hello everyone.

I just bought an engine from someone on this site and was wondering. the engine is an os max 46 sf. now, i cant seem to find any info on this engine. is this a discontinued model, what is the difference between that and an la, or ax? also, will it be ok in a spitfire 50? i need to know. its a little late to retract my offer, i know that, but i need to know if i have to get another engine. guess i should have researched this a little more before i purchased it. thanks in advance for any info/advice anyone can give.

The SF series was made during the 80's and until the early 90's...it's a good engine, and if yours is in good condition it will fly your Spitfire well. It's a lot more powerful than an LA series but not quite as powerful as the new AX series.

great. this thing looks like its new, and the guy said it wasnt used much. i hope its a good engine, though, now knowing its age, i may have paid a little too much for it. but its ok. im still learning. thanks for the info!

I have three of them and have been running them for 20+ years. They are a great engine and as good as my AX's.

Bruce

I have two .25 SF engines and they are great! There is nothing wrong with older engines if they were taken care of. The SF designation indicates it was the sport engine with bearings. The bushinged engines of the time were designated FP.

They are good engines. If you should need parts just find the correct version on this list of discontinued OS engines. http://www.osengines.com/parts/discontinued.html Yours may or may not have a ring for instance. This will change which part list you use.

thanks for the info guys! think im going to have fun with this. itll be a good, inexpensive engine to start with. (probably more than i should have paid, but much less than the new one i was looking at). i found a parts list, and instructions for setup. now all i have to do is figure out how to mount it in the plane. next thing i have to pick up are all the servos. any good suggestions? im trying to get some jr ds821's cheap.  was hoping to go digital. thanks again!!

My OS 46 SF is one of the best running engines Iown and Ihave quite a few. Value is relative, you may not have gotten any better engine for your money than you did.

i have one more question about this engine. once i get it, im reading about bearings being rusted and such. now, i know my way around a car engine, do the same principles apply to this engine? if so, i know what im looking at and can tell if something is bad. i want to make sure this engine is good. if not, im just going to rebuild it. thanks for any info anyone can give.

It's pretty easy to check...pull the backplate off and look for rust...turn it over and listen/feel for roughness in the bearings.

If you need to change them, there are numerous tips in the Glow Engines forum...and there's a good a tutorial on changing bearings on youtube.

It's pretty straight-forward, changing bearings, and if you've got mech. experience like you've mentioned, it's a piece of cake to change 'em.

There is a how to on bearing changing on this site,
http://www.masportaviator.com/
bearing are likely the same for any OS 40 or 46.
All the how to stuff here is a must read for a new flyer IMHO. Save it to your favorites for a reference.
The SF series is a winner. I bought one for a buddy on Eba^ NIB reasonable. He has flown it for three years so far.
This is the parts list. OS has discontinued it but there are still parts out there new. Eba^
http://www.osengines.com/parts/xr15420.html

thanks guys. ive retired from the automotive business, thanks to gm closing all the dealerships that they did. but i have more in tools than i care to mention, and lots of experience. so this should be a cake walk. i just want to make sure its good  before i take the time to mount it.

Get you some Rislone and use it for after run oil. Put some in your engine, slosh it around, and let it sit a day or two. If brown stuff comes out, that is dissolved castor oil crud and not rust. Castor crud is a good thing in moderate amounts.

if i remember correctly i used to own a 35 sf, it was in a flair piper cub that was given to me. the engine back then was 20 years old and never missed a beat. i got rid of the plane and engine just over 4 years ago and i bet that engine still runs now. the previouse owner would put a few drops of oil in the engine before storing in a dry place over winter and he repeated this since he bought it new then i did the same when i had it.

PS the flair cub has a 72 inch wingpsan and this model was 6lb and coverd in solartex then painted in cellulose, very heavy for its size but the engine pulled it great with bags of power