Don41

I finally got around to firing up the two Saito engines I have had on the shelf for a few months. I started with the FA-56 and found it to be a piece of cake to break in. A whole LOT easier than my Saito FA-82a. It started instantly and I found no "rough" zones (I did with the 82).

Next came the FA-125a. The first three attempts left me with a loose prop from a backfire then on the fourth it ran (rather smoothly). I filled the tank and tried another run (same number of backfires and prop dodging before getting a start. Once again it started on the fourth and ran fairly smooth but not as well as the 56 did.

Enough rambling. I haven't owned an engine of the 125 size before. Does this sound about par for one this size?

I leaned the engine a little on the second run so I'm hoping it will start backfire free tomorrow. I also plan to remount the tank on my test stand. It is high enough that it allows fuel to run into the carb. It didn't bother the 56 or the 82 at all but that might be a problem for the 125?? BTW: Just before the second succesful run I spun the engine with glow on and fuel line disconnected then hooked up the supply and immediately hit it with the starter.

Any thoughts out there? I'm getting too old to dodge 16" props (:-).

Regards

PoormansACE

If your dodging props, it sounds like you may either be lean or you may have too much nitro for the 1.25. Some guys run 0% in these larger motors. pre-detonation is what causes your motor to "knock" and it will loosen a prop in a heartbeat. Just a reminder, but please dont run ANY motor up to full throttle while standing in front or beside it. I've seen a saito .56 go lean at wide open and the prop left the airplane and went flying by itself.

Don41

Thanks. The only time I am in front of my engine is to start it. At this stage it is definitely not set lean however your comment about fuel percentage strikes home. I'm using my usual Wildcat 20/20 even though Saito suggests 10 to 15% nitro. I'll see what else I have on the shelf,,, maybe pick up a lower mixture of nitro.

Regards

hrrcflyer

Don41,

I didn't have the problem you described when I broke in my Saito 125 and I also used 20/20 fuel. One thing you may want to check is the position of the low speed needle valve. It is supposed to come from the factory with the head of the screw almost flush with the throttle arm which was confirmed when I asked the guru's in the engine forum here on RCU. The reason I'm bringing this up is that I have a Saito 180 that was new in the box and the low speed needle was screwed all the way in!!

Please pardon the tone of the next question, but are you sure the prop is on tight using both prop nuts?

I hope you get the problem figured out soon..

alfredbmor

The engine should start fine when low speed NV is flush with the plastic cap of the throttle arm, as stated by hrrcflyer. Open the HSNV 3 or even 4 full turns and let the glow plug ignitor attached even after the engine starts. Run the engine as the manual indicates at no more than 4,000 for about 10 minutes (Glow plug ignitor still attached), then start to lean the engine to gain 1,500 more rpm (5,500) run this way for another 10 minutes and then lean again to gain some more revs. (like 7,000) and so on. Big Saitos take more time to break in, even after 5 or 6 tanks they are even in the process of the break in, do not desesperate, the reward is a great reliable running engine with a very nice low (About 1,900) and a good 8,700 rpm high.

There is a good informative review here:
http://www.rcgroups.com/forums/showthread.php?t=495580

Don41

Thanks hrrcflyer and alfredbmor

I do have the lock nut in place but it’s no match for a backfire. I’ll check that lv setting before venturing into town for lower nitro fuel.

Alfrdbmor,,, thanks for the site info. The manual has you start at a whopping 5 turns on high needle. I think I’ll try 3 turns for the next start attempt but make sure it’s blowing lots of fuel.

I’m definitely becoming a Saito junky in spite of the man killing 125 (:-).

Regards

scratchonly

They like a wet prime; with the glow off, open the throttle and flip it till you hear a sloshing sound, usually about 6 flips. Close to idle and give it a try. You might try a back flip with a chicken stick.

Don41

Ironically the way I am successfully starting at the moment is to disconnect the fuel line and glow off,,, spin it a few times with the starter then hook everything up and immediately apply the starter.

This works great on the test bench but a little impractical at the field.

I'm going to run a couple of more tanks thru her this way then setup as it will be in the plane.


BTW: Where did your needle setting end up? I know it's not still at the break-in 5 turns (:-)

Regards
Don

alfredbmor

[quote]ORIGINAL: Don41


Ironically the way I am successfully starting at the moment is to disconnect the fuel line and glow off,,, spin it a few times with the starter then hook everything up and immediately apply the starter.


The engine is getting flooded; try with the tank in a lower position.
Good luck.

Don41

[quote]ORIGINAL: alfredbmor


I made some changes in the fuel system and it seems to have done the trick. I also think that having about 30 minutes run time helps.

BTW hrrcflyer: I checked after reading your message and the low speed needle was all the way in. Perhaps this had something to do with the initial problems of backfiring.

At the moment the engine is starting with just a light bump of the starter so I guess the worst is over. However, after reading numerous comments from people that use cheat stiks I think I'll pick one up and give it a try. The last time I hand propped was in the early eighties (my 40 & 60 size 2 strokes). I don't remember any serious injuries from the activity but I certainly don't want to tempt fate again (:-).

Regards
Don

expo

My Feedback: (20)

I've got 2 Saito 1.00s that have never spun a prop nut off or backfired. I run them rich on the high end, with a good smoke trail and sometimes use 30% Wildcat when I use 16" props on them for some extra vertical.

hrrcflyer

Don41,

PLEASE don't try to hand flip a big four stroke. It will only have to bite you once and you will seriously regret it.[:@]. IMHO chicken sticks are OK for small four strokes, but the big ones have too much compression. I will never forget the time I was at the field with my Ultrastick 120 Lite which has a Saito 180 on it. I had forgotten to charge my flight box battery the night before so my starter would not turn the motor over past the compression stroke. Instead of borrowing a friends starter, I tried using my new chicken stick. Well, the motor backfired on the fourth flip and when it hit the chicken stick, it through it out of my hands, went up in the air probably 30-40 feet and landed at least 60 feet away. Trust me, I learned my lesson real quick when that happened..

I'm glad to hear your 125 is running better, now put it on a plane and go fly the pants off it

Don41

Chuckle. Thanks for the warning. My frayed nerves would be finished off if still another lethal object went flying around inside the shed.

I bought a Four Star 120 ARF specifically for this engine. It will eventually end up in my SpacewalkerII kit sometime next year (I'm not a fast builder).

Don