it improved and eventually the idle became good. At the time I thought that being inverted was causing trouble, but I now think the engine just needed more breaking in. That model died in a rather spectacular mid-air collision, but the engine lives on, now mounted sideways in a GP Ultimate bipe.

Uncas

My Feedback: (1)

Thanks for all the help. I will try to tune it again and home in on a good spot to idle. The first time I attempted to tune I was pretty crude with my adjustments. I will also replace the glow plug.

For those that have asked, the engine used and broken in. It ran great last year in an OMP profile though it was side mounted.

To be honest at this point I am skeptical but hopeful. Taking the power off the glow plug had a pronounced effect on the idle. But if I can get it to run without, so much the better. I really do not want to side mount the engine.

Ernie Misner

Just a little more..... remember that once you get the bottom end leaned out if it still slows when removing the glow plug driver, that a little more nitro would help. If it wants to siphon fuel and drip while sitting on the table, make sure the throttle is closed all the way before you shut the power off to the plane, that helps. Better yet, flip your engine kill switch at the same time when you shut the plane power off and the carb will be totally closed.

Ernie Misner

Uncas

My Feedback: (1)

Replaced the plug - old plug looked new.
Leaned the needle about 1/16 turn
In the middle of filling the tank I ran out of fuel and filled the rest of the tank with newer fuel.

To my shock and surprise the engine ran fine and idled fine. No need for an on board glow ignitor.

While flying the plane, the fuel fill line came off the tank tubing. I have never had that happen before. Barely made a good landing. Guys at the field said on their YS engines they had to secure their tank lines. Is this a 4-stroke thing? Now I am putting barbs on my fuel lines...

The Reactor 46 seems to fly good but man is it nose heavy. Moved the battery as far back as I could into the fuse and added weight to the tail.

Hobbsy

My Feedback: (102)

Several of us have had YS engines over the years and we did not do anything special. I don't use any fuel line clips with a Cline or IronBay regulator and their check valve makes more pressure than a YS.

Ernie Misner

Usually the fuel lines will tend to come off if they are not secured or blowing in the breeze too much. Take your time routing them and use little 1/4 inch electrical clips screwed into key places or small zip ties to keep them neat and tidy if necessary. Make sure the diameter of the ends do not get stretched out with age and use new silicone tubing. Tower sells little spring clips if you do need them though. Barbs are more for soldering onto copper tubing.

Ernie Misner