sgarrgo

i have two os 160 two strokes . i have one for over six years runs like a swiss watch. bone stock 20% fuel , med,fuel lines, idle bar fox long plug. you couldn't find a better engine.
just got another one. I have been at it 20 plus years and i thought good with motors. but this one stumped the band. i have changed everything i know and have asked all the locals.so here we go.
you can set the motor on the deck runs great. I flight it goes lean. so put large fuel lines, tank height , tank, vibrations, in tank or lines. checked motor for leaks case, back cover, carb, even shortened head bolts to make sure they were not bottoming out. fuel, plugs all kinds. used 18x6 prop. on last one so did the same on this.
checked baffel in muffler for same location as my last engine.
i put large fuel lines from tank to carb. also vent line to tank. now it will fly at full thro, no problem, i have problems with motor stalling on aproach. do touch and goes
just as you line up on runway props stopped . re-ajust idle ,and low end no change, still stalls.
i had another freind in my area have same problem with his new os 160. we couldn't resolve his either.
my old one ran so good it was a no brainer to get another one. now i don't think so.
any help would be nice.

allans

My Feedback: (11)

How big is the Tank? I suspect 500 to 600 cc's ?

David Bathe

Have you tried a larger prop? 18x6???... we use 18x10's, 17x12-13's on the 1.40RX in pattern The 1.60 is also very popular and swings props in the same area.
18x6 appears far to small from where I'm standing, will rev to high.

Other stock must does with that engine is say 10% and one extra head shim and an F plug.
Try some nitro, the F and a larger prop. Revs.. say low-mid 8's.

Flyboy Dave

My Feedback: (21)

[sm=regular_smile.gif]....Welcome to R/C Universe, sgarrgo....[sm=thumbup.gif]

I experienced the same problem with an OS .61 long stroke engine. It started
and ran perfectly....ran real good....but on landing the engine would quit coming
in, after I chopped the throttle....after about 15 to 20 seconds of chopped
throttle. I adjusted the carb every which way....the problem persisted.

Finally one day I decided to change the plug, even thought the engine started
and ran good. I had purchased the engine from e-Bay. The engine had an idlebar
plug in it. I tossed it as far as I could.

End of problem. Get rid of the idlebar plug. Try a Fox Miracle plug. [sm=wink_smile.gif]

FBD. [sm=teeth_smile.gif]

sgarrgo

thanks for all your ideas . fuel tank is 20oz, fox idle bar several new. i have tried os 8 os 4 ect. fuel is 2020 byron. used for years. the old engine ran on 5% to 20&
i tried 30% but, it wanted to heat up. thanks for your help. we fly at about 3600 ft altitude and higher most season.
my first engine is aprox 7 to 8 years old. in last few years has os changed. compression or carbs? i hate to take my old one apart to check, if it isn't broke don't fix it.
Is there a good link or e-mail to os tech support? i have lots of them and had great luck.
i have not sent it in because bench run doesn't seem to show any bad habits! but it almost cost me a Q yak.
larger props good question. 18x6 turns 9100 rpms. i have run 18x8 it acted like it was loading up a lot on vertical.
thanks dave , david and allan for ideas to help.

Checklst

How is the tank location........high ...low or center line of carb? Had a high tank location flood the carb on landing approch once.

mugenkidd

My Feedback: (94)

you still have both of the screws in place that hold the carburator on to the crankcase ? Sometimes those will come off and give you crazy behavior.

sgarrgo

up date on 160
carb srews in with blue locktight,
tank center is middle of needle.
going out sunday run so more. i just won't get where i can't dead stick in. maybe more break in time. change fuel , plug , motor mount. larger prop 18x8 maybe
to many rpms. all engines are not created equal.
thanks

Flyboy Dave

My Feedback: (21)

....I think the prop recommendations by OS for the 1.60 are absolutely
ridiculous.....way, way too much prop. If it's not turning 10K, it's over
propped in my opinion. This may not apply to your case....but sometimes
if an engine is overheated, it will die when you chop the throttle.

