I have a new OS 160 with ~ 1 gallon of fuel thru it, which is having a fuel delivery problem, the motor cuts out when angled sharply upward. We have replaced and or inspected all fueling hardware, etc. , except for the carb oring. I am using a Pitts muffler, and was told I needed some back pressure, so I have nearly blocked one of the pipes, but still have the problem. I am tired of dead stick landings, any idea? ben

Well, for starters, which OS 160 are you referring to? Are you having a problem with the 160 two stroke single, or is it the FT 160 twin cylinder 4 stroke?

Bill, AMA 4720
WACO Brotherhood #1

Bill, its a two-stroke, ben

Bill,

I haven't witnessed Ben's problem, but it was described to me just as he stated. The problem arose just as the motor has begun to break in.

Bens 160 fx is in a Giant Ucan do -side mounted with a Bisson pitts muffler and 1 exhaust plugged off
we reproduced the problem in my shop -simply by running it after we had pulled all the lines -cleaning the remote needle- checking for holes -airleaks , pulled the tank apart, etc . we started the motor held the fuse then started to slowly tip it slightly up, all was good till about 45 degrees and it suddenly stopped just like inflight conditions. This motor runs excellent on the ground and in level flight. good transition, nice power at top end, reliable idle, 18/6 zinger, he is running 15% fuel 18% oil Byron I believe, A warm Glo plug
Ben experiances this problem on split S entry or attempting stall turns with a dead motor each time.
the tank location is in the stock location We find no foaming or air bubbles
It is a head scratcher for sure. Seems like everybody who uses a pump just takes them off later so that really isnt a cure. There are literaly hundreds of these out there with the same setup, and i have not heard of a problem like this, We are at about 1000 ft altitude at our field

The carb does not seem to be loose in the barrel but there seems to be weak fuel draw on the upline I have wrinkled my thinking cap on this one. anybody else got any input as to cause ?
Don Olsen
Evening Air Hobbies

I fitted a Perry carburetor on my 160FX and I have impressive power, swinging a 18X6 masterairscrew @ 9400 rpm on rich side of the screw.

I made many experimentation. I have run this engine with OS muffler, and with Pitts Muffler and Cline Regulator, all with no good results. Lean running in middle range , overheating and dead stick power.

Now, with Perry Carburetor, Pitts Muffler and Cline regulator, the 160 run very strong and lean dead stick conditions are completely end.

Very strong impressive engine.

Sorry for my English.

Did you say a remote needle valve? Is there a needle valve that came with the engine that is attached to the carb in the normal fashion? I have seen some really strange problems that crop up when using the remote needle valves that so many have become infatuated with. If you have the traditional needle valve assembly, try using it and see if your problem persists. Also, does it seem to matter how much fuel is in the tank when this occurrs? If you have a tube extension in the tank for the vent line, you may be blocking the vent action with fuel, causing the carb to stop drawing fuel (pulling a vacuum in the tank). Try this with only 1/3 tank of fuel and see if the same problem is there. It may be just a plumbing problem.

Bill, AMA 4720
WACO Brotherhood #1

Thanks Bill
we eliminated all the plumbing probs and this motor only comes with a remote needle we did a test with a 1/2 tank same thing the tank is the one that come with the plane, the clunk is free the vent tube is not touching or blocked we did replace the fuel line that goes from the needle to carb because we felt it was too loose maybe drawing air with vibration no joy
Don

Are you using the pressure tap in the muffler? You may need to use exhaust pressure to keep the carb supplied. That, or an air leak is about all that would make the engine do what yours is doing. I know that this may be simple, but are you using the larger size fuel line?

Bill, AMA 4720
WACO Brotherhood #1

Thanks Bill
been there done that. Like Ben said we eliminated everything but the carb. the screws holding it on are VERY tight and it was getting late so we didnt take it off. it chokes well so I dont believe the O ring is our culprit. Yes I agree that it seems very much like an air leak somewhere
Don

Hi!
Try running the engine with the original OS silencer. 5% nitro, 18x6 Menz wood prop (no MA Please) and OS 8 or Enya 3 glowplug...thats all it needs

Regards!
Jan K

Hi

The real trouble on the FX160 is his 60F carburetor. This carburetor is originally designed to FX91. I think Os as fitted a FX91 carburetor on a FI160 (fuel injection 160) to civilizing the price.

