saito 91 driving me nuts

[scooby61]

help me some body before i throw this motor off into the woods. i'm running a saito 91 in a funtana x50 ( it cost me my s40 airframe already) keeps dead sticking on me about 3-5 min into flight. it has about 2 gallons of 30% through it. ive rebuilt the carb, checked valve lash, replaced the plug, and retuned from factory settings several times. last flight i got it tuned well enough to run but some one at the flight line decided to take off into my landing approach forcing me to abort and i ran out of fuel too low to get a good glidepath and did some minor damage. so here's the problem, if i lean it out to get best power it won't idle low enough and will quit midflight, if i richen everything up enough to run in flight i still have to blip the throttle at low stick to keep her running. and at that setting i only get about a 5 min flight with more fuel on my plane than getting burned in the motor. any ideas

[heligrom]

well, i'd say start out from factory settings on both the needles. on the BENCH, tune the engine to turn the prop (by the way, which size are you using???) around 10,000 RPM then richen it about 1/8 turn. also, you have to adjust your low speed needle properly to get her to idle right. if shes too rich, she'll load up and die. too lean and she'll cut out when you transition quickly to mid or high throttle

also, a quick side note about your fuel running out in flight when you had the good flight. leave yourself plenty of extra time to land. if i can take a 14 minute total flight, i set the timer on my radio for 9 mins and 30 secs so i have a good 4 minutes to land in case something happens. you dont want to be landing when shes almost out of gas.

[scooby61]

planes at a freinds house i think i have a 14/7 or 14/6 on it, dont see how taching on the bench is diff from onthe ground on the airframe though. and over a year ago when i got the motor i was getting 8-10 min a tank then all of a sudden this starts happening its hard to set a timer when it varies so much from flight to flight and seems to need constant adjustment.

[flashburn]

Replace the bearings yours are rusty. If that does not work pm me and I will buy it if we can agree on a price.

[scooby61]

really think its the bearings? i don't notice any unusual vibes and its been after run oiled regularly. but ido have to retighten the muffler pipe every few flights.

[66stang]

Does it have a cowl on it. Could it be getting hot? Also drop down to 20% and see if it does better. Is fuel old?

[flashburn]

They are really prone to rusting and high nitro fuel adds to the problem. The little bit of added drag even lightly pitted bearings have will give you fits.
You can send it gack to Horizon and let them look @ it. I have sent a new Saito back with the connecting rod siezed onto the crankpin. They stripped the engine and found galling/debris on the crankpin. The engine was repaired and the bearings replaced. It only had 10 flights and they said the bearings were pitted. They will return it test ran with a new glow plug soaked in oil and sealed in a plastic bag. My repair was under warranty but the invoice did show costs and they were very low. Horizon even payed the return postage back into Canada.

[Unbalanced]

It sounds like you're trying to fly without completely tuning the engine. Take a look at this thread on another site. It should help you with understanding your engine.

http://www.rcuniverse.com/forum/m_5843055/tm.htm

[scooby61]

all replies duly noted, no my fuel isn't bad at least my heli's don't think so. i've temped it many times not running hot. bearing issue is a possibility i will pull the motor down and check them. i've had several guy's who fly a lot of saitos tune on this thing and same results everytime. so i must do something or lose another airframe to it.

[Unbalanced]

Run a whole tank on the ground. Run it at all throttle positions. Idle for a min or two and throttle up. Once you can get through a whole tank on the ground - regardless of what you do to make it better - then fly it. It's always better to figure these things out on the ground than to fight deadsticks.

[customjrod]

	Quote: Originally Posted by scooby61
	all replies duly noted, no my fuel isn't bad at least my heli's don't think so. i've temped it many times not running hot. bearing issue is a possibility i will pull the motor down and check them. i've had several guy's who fly a lot of saitos tune on this thing and same results everytime. so i must do something or lose another airframe to it.

The engines junk bro, Ill give you 100 bones for it.

[statbeast]

It seems to me like you may have adjusted the high speed needle to much to compensate for the idle (which should be done with the low). I like the previous suggestion of going back to facotry settings on both needles and slightly richening the needle. My Saito .91 runs like a top and has for years. All Saitos are excellent engines when adjusted correctly. I have used Horizon's service on a few of my Saitos and they are very fast and very reasonable so if you can't get it running by using facotry needle settings, let them have a go at it.

[scooby61]

motor runs but even when i run a whole tank on the ground it runs diff. in the air. i will dissassemble the carb and clean, reset to factory, check the bearings, and retune from there again. as for the 100 bones i 'll let the whole plane go ready to fly for 500 brand new airframe good servos well built i built up the landing gear section right out of the box as funtanas are known weak in this area. but thats a post for the swap shop and i like the way the plane flys when its running not ready to give up on it yet.

[Spaz]

replace the tank and fuel lines.. all of them, and check or replace the seal at the jug/carb tube.
Also have you adjusted the low end? factory set is realy realy realy rich
os-F plug is one of the best too
and Very important with any 4stroke is to make sure it's warmed up before adjusting the high speed (or you will chase settings all day), and do it with a tach, you can not hear the rpm's change as good as a 2 stroke.
good luck

[heligrom]

i agree with what everyone else is saying. reset everything back to factory and work from there, adjusting by small increments at a time.

also, saitos should run well forever. there are guys at my field that have saitos that are YEARS old and run amazing. again, take it slow. relax it takes a little time and although you may not fly this weekend, you'll have a well tuned engine for next weekend!