If you are going by the hobby shop, pick up a Fox Miracle plug, they can
help with a troublesome engine.

FBD. [sm=teeth_smile.gif]

David Bathe

Nothing wrong with a bit of old school thinking but haven't the engine manufacturers, serious competitors (and even the Sunday hobby flier) have had to adapt to a different, quiet way of thinking?
The hobby is demanding high power from a very quiet packed, that's led to the engine producers to start designing motors that deliver the beef at low, thus quieter RPMs
Max torque is the area to aim for. And that's normally miles away from the point of max rpm.

For me 18x6 is way to little prop for that engine. Having said that I have no experience at operating at 3600ft (or higher) above sea level. For me that's similar to flying on Mars!
I know it must have some considerable effect of model engine operation. Exactly what, I haven't the slightest idea.
I'd first try some decent 10/15% fuel. Synth oil 18% would be plenty and a OS F type 4 stroke plug. If that isn't available an Enya No.3.
At least after that, you can eliminate the plug and the fuel from the potential problem equation.

sgarrgo

WELL I WENT TO THE AIR GODS AGAIN LAST WEEKEND. I CHANGED LOW END TO BE LEANER, PUT IN A NEW PLUG, I CHECKED THE LAST ONE TO SEE IF IT GLOWED ALL THE UP AND IT WAS A LITTLE SHORT OF A FULL GLOW. CHECKED LINES, TANK HEIGHT, RESET HIGH END NEEDLE.
TOOK PLANE UP. IT RAN GREAT ON NORMAL FIGHT. I STARTED DOING TOUCH AND GOES ALL WAS FINE. I STARTED DOING SIDE SLIPS WITH THE NOSE DOWN A LITTLE AND THERE IT WAS DEAD STICK AGAIN. SO RESET TRIM JUST A LITTLE HIGHER, JUST IN CASE IT WAS TO LOW. SAME RESULTS DEAD STICK. THE MOTOR RUNS SUPER GOOD SMOKE FROM EXAUST, GREAT TRANSION. IF YOU KEEP RPMS UP ON APROACH, LIKE TWO OR THREE CLICKS IT SEEMS OK. BUT CHOP THE THROTTLE DROP IT IN PUFF NO MOTOR RUNNING. ITS GOT TO BE IN TANK I THINK ? G-FORCE, CLUNK ECT. MAYBE FLOATING????
BACK TO THE HANGER, SCRATCH MY HEAD AND BE PATIENT, ITS GOT TO BE SOMETHING SIMPLE. OR MAYBE I AM FOR TRYING TO FIX IT.
I AM NOT SURE WHAT RPMS OS SAYS IT SUPOSE TO RUN. I HAVE 9200 ON DECK AT 3600FT ABOVE SEA LEVEL WITH 18X6 XOAR.
THANKS FOR THE IDEAS ITS NOT FOR SALE YET?
STEVE

David Bathe

I think you have to try an OS F plug and some nitro, 15% would be perfect Steve.
Try the plug though, it's like nothing else available bubba. And by the way, I did some checking around, non of the 1.60's in my neck of the woods are using large bore fuel tubing, just plain old regular.

nedyob

My Feedback: (67)

I went to a OS F plug and a bigger tank. Mine was leaning out in mid flight about 1/2 through the tank. I haven't done this yet but I've heard that some people went to a Perry Pump when OS moved the needle to the rear of the engine. I've read threads where the pump solved there problems and there engines ran great no matter what prop, fuel, plug used.
NEDYOB

David Bathe

OK, here's another thing that comes to mind now that nedyob bring it up. Everyone I know uses a Perry and a pipe, thats because we're flying pattern.
Now, if you're using say a Bisson pitts muffler for example I know that it just doesn't make enough pressure by far as is. You need to completely block off one of the exhaust pipes so it's running on only one!
Maybe your problem is simple not enough tank pressure when you're at idle on a half empty tank? I've done this mod' to my Bissons years back.
What ever, Use an F plug.