I't seems I can't get a magnum 91 4 stroke so how is this engine from os? I can get this one for $240.00 shipped. The more expensive version has a pump,is this a fuel pump? I'm new to 4 bangers this will be my first. http://www3.towerhobbies.com/cgi-bin...?&I=LXSY82&P=0

Here is a link to all the tower 4 strokes 60 to 91 size.Is there a reason Tower does not have the saito line of engines? http://www3.towerhobbies.com/cgi-bin/wti0093p?&C=GCI

Horizon Hobby sells Saito

The OS 91 Surpass II is an excellent engine. You will not be sorry.

OS .91, great engine!! Pumps, all my four strokes are now pumpers except one, an older OS .91. Pumps allow you to place your fuel tank just about anyplace you like in the air frame, I like mine just a tad forward of the CG for ballance reasons. They also keep a positive fuel pressure at all times to the engine so you aren't running lean and rich during stunts or higher or lower G forces. I like pumps!!!! I just don't care for the prices of the engines now days!![:@][:@]

yea horizonhobbies sell saito stuff, its just a turff war thats been going on for decades. Tower sell futaba and OS stuff, horizon sell saito and JR stuff. I have the .91 Surpasss 2 and its a great engine. I've never had to electric start it, it kicked overby the third whack with a chicken stick every time. BUt I also reallt like my saito 100. There really light.

So would I be ok using the OS 91 without a fuel pump?I would be using it on a 4 star kit and with two little kid's money is kinda tight right now but I really do want a 4 banger,just don't want any problems. Is OS the only one's that have the pumps on the egines?

I have this engine on a four star without a pump

I wouldn't have it any other way

I've got one on a Hog Bipe. It's a very NICE engine and I love it!!! it's got more flights on it than I care to count!!!

Ken

If you can afford the pump you wont be sorry I have two OS 120 III with pumps and I love them!

Mine is in a very old 60 size Kaos, it would be perfect for the 4*. I think it has as much or more tug then my Saito 100 had. Great engines!!!

The OS 91 Surpass II seems to be able to pull the same props in the air as a Saito 100

I use the 14/6 to 14/8 props with the OS91 there rock steady runners,I have 4 of them 3 are non pumpers 1pumped they all are good,I also have 2 of the pumped 120's there very dependable as well.

I would absolutely love to have an OS four stroke. I personally would go without the pump as I have seen how they upgrade their engines and owners are no longer able to find parts for their outdated pump. A pump is great for applications where your tank is either at the center of gravity, or in an awkward spot. They make aftermarket pumps for stuff like that for $30-$60.

I have bought 4 OS two strokes in my first year of flying, and while I never want to spend the extra money for OS, I'm always glad I did. It doesn't take long before you forgot how much you paid and you realize how much you love your OS.

I think OS comes out to be less expensive than Saito with the Tower discounts, especially if you are in the super savers club.

Joe, the pump OS is using has been used for years and years. It replaced the first one they used that was a metal unit, I have a 1.20 with one of those too. The pump is not anything that can be fixed by the owner. {sorta} If they gunk up with castor the owner can clean them and get them going again. It's a replacement part. There isn't anything in there to really mess up so the pumps don't go out very often. The big tic me off is the regulator!! There is really nothing in there either but there is a diaphram, a cheap little black item that any four year old could replace!! You can buy a new regulator cover from OS but they will not sell you a new diaphram. They want you to send them in the complete carb so they can check it out and replace that 50 cent part OR replace the complete carb with regulator!!! I need a new diaphram in one of mine!! Because of this and the new and improved price of the OS and Saito engines I question why anyone would buy anything other then a YS?? However, I get a few guys that feel they need to pay me for my help/work and I get a few OS four strokes given to me. I love the OS engines and will take all that I can get! The .91 is on the top of my list, wish someone would give me one of the older 70s, I sold the last one I had and that was another one I like as much as the .91. There, I vented!! Anyone have a diaphram for a OS 1.20 they don't need???

No, but I've got an extra Perry VP30 in my box

that pump is for 2strokes for 4 strokes you need the VP-20

the four star should allow for ideal tank instalation so the pump may not be as necasary...still nice though.

do you have the plane made. magnum didnt discontinue it, they are realeasing one that has a blue head cover, but other than that its no different. so if you dont need it now i would wait and see if it comes back in stock.

OS is one of the top engines around,superiour to magnum ,by a ways..
Dont call them 4 bangers,they are 4 strokes.
A four banger is a 4 cylinder engine

Well I have one OS .91 FS and five Magnum .91 four strokes, and wouldn't bother with another OS. The Magnums start better, and I believe are better in every way with no less power, and possibly a bit more. I'm guessing that the carburettor has been changed from the OS design, hence making starting easier, and possibly the reason for a touch more power.

Magnums are last year's OS engines, but I think that the Chinese company (SY Engineering??) makes a few mods as well.

Magnum is the engine for me, and a bonus is that they are way cheaper than OS.

I only know the Magnum XL .91 RFS by reputation, and that reputation is very, very good. It's a strong, reliable 4-stroke that is by most reports a very good value. I own a couple of the Magnum XL .52 RFS engines, and I think that they too are strong, reliable, and a great value.

I also own a Thunder Tiger F-91s. It is available from http://www.thundertiger4u.com for $194.99 with free ground shipping included. The Thunder Tiger F-91s is a couple of ounces heavier than the Magnum or O.S. .91 four-strokes, but it is very powerful, reliable, and easy to tune. I really like mine and I won't hesitate to buy another when the right project comes along.

I don't believe that anybody offers a bad choice in four-strokes, it's simply a matter of matching up your project to your budget when deciding which to purchase.

Good luck, and good shopping!

I would a loved to start of with a magnum but I don't know when they will be out again,you would have thought they would still be producing the old line of engines instead of stoping production on them.who even cares about a blue valve cover,I think I would just paint it black anyway.

You will love the OS if that's the route you decide to take. You can read reviews [link=http://www.rcuniverse.com/product_guide/EngineRatings.cfm?engine_id=88]here.[/link]

Edit: just for comparison, [link=http://www.rcuniverse.com/product_guide/EngineRatings.cfm?engine_id=361]here[/link] are the reviews for the Magnum.

I know which one I would buy.

Wow great review for OS,the magnum ain't looking to good on the review,makes me wonder.

How does the fuel consumption compared betwen de OS 91 4S and the Saito 100?

Thanks for your comments, they always have helped me.

Bill