I have mounted a Saito 100 after reviewing a few posts on the subject. I am having a little bit of an issue with it bogging down at low idle and then it quits.

Is this an issue of needing glow heat at low idle or is it more the low idle setting?

From what I had gathered from the other information that I had received, guys were running these inverted with out any issues at all and without any on board glow heat.

It is directly inverted as well, cylinder straight down, could that be a problem.

Thanks for any help.

I have the same engine in a Swallow ex90 mounted inverted with no real problems, and no onboard glow. My fuel tank is over the COG (back quite a ways) so I have a Perry pump to help out. I have tried to run OS engines inverted with NO success.

Where is you fuel tank? How far away is it? How high is it in relation to your engine? Check for fuel line leaks and connections.

Soooooo many factors!!!

The fuel tank is just behind the firewall, very close in fact, it is on a Goldberg Extra 300. Where the lines exit the tank and firewall, it would be above the carb and muffler.

High end runs good, low end seems to be the issue.

How much run time does the engine have? Have you adjusted the low end since you first ran the engine? I have a Saito 100 inverted and yes when it was new it stalled at low idle. I leaned the end a tad after running 3 tans through it and now it purrs like a kitten with very quick throttle response. Your Saito will run very well after about 10 tanks run through it.

Oh Yeah, one more thing, after you have a few tanks through it take out the plug the motor came with and throw it away. Install an OS F plug. You'll be set.

I have about 4 legitimate tanks through it. The first one I would not say was very effective as it mostly blew out the muffler cause it was so rich.

I am seeing a lot on siphoning problems with tank location and such.

I have adjusted the low idle valve to lean it. Still not quite idleing low enough and eventually just quits. I am seeing a lot that these seem to get better as you go, hopefully that helps as well.

I do have an os f plug, I may need to get it in there.

Tricktrack,
Definitely put in an OS "F" plug. The idle will get better after about a gallon of fuel has been through it but it sounds as though you may be a little too rich on the low end yet and/or possibly trying for too low of an idle. Don't go below about 2300 rpms at idle until it's fully broken in.

I run a Saito 100 inverted in a Pica Spitfire and never have a problem. It sounds like your tank position is too high. Any fuel dripping out when the engine stops?

Use the pinch method to determine if your low end is to rich. After about a dozen tanks through mine I'm still adjusting mine. Remember to move the low end needle an 1/8 of a turn at a time.

I'm also inverting a Saito 100, however, it's going in an EAA bipe. Per the instructions, Saito says to have the tank 4mm (talk about precision!) lower than the carb. Sounds like the problem could be solved by dropping the tank a bit. I've just run two tanks through mine and wow, this ain't no O.S. LA!

In looking at the tank in relation to the carb, the center of the tank is definitely higher than the carb.

I am extremely restricted on the ability to lower the tank due to lack of room in the compartment.

If I am not able to lower the tank enough, does anyone have any other solutions in lue of an on board glow ?

If you haven't tried to lower your low end needle, this is a good place to start. I have a 100 mounted inverted in a Cap 232 sport. I have about 5 gallons through it, and it now idles reliably at about 1800 RPM.I can make it idle lower than this, but 1800 is where I don't have any problems with the engine stalling. I would try leaning the low end needle, and then setting your idle as low as possible while remaining reliable. Fly the plane in this configuration. After a gallon or so, see if you can bring the idle down some more. Once these engines are fully broken in, they idle like a harley, even inverted.

Allan

I have leaned the low end some. From what I am gathering from everyone it may be just continue to adjust as I have been since I cant lower the tank and as it gets more broke in, continue to adjust the low end if it will to get a lower idle.

Correct?

Someone had mentioned running it without the muffler pressure. Is this correct or would that be for just testing?

The size and weight of the plane also plays a pat here. I have an inverted Saito 100 on my little WM P-51. Well being obviously way overpowered (intentional), Along with a 13/10 prop, My idle has to be so low that it borderline kills the engine. If its at a normal idle the plane wont sit still

As far as leaning the low end goes, this is what I did. Lower you throttle to a stable idle, being very careful(ie. plane and engine are not going to move under any circumstances) lean your low end needle 1/8 turn. If the engine RPM increase when you do this(this means your too rich on the low end), lower your throttle to a stable idle again, and again lean the low end needle. Check your transision to high speed between each leaning of the low end. Continue this process until you have your most reliable low RPM idle. You will probably have to readjust your high speed needle after you complete this process. Since this engine is new, I would adjust the high speed to about 400-600 RPM rich of peak RPM. This should keep everything well lubricated. After about a gallon and a half to 2 gallons, you can adjust your high end within 300 rich of peak RPM without any trouble. Also as I said before break in will greatly improve your idle.

Hope this helps

Allan