I had problems with OS's FP line back in the 80's but the SF line was top notch, same today. MY OS 61 FX has been a sweet heart of an engine

I have four .46 O.S. LA's on my C-130, which was first flown in 2006.

This aircraft is typically flown once a year at my home club's annual Flying Circus event; the rest of the year the wing hangs on the wall collecting dust.

When 'show time' comes around, I service the fuel tanks, connect the external glow and the moment the fuel reaches the carbs, the engines fire; I have never experienced a flame-out or any problems with these engines.

http://www.youtube.com/watch?v=fwNr9Zik25I

http://www.youtube.com/watch?v=f46Pn...eature=related

I also have an O.S. 1.60 2-stroke in my DP Supercub and have never had any problems with it; this is a very easy-starting strong engine primarily setup for aero-towing and aerobatics.

My experience with O.S. 2-stroke engines has been very good so far.

Joe

Although any engine/manufacturer can have good engines and bad engines, my experience with OS engines over the years has been exceptional. I still have and fly OS engines that are over 25 years old.

The latest engine I picked up from OS is the .37 SZ-H and it has run flawless from the first moment I started the engine over three years ago. I have not had the same luck with other engines (TT).

The LA series engines by OS are just that, cheap engines meant for the entry level pilot. I have an old .46 LA and it ran okay but was nothing spectacular, I knew that when I bought it. Bottom line, you pay’s your money and you get what you pay for. I’ll always use OS engines as my go to engine period.

Steve

i think OS makes better 4 cycle motors, than 2 strokes. except for maybe the ax line.......RON

... back to the first post... never use thread locker on anything nylon or plastic.

hi
flying OS two cycle glo engines for 20 years about when the FS series of engines came outthe FS series and the FSR series ( earlier than the FS series ) of engines have always performed outstanding for me( powerful - reliable cannot wear them out ) as did the earlier FP series (aluminum color )
had problems running my 91 FX engine until OS made replacement parts to remove the needle valve from the back plate -as heat transfer was causing air bubbles in the fuel line from the remote needle valve assembly to the carb took me to long to correct the problembut my engine was not damaged as some required new bearings and ring from OS due to air in fuel lines causing high heat problems and metal damage
i have a 75 AX that is a powerhouse and turns an inch more prop than my 91 FXthe power the AX series and size props they turn for there size engine just surprises me all the time they are the most powerful OS engines ever made IMOmore money but worth it
i love my OS 46 FX my Evolution 46 glo my evolution 52 heli engine and my ST 51all the above are super strong runners for 40 size airframes
i am very sure that my outstanding success with all my two cycle glo engines (only style engine i chose to fly ) is totally due to the glo fuel i usewhich is MORGAN OMEGAcastor and syn mix15%- for 18 of my 20 years in the hobby (do see my quote at the bottom of my post )
the first two years i flew i used MORGAN COOL ( crule ) POWERand i suffered all kinds of engine wearrings -bearings etci do all my own engine repair work-i would never use a full syn fuel for any reason after that experience ( just clean the plane off )
i truly cannot remember the last time i needed to replace a set of bearingsi do change a ring from time to time if compression falls offa new ring brings the compression back as if the engine was new again
my engines run and stay newbreak in procedure has a bit to do with my results
that is my own experience with OSand it is generally great
BEST REGARDS TONY

All I have are SFs. These are so well built I havn't had to get a new engine to replace them.

So, back to the OP. Seems it was you. Loosening mount bolts means either no maintenance (checking the bolts, especially after the first few runs) or poor installation. The plastic backplates do loosen due to thermal cycling, but again, it comes down to maintenance, nothing to do with the engine/quality. The other engine killer is expecting too much from it, especially simple plain bearing engines like the LA's. Screwing the neck of it with too big a load and needle tweaking will destroy them pretty quickly. Look after them and they, and all engines, will last well beyond what would be considered 'normal'. For another instance, the LA 46 in one of my aerbatic models has just had a liner/piston change, but first flew in 1998...just another example of poor quality OS liner plating? I have no idea how many hours of operation that represents, but given the size of the engine, and the number of miles that piston has travelled up and down that cylinder, I ain't complaining...
Evan, WB #12.

