OS160 FX Problems
 

Have a 160 that has probably 4 hours of run time on the ground but no air time. Put it in my Dave Patrick Ultimate and went out to my flying field today to try it out. Plenty rich(I thought), held the plane verticle-no problems,took off perfect, flew perfect for about 2 minutes. Thankfully we had plenty of altitude, engine died with no warning at all. Landed and after about 3 minutes tried engine again, now have it so rich that power is questionable, took off flew great for 2 minutes then- DEAD STICK AGAIN. I have learned today how to ace the dead stick landing. Is this a problem that is common to this engine? OS 160 FX with B.C.M. pitts style muffler. I havent tried a pump. Thanks

RE: OS160 FX Problems
 

The most common problem is leaning the low end too much which leans the midrange.

What prop are you using?

Do a search on this engine and look for suggestions. This is one of the best engines I have ever run. No Pumps, no large fuel tubing. Runs great on 5-15% nitro and props from APC 17x8 to Mejzlik 20X6 once properly run in and adjusted.

RE: OS160 FX Problems
 

Flying with the engine running very rich will make it unreliable. Peak it with a tachometer and then open the main needle so you are 300-500 from peak.

RE: OS160 FX Problems
 

G'day Mate, I'm running an OS 160fx on 10% nitro 18% coolpower OS no.8 plug & APC 16x10 prop with a Bisson Pitts Muffler, runs perfect. what fuel & what prop are you running, 4 hours running is a hell of a lot, without flying it. Do like Flyer95 suggests as it should be well run in.

RE: OS160 FX Problems
 

The reason I had so much run time on the ground was several times when I was ready to take her out to fly, weather would not permit.
So I would end up with the shop door open and the plane anchored and just run the engine to give it time. Break in was as the manual
directed. Prop is a master airscrew 18x6, fuel is cool power 10%. I have been flying RC for 26 years and have always stuck with 2 Stroke engines-never did much with gassers.I love the way this OS 160 starts and runs initially, just don't understand why it dies.As for needle setting, I first tried highest RPM then opened needle until 400 RPM drop. That is where it was set when it died the first time.
I keep hearing that this engine needs a pump or that the muffler dosen't have enough back pressure. I wanted to get the opinion of you guys out in RC universe land before I started investing in pumps, etc. Thanks

RE: OS160 FX Problems
 

Well, you will get mixed reviews regarding pumps; the majority of which will be negative. This is the only glow engine, of the dozens I've owned, that I couldn't get "right". And it was because of plumbing problems, I'm convinced.

I installed this engine in a large Extra, and bought into the "wisdom" that one must have the fuel tank at the CG for a proper job, etc. Of course, that calls for some sort of pressurized fuel feed, as the engine can't draw from that far away.

Without going into a lot of boring detail, I first tried a Perry VP30, then a Cline regulator. The VP 30 was a total disaster. I worked with that thing for two MONTHS, trying every imaginable variation. The Cline was better, but the engine still seemed very skittish and, at times, unreliable on the mixture. So I got a gas engine for that plane and sold the 1.60.

I have no doubt that, if I had plumbed the engine normally and put the tank just behind the firewall, it would have run just fine. There are simply too many folks having great success with this engine to say it has a flaw.

It does have a lot more interaction between the needles than most glow engines. IOW, a change on either high or low speed needle will usually noticeably affect the other mixture.

So, I would imagine that you have a mixture problem; assuming the tank is in the proper location.

RE: OS160 FX Problems
 

Have you tried an OS-F glow plug? This plug works very good on some low rpm medium/big glow engines as super tigers and will take care of the excessive fuel much better than the colder plugs.
Run it slightly rich on both needles to prevent overheating.

RE: OS160 FX Problems
 

Hi Flyerdave,

If my last experience with OS160 FX mixture problems can help you :

2 months ago, I had differents fuel mixture problems with my OS 160 FX and I didn't understand what happened.
The problem was : all runs-up were OK on ground (in every aicraft position) but as soon my plane was in flight, after 2 minutes the engine had a flame out.
My configuration was : Aerobatic plane 78" and 12lb, propeller Mejzelik 18 x 6, muffler Slimline Pitts type, Fuel with 10% of Nitro and Synthetic oil, and the tank is not just behind the engine.
I have tried many solutions : Cline regulator, differents propellers, plugs, needle setting, fuels, and so, and so ...
Finally, after several tries, I have found "who" was responsible for my problems : The remote needle valve Assembly. If this one is too tightened, the o-ring inside is constraint and some outside air can trouble the air-fuel mixture. Same effect if the remote needle valve Assembly is not enough tightened.



