I have a Seagull Space Walker. I am sick and tired of my engine. I spend more time getting the engine running right then flying. Half my flights end up with dead stick landings.

What is a good reasonably priced 4 stroke engine that is comparable in power with an Evo 46?

Thanks,

Wings

A Saito .56 or .72

I'm not trying to be rude but the Evo engine line are some of the easiest engines to run and are virtually newbie proof right out of the box. If you can't get your 2 stroke engine to run reliably, I have doubts that you will be able to do so with a 4 stroke engine, which cannot be tuned for best performance without the use of a tach-its impossible to hear the 300 rpm drop from max lean rpm on the rich side with your ears, unlike a 2 stroke.

Yeah 4-strokes are not known for their simplicity. They are known for their torque delivery and cool scale sound.

I have been running an Evo .46 on my test bird the last 2 weeks and it started and ran right off the bat. It did take a little breaking in, but it ran the whole tank full even on the first start, which, by the way, was a 1-flip, hand start. I changed to a 12.25-3.75 prop this weekend and had to re-adjust the needle, but before that, except for a short bench run, I hadn't changed the needle setting. You should always set your engine for a slight smoke trail at the first of the flight because it will lean out as the flight progresses and fuel is used.

4-strokes are ringed engines and will require a rich break-in. You shouldn't drop then in a plane, start, lean out and expect a good run. Saitos, in particular, take a couple of gallons to really come in. I normally run mine with a half gallon of break-in fuel containing extra castor using the Saito specified break-in procedure, then use Omega 10%, castor blend for another gallon on a plane. Later I may switch to a 20% heli blend for more power.

If you are trying for the last rpm on every flight, you really don't want a 4-stroke.

I have two evo 46's.

In the beginning they were great! No complaints at all.

Now neither one of them run worth a crap. One has been crashed and is in rough shape, so that one is excused...

I just bought the other one early this spring. It ran great at first.

Now not only will it now run correctly, it has developed a nasty "knock".

I never run it lean, I should send it back.

However, I appreciate your warnings of not getting a more complicated engine to run, it is not my lack of understand of how the engine works that is the problem.

I have and several people at the club including the club president try to trouble shoot this engine and all come to the same conclusion I do. WHAT IS WRONG WITH THIS THING!

Maybe I just have a lemon, because my first one never gave me any problems untill I power drove it into the ground.

I think I am going to just buy another evo engine that I will replace the one that was crashed and I will send the other one back for the experts to look at.

I have to drive an hour to my club's field, so I can only go on the weekends. It is so frustrating to drive all the way there and fight the engine all day. For once, I would like to fly! This has been happening every weekend for the past 3 weeks!

Thanks for the help guys,

Wings

Wings,
Since your time is limited and Saito's need a farily long rich break in, you may want to consider a better 2 stroke engine. I highly recommend the Thunder Tiger .46 or OS .46 AX. Both are reliable and have a great reputation. The EVO's are from mainland China I suspect and you may have gotten a bad one.

Don't Evolution engines have a 2 year warranty?

Hi!
You say that your engine "knock"....thats typical...if its the type of knocking I think of...of an engine running to high compression/too high nitro content in fuel. This makes the engine very hard to set.....nearly impossible.
Use just 5-10%nitro fuel and a OS 8 or Enya 3-4 glowplug. Prop for a trainer/lowwinged sportairplane at sea-level try a 11x6 APC.

Regards!
Jan K
Sweden

Ya, a two year warranty. I think I will send it back. I placed an order for another. I am too addicted to go without flying untill I get my engine back, lol. I know its sad....



The "knock" is very bad. Bad enough I get comments "Sounds like your engine is about to fly apart."

I usually use 15% fuel. The last gallon I bought was 10%. Although the "knock" was still there and I still had a bear of a time keeping it going, when it was running decent for a couple of flights I didn't notice any less power with the 10% as with the 15%.

I think I have been wasting my money on 15%. Is there supposed to be a noticeable difference?


Wings

Hello!
It depends on what engine you have. Most sportengines run good on just 5%-10% nitro.
"Knocking" or pre-igniting could also be aggrevated by using too large prop and bad plug. Try a 11x6 APC and a Enya 3 glowplug and see what happens......

Regards!
Jan K
Sweden

Wings, I use 15% only because it burns better in my 4 strokes and I like having only one type of fuel. For a 2 stroke, 5 - 10 % is plenty.

As far as 4-strokes go, don't believe any of the hype about their maintainance. I have mostly 4-strokes, and they ae no more difficult to run or maintain that a 2-stroke. And you DON'T need a tach to get them to run right.

If you WERE going to get a 4-stroke, I would recommend getting something in the 70 size range. While a 52 would be plenty for your Spacewalker, you'll find that a 70 will give you a much larger selection of planes to move up to in the future.

Except for adjusting valves, bent push rods, burnt valves, etc. Granted those things don't happen often, (except for adjusting the valves), but you never have to do them on two strokes.

And I have never had to do, or had happen, any of those things on any of my 4-Strokes.

Well I have to adjust valves during and after break in and about every six months for all four strokes. Have bent pushrods, and a broken rocker arm cradle. This on just three engines. Though the bent pushrods were my fault, put the valve cover on backwards.

Thanks Minn,

I am actually in the process (have been for several months) of building a CG Super Chipmunk. I have all
intentions of using a four stroke with this plane. After reading some of the above posts I was starting to doubt that decision. All I need is to fork out more dough for equipment to use the four stroke (such as a tach).