well i took the 46la out of my plane because its shaking my plane to peices. i understand the back plate since its plastic it will expand and stuff while the motor heats up. so i put on my test mount that is mounted to my deck and ran a few more tanks threw it and it is getting worse after changing props and balanceing them right before use. from what it seems that is the crank shaft is out of balance bad. its starting to kill the front bushing. its not running to lean so don't even waste my time saying that and its tuned right. ive never had any motor acted this bad i normaly have bearing motors. ive had a few bushing motors to and they still work great i think i just maybe got a junk motor but still from what ive seen from other people that bought new os motors the quality and QC just dropped off alot from the last few years.

What kind of problems have you had with your Magnums? Details, please.


Ed Cregger

I just know that they don't last as long like O.S. does. Only good for a handful of years before they need rebuilding and new bearings.


Pete

armyguy, that does not sound anything like 'normal'. I suggest that the motor be stripped and inspected, cause something is wildly wrong. I have 6 LA's (15 to 46) and none of them have ever exhibited the symptoms you describe. And being as bad as you describe, whatever it is must be very obvious when you find it. Knowing the usual production process you will have exactly the same bits in yours as I have in mine, and I can't fault the ones I have...
Evan, WB #12.

Even the worst engines will fire on the first flip or two. You just need to know their particular requirements. Now running consistanly at the same speed is another matter.

I don't think the screws are plastic, only the backplate. I could be wrong. No telling what OS will do next to compete with the Cinese.

So, what experience do you have with Magnum engines? Specifics, please.

All my OS's have been great .25AX, .25FP, .46AX, .55AX, .75AX, 40FS, 110FS. All except the .95AX for some reason its a lemon, other members at my club have also stopped using them. They seem to overheat even with adequate airflow over the head, i always thought i was getting fuel foaming, but the latest fuels have anti-foaming stuff in them.

What I have found with the newer OS engines, particularley the AX range is the metal alloy they are made of is very lightweight but not strong.
Icrashed my Showtime 50, with an OS 55ax in it, from aprox 6 feet above the ground, flying medium to slow speed and the engine just shattered when it hit the tarmac.
I have never in 35 years of crashing models seen an engine so destroyed. It was like it had been dipped in liquid nitrogen and hit with a hammer.
The only reusable parts were the front bearing and the 'glow plug.
All my older engines no matter what make survive being crashed remarkably well.
Only my YS110 have I had to replace a cranshaft on, but that was after 6 years of running, very high hours, and it had hit the deck a couple of times over the years.

The OS fourstrokes as well, if mounted inverted and you do a wheels up landing, the rocker cover and rockers just shear off, whereas before the rocker cover would scrape or just crack.

Isuppose the moral of the story is , donnt crash, but where is the fun in that?
The price of progress.

Darryl

What is really at hand in the OP's question is the fact that not enough oil was used in a bushed engine. LA's and their older siblings FP's are bushed, they need castor. Castor is king with ringed and bushed engines, yet there are a lot of people that cannot understand it or are just ignorant of it's need.
LA's should run on 22 to 24% oil total by volume, half castor, half synthetic. My son has an LA40 that was given to him, he flies the heck out of it, I just dumped 4 oz of castor in a gallon for it.
No problems, stock plastic backplate with remote needle.
Chris...

well after further look into it. it was not the lack of oil i had penty going threw it. the problem came down to a bad crankshaft that was way out of balance which caused the front bushing to get out of round and wear very fast so the motor was eating itself from the inside.

Crankshafts are deliberately made 'out of balance' so that when it is connected to the rod and piston the reciprocating balance is zero. Crankshafts, of their own, don't get unbalanced. If the front bush wore, then it is more likely down to something coming in with the air through the carb causing abrasive wear, a bent crankshaft from a previous crash, wrong oil, or not the right amount, use of an 'electric finger' damaging the thrust washer and causing bits of fine metal filings to get between the bush and crank or a badly balanced prop, although you discount the last possibility. There isn't really anything else...
Evan, WB #12.

Off topic.



Pete