And after all these attemps, for 2 weeks, my OS 160 FX run very well with :
- No more Cline Regulator (too much fuel pressure and needle too much sensitive)
- Glow Plug ENYA 4
- Propeller Mejzelik 18 x 6
- Fuel with 10% of Nitro and Synthetic oil

I apologize to you if my english is not perfect.

Thierry

RE: OS160 FX Problems
 

I had the same problem you are having, among others with the OS 160FX.
I finally found that the problem was the BCM pitts muffler, the exhaust pressure vent location was the problem. What would happen is the pressure line coming from the muffler would act like a "sink trap" and clog up with oil in the bottom of the loop, causing the pressure drop and the engine would gradualy quit if I throttled up. Got good at deadsticking a brick because of that.
I have seen this happen on about a dozen 160FX engines, but only when using the BCM with the pressure nipple on the bottom.

Change the pressure nipple location to the thick part where it comes directly out of the engine.

RE: OS160 FX Problems
 

Fuelman, that is a good call though I've never had it happen to me.

flyerdave,

One thing you can try is put only a few oz in the tank, start the engine and set the high speed needle to peak, set the low speed needle to as rich a setting as possible that will still allow a clean transition. You should be able to get a good extended 1800 rpm idle with this setting and only a slight delay in throttle response even after a five minute idle. After this, fill the tank and check the peak rpm and see how much of a difference there is between this and the previous peak rpm. I have seen it be close to 300 rpm.

This engine will run well with the OS #8 plug. I had the same one in it for about five cases of fuel until I installed a Jett Turbo muffler, then I went thru three in one day[:@]

One other thing to try is installing Hobbico exhaust extentions on the muffler. They seem to give just the right amount of back pressure on the smaller 160FX Bisson Muffler or install a BGX or ST4500 muffler with one exhaust capped and use one deflector. The larger muffler will allow larger props and cooler running.

If you add a few oz of castor or Klotz blend to your cool power fuel you won't have to worry about lean runs as much.

Please let us know how you make out.

RE: OS160 FX Problems
 

Skypilot,
It happened to me and Mike Pilkington from OMP, same exact thing. We were at the Dayton Ohio Giant Scale Show a couple years ago and started to trouble shoot it.
The only reason we caught it was we had the cowl off his plane and we were trying to figure it out on the ground by running it at lower throttle settings and midrange settings and we watched the exhaust pressure line fill up with oil and then eventually start acting like a sink trap. As the oil started not letting some pressure pass by, the engine began its erratic behavior and then quit. If the engine idled for extended periods it would not build up and if it ran at high throttle settings it would not build up, just at lower mid range settings where we fly quite a bit at.
We found Jim Bisson there at the show and talked to him. I don't know if he addressed it or not. We did have several other we encountered that have run into the same problem. Not very common, but it happens.

RE: OS160 FX Problems
 

Fuelman,

I wonder if by installing the deflectors/blocking off one stack I changed the back pressure enough to not have the problem? I use two fuel dots, with one tee in the line to the carb for filling and the other in the muffler pressure line. The pressure line has a tee at the low point of the loop, the extra oil may have been pooling in the line going to the dot.

Maybe I was just lucky.

RE: OS160 FX Problems
 

Sky,
Both Mike and I and everybody that I knew that had problems ran the BCM pitts with both holes open and nothing else, i.e. no diverters etc.
Which is probably where the problem came from, not enough back pressure to keep the sink trap cleaned out.
Mike changed the location of where the pressure tap was and problem solved. I put one of my Saito 180's on the same plane and continue to fly it that way today.

I did temporarly block off one of the exhaust stacks on the bcm pitts with aluminum tape and lost a considerable amount of rpm so I did not go any further with that thought.

