FLYBOY

My Feedback: (11)

I have to say that I have been a die hard opponent to anything OS since they put the needle valve in the back. I have tried about 6 different OS engines with the needle back there and have hated every one. OS ate 2 91 FX engines that were bad, the 48 FX was OK, but not great and a couple other 91 FX engines I just pitched in the garbage.

I just ran the 55 AX that I bought a couple years ago. I haven't run it because I didn't want to be dissapointed, but I decieded to fly today with a new plane I put the AX in and I have to tell you, OS got it right again.

I used to be a die hard OS only guy for a long time. Man, this is the OS I remember. First run out of the box, I ran it for about 30 seconds, put the plane down and flew it. It was like it had been running for a long time. It ran flawless. I only got 2 flights in but both were amazing.

So far all I can say is WOW, great engine. Just like the old 61 SF engines used to run. Right out of the box they were awesome!

Can't wait to fly it again. I am glad they pulled their heads out and made a good product again. I have flown many brands of engines but swore off OS after the FX blunder. I hope they make a 91 AX like this if they don't already. The FX wasn't worth the scrap, but the AX seems awesome so far.

MinnFlyer

My Feedback: (4)

Hey Ed, if you like that 55AX, wait till you try the 75AX

FLYBOY

My Feedback: (11)

I am just looking to see if they make a 91 AX. That would rock, if not I will try the 75 in my Gee bee. I am throwing the FX 91 away that is in it. I have a friend that wants it bad. He says he likes them. This one runs like all the others I have had.

On my way to tower now to see what they have. Sweet engines those AXs. [8D]

MinnFlyer

My Feedback: (4)

I wonder if the 75AX carb would fit on your 91

Robotech

My Feedback: (9)

This is a prime example of one bad apple spoiling the whole bunch. I've had many OS engines over the years and all were excellent except ....... the 91FX. What a piece of junk. Luckily I didn't judge the whole line by that one model though and got the 61FX and several 46FXs.

daveopam

My Feedback: (9)

I bought the first OS I have owned in 15 years. It is the new 1.20AX. Like you said it required almost no break in and runs like a top.
VERY VERY happy with it.

David

macdona

My Feedback: (3)

I must have got the good one. My 91fx runs great.

fireman7875

My Feedback: (7)

It seems weird to hear complaints about an OS engine. I have had many and never had one that ran less than perfectly.

Brian

Kemosobie

All of my run great

scottrc

I have not been to crazy about the odd styles and dimensions of the new OS engines, they have been a pain to fit into my old planes, especially the Ultra Sport.

I have been collecting the SF engines and am glad I did, at the past couple of swap meets I have been two, these older OS engines have been in high demand.

I would agree that 55AX is a great engine, but I did have problems with mine with the Slim Line muffer.

noterman

OS may have redeemed themselves with the smaller 'AX' engines, but the 120 AX raises questions. The OS 120 AX runs great, and has lots of power, but I have seen several people who had to send it back for new bearings. One guy sent his back three times, getting new bearings each time, but the new bearings all failed within 4-6 gallons of use. OS eventually sent him a new engine. You guessed it, the bearings failed within 4 gallons. Granted, he got his moneys worth, but another guy sent his back for bearings and was told it would cost him about half the price of a new engine to fix it (yes, he was still under warranty).
I don't know if the bearings are just cheap or if there is a design flaw, but I see lots of folks that need to replace the bearings on their OS 120 AX engines waaay too soon. The engines I know of have all seen lots of use and been run hard, but not abused. The guy who scored a new engine never runs lean and religiously uses after run oil and still had problems.
I'm not knocking OS, I'm just curious if this is common or is there something funny in the water out here??

LeeL

My Feedback: (1)

Wow that is strange, I own more than a few FX engines, 3 46fx, 3 61fx, 2 91fx, & 2 160fx I have never had any problems with any of them. By far the best glow engines I have ever owned.

noterman

Yeah, it's not normal for an OS engine. These are all experienced flyers. My 120 AX is still OK, but has less than two gallons through it. I did see some references to short bearing life in the OS 120 AX on the Pattern board, but have not seen any other mention of it. Mine is the only one I know of still using the original bearings, but I think it's only a matter of time.

AlphaWhisky

I was brought up on OS engines in this hobby and have no complaints - in my experience they have all been pretty good. About ten years back I bought a pair of FX 46 engines. One was installed into a KwikFli and seemed to wear out in about six months. The other was installed into an O/D sport aerobatic model and is still going well. It has had about a gallon through it in the past four months so does get regular use. They were the last 'modern' 2 stroke engines I bought - I`m now playing with mostly fourstrokes and gas engines.

I had a savage cleanout of models during a recent move and am now rebuilding my fleet. Right now I`m building a 'Fun 51' and will install an old OS 40 FSR into that. That engine has had lots of use and bearings have been replaced at least once. One of these was my first engine on starting in this hobby in 1975 and I have a soft spot for them. Before getting involved in a more serious project I intend to build a Sig Fazer from a kit that has been gathering dust for several years. I don`t currently have an engine for that and not really keen to go out and buy a new 46 AX or similar from Tower or wherever as the currency conversion rate is not good at this time.

Some short time ago I heard of an old OS 46 SF going cheap but not knowing anything about them, just let it go. In retrospect, I think that might have been a good match for the Fazer. It may still be available. I`d be interested in some knowledgeable opinion before making an approach.

Thanks,

Alan W

DavidAgar

My Feedback: (108)

I must agree. I have been flying OS engines for over 30 years and I cannot think of one bad one. I have some of the FP engines that have more fuel run through them, I have lost count of the gallons. I have never had a bad one. I have a BGX 3500 and a couple of 160 and they are dream engines. I break them in in flight, running rich of course and after 3 or 4 flights, I will then fine tune them. With the exception of my 4 cycles I have never broken in an OS engine any place other then in the air. Just another reason I love OS. Good Luck, Dave

613bobski

I have just purchased a OS 55ax (in the mail). I am going to put in my H9 Tango. I read alot of guy's are breaking in their OS engines in flight. I will run a tank through it mounted on the plane, then if no issue's I will fly it. Any opinions on this, negative or positive remarks are welcome. Also, any sugestions for what size APC prop I should use. Speed is not important, I like lot's of vertical.

Thanks.

Mike in DC

So, did OS put the needle valve back on the carb? I also stopped buying O.S. engines when they went to the remote needle valve. Ann Marie said they would NEVER go back to the needle valve on the carb so I stopped paying attention. Do you think they will go back to the carb-mounted needle valve on the .46 sized engine?