Here is some info on the .62.
Since I have started using the 20/20 blend that Bob Reeves suggested, I no longer open up the mufflers.
Bob Z.
"To many, the 4 stroke engines present themselves as a technical mystery. This is definitely NOT the case. I have been using them for well over ten years and maintain that once properly set up, they are no more difficult to use than the 2 strokes. There are a few guidelines and items to consider but none are difficult to implement or understand. Proper run-in is very important in 4 stroke engines. From considerable experience, I have found that most every one needs at least one hour of time before it’s ready to perform. Some sure indicators of insufficient break-in are high fuel consumption, as well as hot and erratic running. BE PATIENT and give them lots of run-in time!!!
My preferred fuel, with which I have had excellent results, is the Brodak 10/23 which uses a 50/50 castor/synthetic blend. People in many of the warmer climates prefer a 20% nitro, 20% all synthetic blend. Again, what yields the best results is the ticket.
Here is a method I use for all my 4S engines before I run them. I inject about ¼ ounce of oil into the breather and cap it off. After installing a prop, I flip the engine ten or fifteen times. This insures that all the internal parts are well coated. Then, I mount the engine in the test stand and remove the valve cover(s). After checking the valve play, I drizzle oil all over the rocker arms insuring that it flows down the push rod tubes. Replace the covers, remove the vent cap and we’re ready to go. Install tank and tubing with an in-line filter. This is very critical as the 4S fuel passages can clog easily.
Due to the induction/exhaust layout of a 4S, it is nearly impossible to prime when mounted upright. No problem – just choke it as one would a 2S, keeping in mind that the downstroke AFTER the power stroke is where the intake valve opens and fuel can be drawn in. Using clear tubing, you can see it being drawn into the carb. With the plug lit, turn it slowly to get a bump. It can then be started as any other engine. My preference is flipping by hand. I have done so with 4S engines ranging from .20 to .91 and once one gets the hang of it, it becomes second nature. Of course, USE A GLOVE or chicken stick. If you prefer an electric starter, make sure the engine is not flooded before engaging it. If for some reason you manage to flood it, the easiest way to clear it when on a stand it to remove the plug and flip it briskly a few times, doing so until no more fuel comes out. When first started, a lot of oil will spew out of the breather. A length of fuel tubing down to the ground makes things a bit neater.
Following the above procedure, I found the engine very easy to start and quite user friendly. A 12-6 wood prop did the trick for run-in. I set the needle valve at five turns, allowing for some initial rich running. Then, I leaned it out slightly after every tank. After around 45 minutes of running, I decided that it was ready to install. I suggest you re-check the valve clearance and adjust if needed. Most wear occurs during the first hour or so and you may never have to adjust again.
By the way, one thing was immediately apparent. This engine is a bit louder than most of the 4S engines I’ve used. You’ll note that the muffler is quite small, allowing minimal exhaust gas expansion before exiting. The small muffler does indeed save weight but should noise be an issue, just buy the muffler supplied with the RC version of the engine.
4S engines, like any type, will occasionally flood. When on a profile plane, the exhaust is normally facing down and by gently turning the prop back and forth, the flood will clear and drain out through the muffler. If the engine is inverted, do not turn it upright to clear the flood. A slug of fuel will simply ride up and down on the piston. Instead, leave it inverted and turn it back and forth until the fuel drains out the muffler. Keep in mind that the valves are at the lowest part of the engine and as soon as the exhaust begins opening, the excess fuel will run out.
Another interesting foible is their tendency to run backward. If you are running muffler pressure and your vent fitting is submerged in fuel, this is not only irritating but downright dangerous. Why? When running backwards, it is drawing air in through the muffler. Since there is a fuel feed line coming from the tank to the muffler, the muffler acts like a carburetor and will draw the fuel in. The bad part is that the actual carburetor acts like an exhaust. You will be discharging burning exhaust gases through the carburetor into the engine compartment. Possibility of fire? Yep! I’ve already seen it. Should your engine start backwards, just cover the muffler outlet and it will stop immediately.
In closing, allow me to describe something that I have done with many 4S engines and the results have been more than satisfactory. Virtually all the engines I’ve used seem to have one thing in common: An exhaust outlet that just appears too small. What I have done is to ream them out, increasing the area by about 25%. Does it work? On the SAITO 30, ABSOLUTELY. I have proven this by direct comparison on every one I fly. I did the same to the muffler of the 62. I noticed an immediate decrease in fuel consumption and it appeared to run cooler. Please realize that I am not suggesting that you perform any mods to your engines. I’m simply sharing some results and information gleaned from over one thousands flights on 4S engines ranging from .20 to .91 CID."
Topic: Saito 56/62/72 (Read 5684 times)