I have been trying to do some research on four strokes to make an intelligent choice as to what engine to use for this plane. Several people have told me an OS 90.

I want a good quality engine that will move the plane around with authority. It doesn't have to be the fastest, or have outrageous thrust, but it must be dependable and last for a while. What is the CHEAPEST engine to fit this criteria? It would be nice to stay around the $200 range, but I realize that probably isn't going to happen.

What would you recommend for this?

Thanks,

Wings

Don't let the extra maintenance scare you. It isn't that bad. IMO a four stroke is the right choice for a scale plane. Flys and sounds more real, but with enough pull to do every maneuver.

Wings:

Looks like Minn is out to lunch (Supper?) so I'll give you my answer, and I really think he'll agree.

If you are truly price limited, or just want an inexpensive four stroke, stick with the Magnum engines. They are the same design as the OS for a lot less money. And they have chromed cylinders instead of the OS nickel plating. That alone makes the Magnum a better buy, in my opinion.

If you can spend "OS Money" don't consider the OS line, get the Saito instead. Far better engines, and depending on the application, I'll take the Saito over the YS too.

Bill.

Thanks Bill,


I trust that what you are saying is true because you have tons of experience with these things. But can you elaborate on why Saito's are better then OS's?


I hate to make a large investment (yep, 300 bucks is a lot for me) without making a well educated choice.


Thanks Bill,


Matt

Matt:

First, let's take the Magnum-OS comparison.

It's an open secret that SY Machinery Company, in Red China, copies the OS engines almost exactly, 99% of the parts interchange between similar engines from the two companies. The only real engineering difference is the SY engines, Magnum, ASP, and others, have true chrome plating in their cylinder liners while OS is using nickel plating.

OS has had problems with the nickel peeling in their two stroke engines, I've not heard of a problem in the 4s engines, but it is one thing that puts me off OS.

Back to the OS-Magnum comparison. Since the engineering is the same, and the parts interchange, why would anyone spend $300 or so for the name OS when the exact same engine, other than the name on the side and the cylinder plating, can be had for $200 with the same warranty?

Additionally, you wont find anyone complaining about Hobby People's (Magnum) service, but rather what you hear are loud praises.Tower (OS) service has had questions here on RCU.

The only OS engines that are not matched or exceeded by another maker is their flat four cylinder Pegasus, and the Wankel 30. Or at least that's my opinion.

When we get into the higher priced engines, you have only two to consider;the Saito line and the YS engines.

The Saito engines are very light. The FA-180 for example, with muffler weighs less than the OS/Magnum 1.60 without muffler. Really high power to weight ratio. This is also a point that causes some complaints; being so light they have a greater apparent vibration than the heavier engines. The Saito engines aren't hard to break in, and when ready for flight are easy to adjust, hold their settings, and run forever. And they don't burn a lot of fuel considering their power. They generally burn less than a two stroke of comparable size. And they are happy with low nitro fuels.

The YS are generally considered the most powerful of the 4s engines, and with reason. They are the most powerful ones. Also the most expensive ones, and they have an undeserved reputation of being hard to adjust. Follow the instructions, they purr like kittens.

So. My opinion. Inexpensive, get the Magnum engine. For hot sport with less consideration of cost, it's time to get a Saito. All out blow 'em out of the sky power, bite the bullet and buy the YS.

Bill.

That was great information Bill,


I think I will lean towards the Magnum for my first 4 stroke then.

So SY is a chinese company that produces Magnum Engines and YS is a different company all together that makes killer four strokes? I am a bit confused, but I think thats what you are saying.

I guess the Magnum is like getting the generic Advil at Walmart..... Same thing, just a different name and cost 2/3?


Hopefully I can get this Chipmunk together before the end of the season. But I just can't get in the mood to sit in the (un-airconditioned) garage for more than an hour or so. I am almost ready to start putting the two wing halves together. Maybe things will speed up after the wing, it looks like the most time consuming part other than covering.


I really appreciate the insight Bill,



THANKS!


Wings

Matt:

A little more on SY Machinery Co.

In addition to the Magnum and ASP engines they have an engine line marketed in the rest of the world as "SY" engines. And they are the factory that builds the RCV engines for the British company. I think they make the MECoA and GMS engines also, but not sure on those two.

Bill.

William,

You seem to be talking about four-stroke engines, yet you talk about the cylinder plating.

I saw this also come up in an OS.50SX thread.

The two-stroke, tapered-bore engines from OS are ABN, while their Sanye China clones are true ABC.
But the four-strokes from both manufacturers are endowed with a hardened steel sleeve.

It could be chromium plated and is, especially in many popular gas engines, but I don't think any of the four-strokes are even claimed to have a chrome plated sleeve. YS has a nickel plating, but it's in a more durable, Nikasil like process.

The OS.50SX has a simple steel sleeve also.

Most cast iron ringed engines are set up this way.

I do know that the Satio line uses chrome hense the AAC designation in their literature.

Dar:

The OS twin, four, and five cylinder engines do indeed have steel cylinders, with the cooling fins machined as integral parts. These are all four stroke engines.

The single cylinder OS four stroke engines have a brass sleeve inside the upper part of the aluminum crankcase, the cooling fins are part of the crankcase casting. The pistons are ringed. And unless OS has gone back to chrome plating, the brass cylinder sleeves are nickel plated. Only the multis have steel cylinders.

Bill.