old bird

Santa Claus was good here in Reno, I recieved a Saito FA.72 engine for my new plane. I installed it on Christmas day, and fired it up a couple of days later to start the break-in procedure. My question is, what is a good starting point for setting the high speed needle valve for initial starting and run. The book says that the needle valve should be backed out 2.5 turns. At that setting, using an electric starter, the engine was puking raw fuel out of the muffler, and would not start. I gradually closed the needle until the engine would run, but obviously rich, like missing and still sending out a lot of smoke and fuel blobs. I kept leaning it out a little at a time until it smoothed out a little. Ran it like that for 10 minutes and shut it down. I then checked the needle , it was out one and a quarter turns. One half of the recommended setting. Am I doing something wrong here, I would like to start leaning it out on the next runs. Temperature here was about 35 degrees that day. This is our first 4-stroke engine, so any advice is welcome. I'm thinking that the factory recomendation is wrong.

Regards from old bird.

William Robison

My Feedback: (3)

OB:

Give it another 20 to 30 minutes, keeping it a little rich, around 5000 rpm. And don't worry about the 2.5 turns, they usually have to be leaned a bit to keep running.

It should then be ready to fly, but don't lean it too much, and avoid long runs at full throttle until you have an hour or so time on the engine.

You will also find you'll have to lean the low speed a good bit, but don't worry about LS until the engine has at least a half hour on it.

When you have three or four hours total on it the engine should be able to hold both low and high needle settings.

Bill.

dinoslmn

My Feedback: (1)

Check this site
http://saito-engines.info/
Good explanation about break in and handle Saito engine

Ed_Moorman

My Feedback: (1)

You have to leave the battery on to keep it running at the very rich setting. Don't rush the break-in. The first couple of tanks should be at 4000 rpm-you'll have to throttle back. Mine started right up, then I backed the needle all the way off the threads and still had to throttle back. 2 tanks like this, then start leaning out a little each tank. I ran a half gallon through it this way.

Fuel. I used Omega 10% with extra castor added, 6 ounces to the half gallon. It's very sloppy.

After a half gallon on the bench, I adjust the valves and switch to regular Omega 10% for another gallon of air time. Then I go to 20%-25% all- synthetic heli or pattern fuel. You do need the castor for break-in and seating the ring.

I broke in a Saito .72, 2 Saito .91s and a Magnum .91 4s this way. The rings on all of them seated really well. They feel more like ABC engines than ring engines. Very snappy when you turn the prop over. The guys who thing they can skip a break-in have engines you can turn over with 1 finger and it's hard to tell where top dead center is.

Don't rush. Saitos take a long break-in, but last forever.

old bird

Everyone, thanks for the feedback. On my second run I left the power to the glow plug on and ran another 15 minutes on the extremely rich needle setting. I also purchased an RPM meter at the LHS, and this helped a lot. We had four more 10 minute runs, leaning the mixture a bit each time. It turned out that the low speed needle was extremely rich too, and may have caused the initial confusion as to settings at this altitude. It is 5000 feet at our field. I have one hour of run time on the engine now, and with a still slightly rich hi-speed needle setting it will hold around 8500 rpm with a 13-8 prop. Engine has very good compression, (subjective, no actual measurement), and will idle at around 2500 rpm. Weather conditions here in Reno are around 35 degrees and 75% humidity. After this last run session I readjusted the valves, the intake was a little loose, tightened the prop nut, and I hope we are ready to fly the new plane.

Regards to all and a Happy New Year, old bird.