RE: OS160 FX Problems
 

If I try relocating the pressure fitting, where should i put the new one? and how would you close off the existing fitting? Thanks

RE: OS160 FX Problems
 

I would re-use the pressure fitting in the new hole and plug the old one with the proper size screw, 6/32 or 8/32.

RE: OS160 FX Problems
 

I have seen this happen in large glow engines, for exactly the opposite reason.

I.e. not because it is lean, but because it is too rich.


When I adjusted my MVVS 1.60 (with tuned pipe), I adjusted the low end needle, so the mixture will provide a steady part-throttle and good launch transition, with the nose pointed straight-up.

With the large 22 oz, the level difference between the fuel and the tank is relatively large.

Setting the plane to a level attitude, after adjusting the low-end needle in a nose up attitude, caused the mixture to become so rich, the engine loads-up. And the sheer amount of fuel that rushes up to the cylinder, as the throttle is advanced, causes over-compression, which causes the engine to back-fire and stop, or even to throw the prop.

The only solution is a fuel pump/regulator, that will make fuel delivery uniform in all attitudes, so no richening-up will happen as the plane is set to a level flight attitude.

I know this happens with Moki 1.80 and 2.10 engines also.

RE: OS160 FX Problems
 

Dar,
That actually happened to my other 160FX. I pulled my hair out trying to figure it out since it would go rich in flight and do exactly that. The last time that engine flew, I idled back on an approach, then advanced the throttle a click or two and the engine backfired then started running backwards. The plane which was only about 20 feet in the air, immediatly stoped and fell like a homesick brick flat onto the ground. Damaged the plane pretty bad, took a month to fix.

On the same identical plane, about a month later, since I needed the nose weight anyway, I installed one of my Moki 180's on it (only differnece was the engine) and never had another problem.

I never did completly discover the problem with that one going rich and quitting in the air. Your diagnosis sounds pretty good and that could have been my problem. Although I only had a 16 oz tank and its location was pretty close to midline with the spraybar. I will never know for sure, since I have sold both 160 fx's and have not bought any since.

RE: OS160 FX Problems
 

Brian,


As I wrote, a fuel pump, which will make the mixture strength constant (and subsequent adlustment...) is the only way to go.

I use a Perry VP-30, but a Cline, or an Iron Bay are also good....
If only they cost less than 900% profit...

Without being sure the low-speed needle adjustment is PERFECT, don't take off!

RE: OS160 FX Problems
 

You guys sure do know your engines, I went to the shop, removed the cowl, looked at the fuel line going to the muffler, and guess what-about 1/2 inch of oil in the line at the bottom of the p-trap. Must have acted just like the water in a drain line stopping the back pressure to the fuel tank. I will be ordering a slimline muffler to replace the B.C.M. because I'm afraid if I try to relocate the fitting, I may not get the proper location for the best back pressure. Thanks

RE: OS160 FX Problems
 

Your English is excellent, no apologies are needed. And thank you for sharing your experiences. That's what this forum is all about, sharing and helping fellow flyers.

Cheers,

Chip

RE: OS160 FX Problems
 

I have (2) 160 FX's. One on a Pacific Aeromodel GeeBee (82") and the other on a GP Super Chipmunk. Both run very well with the BCM muffler, O.S. #8 plug, and 18X6 Pro Zinger prop. By the way, they are both side mounted.

RE: OS160 FX Problems
 

I have been running a 160 for several yrs with a Jtech muffler ,the pressure tap is on the top of the muff just past the exhaust port .I did find the bottom end on this engine is very critical and took a while to get it set correctly .I wont use any pressure tap that is on the bottom of the muff because of what has been said here ,at lower RPM's it fills with oil and decreases the tank pressure .I started out with a No. 8 os plug and changed to a A-3 which helped a ton for mid range ,but I have gone to a f -plug now they run great and last longer than the A-3.
So far I haven't had to go to a pump and as long as the engines runs the way it does I won't.
Also make sure theres a gasket in between the muffler and the engine a leak here will cause a drastic loss of tank pressure .Hope this helps Happy Landings

RE: OS160 FX Problems
 

I use ultra copper silicone for the gasket. Apply a thin layer on one side, assemble and lightly snug it up, the next day torque it down.