Hi guys,
I am somewhat new to this hobby and need some opinions. Iam putting a GP Spacewalker
together and am wondering what engine to use, OS 91 Surpass, or Saito 100? This is my 2nd
plane, learned to fly with a Hobbico Superstar.

Hello, I know from the forums that I have read on RCU most people prefer saito but I like OS. I have a saito 91 and a OS 91 I like the OS because I never touch the needles. It runs great every time on the other hand the saito took about half the summer to get adjusted. Now it runs good also I have a 65 that is three years old and had to replace the bearings.This is my opinion and Iam sure the saito guys have favorable opinions as well and I respect that.

I have run both Saito & OS I have a Saito 100 now in a WACO Biplane and love the motor. The power is great! Nothing beats the sound of a SAITO. Either one is a very good motor...

I agree with CHRISTENEAGLE. I too am srictly an os man. No problems with my 1.20, two 91's and a 91 pumped.

Gunny

Both the OS and Saito are good engines. I had a Saito 100 on a plane for a while, then I removed it to put on another plane and put a new OS 91 4S in its place. The OS is heavier and is not nearly as powerful as the Saito 100. My two Saito 100s took no longer to break-in than any other four stroke that I have used. Either engine would probably work for you but you might also consider the Saito 91.
Fred B

I have a GP Spacewalker and it started out with a Saito 100, great engine but not enough for ME in this plane. I switched over to an OS 120 and have never been happier. If your going to put in any engine smaller than a 120 you are going to have to add a bunch of nose weight, in my opinion that weight might as well be in the form of usable power.

I have 10 4-stroke engines Saito, OS and YS, everyone of them is a great engine as long as you put them in suitable airframes and are familiar with the operating differences of each engine. You can't go wrong with any of them, no matter what anyone says.

All of the four stroke engine brands are good. I really like my Saito 91 and Saito 90TS. Both are strong, the twin is very, very sewing machine smooooth. The Saito 100 is said to be a little rough running but that may change after a few gallons of fuel. The Saito 91 is happy with a APC 14X6 wheras the 100 is happy with the 14X8.

I know that Horizon gives very good service on their Saito engines. I have never had any problems with bearings except for a OS 160FX front bearing that has a little play if you wiggle the prop tips. It still runs fine but I will probably replace it anyway. I always run Byron fuel and never have any rusting problems.

With any manufacturer you can get a defective part or lemon. I think with the less expensive brands you run a higher risk of this. It is the reps service that wll make the difference.

I had the Saito 90TS in my Spacewalker with a Higley heavy hub and thin nut with a Cline regulator. I also built a motor box to move the engine as far forward as possible for balance. The plane was a joy to fly and it flew very scale. You could do hammerhead turns, loops, and cuban eights but had to dive to get the power to go over the top. It was really cool. I have a OS 160 twin in it now and is grossly over powered and feels much heavier to fly but is still at 10-11 pounds. This engine is also very nice and smooth, there are several used for sale at this time in the marketplace

Have both, love both. You can't go wrong.

Yak

The Saito engines do take a little longer to break in but they are still good out of the box and only get better with age. I have well over 16 gallons though my 91. It runs flawlessly and is stilll very powerful. 10,300 rpm APC 14X6, Byron 15% nitro 18%castor/synth blend.

Thanks for all the valuable information, guys. I think I will go with the O.S. 91 surpass on this one.

One thing to also consider, I believe the OS is slightly heavier than the Saito. So if wieght is a concern, you may want to re-think your choice. I have OS and love them. Guys in my club swear by Saito. Ask 10 people...get 10 opinions.

I think as a second plane and first 4-stroke, an O.S. is the better choice... Then when you get a little more adventurous, go with the Saito or Y.S. The O.S. is the japanese cars of R/C engines, may not be the most powerful, most sexy but they get the job done very well with as little hassle as possible. Can't go wrong! And talk about lemons, the gamble is much less with O.S. Just my 2 cents.

4-strokes I own
O.S.
Y.S.
ASP/Magnum
Saito

I am flying my Spacewalker with an OS 91. It flies well with plenty of power. I considered a Saito 91, but in this case the lighter engine doesn't help. My Spacewalker required six ounces of lead on the firewall to balance with the OS. The Saito 91 found a home in my Hog Bipe.

I have a Saito 72 and it drives me crazy! It runs great, sounds great, performs day in and day out without any problems BUT that breather nipple on the bottom spits out junk all over my plane. I understand that the OS does not have that design. I don't have an OS 4 stroke but would like to know if others have this problem with their Saito and if the OS does the same thing.

signed Happy but frustrated!

Sheldon

My 91 OS has a nipple on the bottom for a crackcase breather. I used a piece of fuel line and routed it over to the exhast side of the plane. You have to clean that up anyway so it is no big deal.

My Saito 91 just finished drinking its first gallon today and it just starts with a flip or two. I opened the the box and mounted it and have never touched a screw other than mixture. Runs awesome! Saito has a better market resale value as well.

I have an OS 91 with pump and also an OS 120 with pump, and both engines do not have breather nipple on the bottom. Also, none of the YS four strokes have breather nipple.

All of the no-nipple engines you named have pumps. Do any of your no-pump engines have nipples?

Sorry, I don't have any non-pumped engines. I only use YS and pumped OS.