I have a FX91 and FX160. On the 91, the 60F operate just on the limit of possible in middle range (a little bit lean) wen Hi and low range correctly adjusted. On the 160, It's impossible to adjust the hi range in Rich condition (3 turns and more on the needle valve) and if you run your engine in middle, your engine will operate w/o smoke and will stop on overheat and grip its piston in the liner.

The ultimate solution, for me, is the PERRY carburetor.

JJ Marier

HI

I've seen this problem 3 times with the OS 160. The cure for 2 of them was to tighten the swivel fitting on the remote needle valve.
Number 3 has been tighten but not tested. They ran good on the ground but went lean on a vertical.
Good luck
Ken

Gday,
Which Perry carby are you referring to?

Regards
Mark

The carburetor is not likely the problem. The OP has stated that the engine runs well unless it's nosed up.

Has the clunk been drilled-out so that it has a larger I.D.? How about the fuel tubing? Larger engines need larger tubing. With their higher fuel consumption, you can get drag from the narrow tubing that impedes fuel flow. Many times, you get just enough fuel flow in the level-flight codition, but when you add the chore of having to move the fuel 'uphill' (when in a climb) the fuel-line drag slows the fuel even more, and the engine leans and dies.

This was first noticed when the BGX-1 first came out...people used regular fuel line and found the same problem. In level flight, you can get just enough fuel flow, but go nose-up and the fuel flow slows enough to cause your problem.

Many times, you have to re-plumb the fuel system with the next size larger tubing. We use Sullivan tanks on all large engines, and use the next size of brass tubing, larger silicon line, drill out the clunk, and wire-tie everything in place so it won't slip off. That's cured many, many fuel-delivery problems.

Again, it's not the carb.

bax, where and what size larger fuel tubing, do you need for the BGX-1 3500?
ALSO can you get a larger fuel nipple?


thanks

I'm a fan to OS products but, I'm sorry Bax, the carburetor is the problem. The 160FX is not easy to tame.

I have run this engine on a bench with the os muffler and large tubing. I never can run in rich condition at full throtle (3 turn on needle scew) and with idle screw correctly adjust to good idle and good replay, the engine has running very very lean in mid throtle (4500RPM) and grip the piston in the liner. I have tested with a Cline regulator (between needle and carb and before the needle), same thing, impossible to adjust correctely.

I had a perry Carb (0.375 venturi) in my shop and install on it. Now the engine run verry smoot with strength power and all the time in perfect air/fuel ratio. The engine is install with cline regulator and pitts muffler in a Yak 54 72" and swing a Masterairscrew 18X6 at 9200 rpm (9400 peak). The power of this engine is verry impressive. It's a beast.

The perry carb is # 4501, (0,375 ventury 0,590 buddy) http://www.perrypumps.com/prod01.htm

Sorry for my poor English

JJ Marier

We use the brass tubing that has an I.D. that's the same as the O.D. of the tubing supplied with the tank. We drill the clunk so that it has a constant I.D. The I.D. of the fuel end is smaller than the I.D. of the end where you attach the fuel tubing.

Hmmm.....if the engine cannot be richened with a very wide-open needle valve on a test stand, then we'd most certainly say that there's some kind of problem in fuel delivery to the carburetor. We've run a very large number of O.S. Max 1.60 FX engines over the years, and have never seen the problem you mention, unless there's a blockage in the fuel system, some kind of air leak, or other fault in the fuel system.

Of course, since we can't actually see your engine and run it, we'd not know where a problem may be.

Ben; I've the same problem with a GMS 1.20 and solved it by changing the propeller. I found that it's a thrmodynamic problem... but to summarize: you're not absobing enough torque so the engine gets really hot. Once this hot temperature is reached fresh fuel into the crank looses its properties and combustions cannot continue.
Try a bigger propeller; you've nothisng to loose with this test...
Good Luck
Guille

If any one is interested, Ben changed the fuel line from the remote needle to the carb. That fixed his problem.