I recently got my first four stroke (Magnum .52). I have no problem adjusting a two stroke (gas or glow). However, I sure could use some pointers on adjustment of this four stroke. It's running good but, I am getting a black residue that looks like carbon. I sure don't want to hurt the engine. I love the sound of it, and it has plenty of power. Matter of fact, I already bought another one.

Thanks in advance Bob

I always adjust my four strokes just like I did my two strokes.

If you have a four stroke adjusted too lean it is sure to quit on you. Maybe even backfire and throw the prop?

The black may be you are running it too lean?

Use a tach and set the top end about 300 rpm shy of max. Then you won't be lean . Set the bottom so that it'll idle reliably, not load up, and transition well to full throttle.

I'm with w8ye on this one. I lean mine out then back it off a few clicks. I have yet to have a problem to date.

Tim

I don't use a tach. I just listen to the sound of the engine. I just twist the needle back and forth a few times and listen to the engine. I then make it a few hundred rpm richer.

Hi!
You set all engines by ear!! It's soo easy!
Just two needles. You start ithe engine at idle, give full throttle...then set the high speed needle...then the low speed(idle needle). That simple!

Same here. Only other thing is to keep an eye on the rpms.

If this is your first four stroke, use a tach. You can't judge whether the engine is running well without one. Once you have done the adjustments a few times, the tach becomes optional. The highe end is easier to ear tune as when you cross the max, the engine doesn't fall of like a two stroke, but just dies. It is still possible to get them to lean by ringing out every RPM you can on the ground. You want a bit of a cushion.

The black junk may be from a loose muffler. Any movement allowed will cause wear in the threads, giving off a black goo. Use some high temp silicon and give the male threads a very fine coat and then lock the nuts down very tight. If you do this, you will not have a problem with a loose muffler. If you don't, chances are very good that you are going to see wear after just a flight or two and a full failure of the head threads is possible after a while. This applys to all four strokes.

This method works on four strokes and gives you your best running engine. One thing to keep in mind with a new engine, espically the Magnums ( I own five of them from the 52 through the 91) is that they are slow to break in, and you can't get a really realiable engine for several tanks. Some say a couple gallons, but I believe that once you have run five or six full tanks through it, you can go for a proper tune. The 52 should peak out at 10,000 rpm and idle at 2500 when new, and the idle will drop down to around 2200 after things get worn in.


1. Make sure your throtle is opening and closing all the way. You don't want the low speed stop actually preventing the throttle from closing and killing the engine, you will take care of that with radio adjustments.

2. Start your engine and run it at about half throttle for a couple minutes to get things warmed up

3. Go full throttle and adjust the high speed needle for maximum RPM. When you get close, go one click at a time and count to 10 before making the next click adjustment.

4. When you find the top, go back rich and drop 500 to 600 RPM, For a new engine, I would drop it down bye 800 RPM.

5. Slowly drop the throttle as far as you can and keep the engine still running. A small screwdriver at least 8" long to make this adjustment is nice. Again, very slowly lean the idle for maximum RPM. Now drop the throttle again to the slowest it will go and keep running. Adjust the idle again. Note that when making th idle adjustments, only turn the Idle needle 1/16th turn at a time. It is very sensitive.

6. Go back and adjust the high end again.

7. One more adjustment on the low end.

8. Now, the engine is still fully warmed up, at a dead idle jam the throttle full open. If the engine stammers and stutters before gaining speed, the Idle is to rich, lean the idle out 1/16th turn. Keep going until the engine jumps to life with no hesiatation. If the engine dies as soon as you jam the throttle, the idle is to lean, open it up 1/16th turn at a time until you find the sweet spot.

9. Now go back through the setup one more time for the final adjustment. Top end and idle.

THe Mag52 has had some issues with loose Orings on the needle valves. I have one that I could not get to idle below 2800. I haven't gone back and fixed that problem yet as I picked up an O.S. 52 and was using it, until THE CRASH. I totaled out that engine, only the muffler wasn't damaged. I picked up seven pieces of the ground and still missed one pushrod and pushrod tube. Now I have an incentive to get the 52 running right.

My 70 and 91s ran sweet right out of the box. One of the guys always cautions me to slowly increase the throttle, so I don't stall it. BULL. If they won't stand a hard and fast jam to duty from full idle, they are not adjusted right. I'm still prefecting, shall we say, my landings and if I can't jam the throttle and get out of trouble, then I may loose a plane. It has happened to me, and I ended up fishing the plane out of the pond by our runway, after it clipped a wing on a fence post and tore the wing of. My problem then was trying some Cool Power fuel. Don't like it and won't use it again. The Omega 15% works very well. The Cool Power 15% gave me trouble in two different engines.

Don

Thanks guys. So from what I gather here, it tunes the same as a two stroke. I did use locktite on the muffler, as I have read about keeping the muffler on a four stroke. I used the green. Did the breakin per instructions, but wanted to be sure I was not going to hurt anything, or miss anything.

Thanks Bob

The loctite probably won't work too well on the exaust since the heat and vibration will break it down. Use some hi-temp RTV as suggested or use teflon plumbers tape. Snug your exaust down, run the engine to warm it up fully, then tighten the exaust down again. Shouldn't have problems after that.

Need Permatex "Seal Bearing Retainer" regular loctite threadlockers won't work