CB36

Hi;
Just got bact to R/C after 8 yrs or so. Bought a new Saito 82 and put it on a CG Tiger 60. The prop is a MS 13X8 and the fuel is Tower 4 Stroke, (15%). Most of my previous experience was with 2 strokes.

I've put ~ 5, 10 oz tankfuls through the engine and I'm not satisfied yet that it's reliable enough to fly, (I'll need reliability as I haven't flown in 8 yrs!!).

It seems to idle OK, (2400 RPM), but I can get no more than 9600 at top end. If I lean it out a touch, it'll run for a short while and abruptly stop with a sort of bang and loosen the prop nuts. Seems hot then. Also, the beast spits a lot of wet exhaust and lots of junk out of the breather. Is this normal? Am I over propped? Have I not given it enough time for break-in? (Wow, lots of questions!).

I do not have any experience with 4 strokes, so any help will be deeply appreciated.

pbunn

My Feedback: (1)

I just got a new one myself and am breaking it in with a 14-4. I am not an expert but you are not doing it any good at all by leaning it out until it stops. I ran about 6 tanks through mine - starting at about 4000 RPM max and working up - runing very rich. After 5 tanks , very rich I started leaning it out. I now am ready to run it in the air - still a bit rich about 600 RPM below max. I have plenty of power - If I remember - correctly running about 9600 rpm with the 14-4.

daveopam

My Feedback: (9)

It is to lean on the high speed needle. It is dying and throwing the prop when it detonates or pings. You should be OK on the prop size. I flew two strokes for years. It took me several months before I could tune a four stroke by ear. You need to run it up and watch the tach. When it maxes the RPM out richen it up until it looses 300-500RPM. This will set the high end. 9,600 is a good RPM for a new .82 with that prop. If you have not leaned the low end you need to. Saito will normally ship their engines with the low end way rich. Lean it out 1/8 turn at a time. Checking how it transfers from low to high between each adjustment. When it gets to where it stumbles when you advance the throttle. Then richen it back 1/8 turn on the low. Even when set properly it will spit oil out of the breather. Just put a length of line on there and direct it out of the engine area. I try to zip tie mine to the pressure line on the muffler. Then the exhaust carries away some of the residue.



David

CB36

David;
Thanks!
As for the breather, that'll mean routing it from the bottom of the case, up to the muffler pressure line? Is it OK to route it up? This sounds like a good idea, as it'll help keep the goo off the bottom of the fuse.

wcmorrison

My Feedback: (2)

Perhaps no one has advised you that a four stroke engine does not turn up high RPMs like a two cycle engine. Around 10,000 RPM static is near tops, the engine may turn more in the air but you can expect a four cycle to top out around 12,000 max in the air. You need to set the high speed carb needle with a Tach, listening to the engine will not work. Once you get a good top end stable RPM, richen the needle (turn it out) so that the engine drops three or four hundred RPMs. Then attack the low speed adjustment. New Saito's come with the low speed adjustment flush with the the throttle arm. That is a rich setting and you should not mess with it until at least a gallon of fuel has been through the engine. Do as "daveopam" says, turn it in an eight of a turn at a time. You may have to make a number of adjustments, always going back and resetting the high speed needle valve as stated above. If you are getting a good transition and mid range operation you are near right on. If you are not getting a good transition, then richen it a quarter of a turn (out).

Since four strokes have more torque, you should use a prop that has a higher pitch to make use of the power. I would imagine an 82 would swing a 13 X 6 prop or a 12 X 8 prop real well. Use the K series Windsor props as they are designed for four stroke operation. Experiment a little and you will find a combination that suits you well.

And I have not had a problem with a rich running Saito; I have had a problem with a lean running one. You get all kinds of problems like overheating, kicking off props and so on. Treat it right and it will last for years.

Cheers,

Chip

Flyboy Dave

My Feedback: (21)

I think it's over propped. Try the 12-6 MAS K series, or the 12-7 Zinger wood.

FBD.

Ernie Misner

I am with Dave, especially for break in. The 8 pitch is asking a lot of a new engine, and on the ground. Personal preferance, but I like to go easy on a new engine and not ask too much of it right off the bat. When broken in it will unload in the air and the 13x8 is definitely a recommended prop for pattern style, but not so much for slower 3D type flying. The Tiger 60 is a great plane, as is the 4* 60. They will fly fast or slow, but I'd probably have a 14 or 15x4W APC on there and be having fun close in with it.

Ernie

Flyboy Dave

My Feedback: (21)

I use the 12-8 MAS K series on my .91's FS engines. The K series is a wide blade
four stroke prop, and is harder to turn than a regular prop of the same size. Is is
wise to use a "smallish" prop for break-in if you don't want to overheat the engine.

After the engine is broken in, you might try a bigger prop.

FBD.

edgeman55

My Feedback: (25)

14X6 APC is a good sport prop to run on this 82.Should see close to mid 9000's on 20/20 fuel.

NM2K

My Feedback: (14)

I would run a 13x6 for break-in, but if kept nice and rich, a 14x6 would be okay too.

Unlike two-strokes (I'm talking to the original poster), four-strokes must be ran a bit "wet". Exhaust drool is a good sign with a four-stroke. Since it only fires every other revolution, even with lots of exhaust drool, you will discover that your engine is really easy on fuel consumption.

If your engine was new, it came with the proper procedure for initial running. Yes, it is a PITA, but it will lead to a long lived engine. Be sure to use fuel with a little castor oil in the lubricant mix.