jeff4912

Just about through my first gallon of gas at 20:1 mixture for breaking in my Evolution 15GX2 pumped carb engine.

My question is: will the HS and LS needles need to be retuned with a mixture change to 32:1 and if so in what direction usually?

CARS II

My Feedback: (7)

Here is something to get you thinking.

With less oil in the fuel then your mix becomes richer, more fuel, then you may have to lean it some.

I think.

w8ye

My Feedback: (16)

Good bye lower rod bearing!

jeff4912

.??...32:1 is the recommended mixture after break in.

w8ye

My Feedback: (16)

Smaller engines need more oil.

captinjohn

I agree with W8ye !

dirtybird

My Feedback: (5)

Oil is cheaper than rod bearings. I would wait til at least 5 gal is thru it.

ahicks

My Feedback: (2)

Understand the logic behind the hesitation to make the 32:1 move, but you guys might have a look at the manual. If Evo says it's OK, betting they've got some hours of operating time to back them up.

O.S. is saying 50:1 for their baby gasser. That's the one that has me taking a wait and see....

http://www.spektrumrc.com/ProdInfo/F...-Manual_EN.pdf

jeff4912

Fourth tank of fuel:






Select one of the recommended
propellers for normal operation
and mount it on your engine. Tune the main
needle valve to be slightly rich of the peak
RPM and the low speed needle valve for a
smooth transition from idle to full throttle
and continue to break-in the engine in

flight.



Continue to fly the airplane through the first

gallon of fuel and then change the fuel mix
ture to 32:1 for continued operation.

Right out of the Manual.

w8ye

My Feedback: (16)

"Oil is cheaper than a slung rod."

You will find the engine runs just fine on 20:1

av8tor1977

My Feedback: (6)

I agree. Sometimes the engine manufacturers tell you what they think you want to hear and/or something to be more competitive.

More oil equals:

Longer engine life
Less chance of engine damage with a lean/hot run
In many cases, MORE power due to better ring seal
Peace of mind

I use 20:1 on all my engines 20cc and under.

You could run your car around one quart low on oil all the time to save a few bucks on each oil change, but would you do it.....?

AV8TOR

hairy46

My Feedback: (1)

Will keep all this in mind when I start running my evolution / 10

MTK

I have just about 3 gallons through my OS GT15 being run at 50:1 (Bel Ray MC1 Motorcycle Racing Synthetic). At about 6 ozs per flight we're talking around 60 flights or around 10-11 hours of operation. Not a lot of flying for certain, but not too bad either. The engine is still pristine. It's the ignition version not the glow

ahicks

My Feedback: (2)

Thanks Matt. That helps bring some merit to the idea these little guys may not need all the oil I thought they did. Will still be giving that story plenty of time to develop though. I have an open mind when it comes to stuff like this, but some ideas are harder to change.....

Others, running on the too much oil never hurt a thing, makes your engine last longer logic, my engines will likely out last me as it is. Why waste the oil, and being purely lazy here, the extra wasted time wiping that extra oil off the plane if I don't need to? I'd rather be flying! -Al

spaceworm

I think you have to consider the possible differences between the two engines. I don't know, and frankly don't care what those differences are, but if one has roller or needle bearings on one or both ends of the con rod, and the other not, then the issue of oil ratio becomes an item to consider. Other considerations also may apply. JMHO.

Truckracer

My Feedback: (19)

Most if not all of the newer, quality small 2 stroke gassers have needle bearing on at least the crank end of the rod. The piston end is far less critical and a needle bearing there is a plus. As far as oil ratio, I say run what you want to run .... its your engine! I use more oil than recommended in all my engines but that's just me and my preference based on past experience which may no longer be valid. I've never had an oil related failure and I never plan on having one. Some oils, even some of the well known synthetics will tend to coke up the exhaust system but I no longer use those oils. But even those oils worked well inside the engine.

ahicks

My Feedback: (2)

Spaceworm - just an FYI. The baby Evo rods do have roller bearing big ends.

http://www.horizonhobby.com/connecti...10gx-evog10204

That's not to say though, that the same metallurgy is in play regarding the crank pin (O.S. vs. Evo). Not discounting your point at all.

Truckracer-

" I use more oil than recommended in all my engines but that's just me and my preference based on past experience which may no longer be valid."

That's my plan as well, but I have an open mind when it comes to "staying valid". When a new thought or idea comes up, it will normally have my attention right away. If evidence shows the new idea works and has merit, I have no trouble switching to the new plan at all.

From what I've seen and know of you, you're the same way. As usual, believing we're on the same page....

Gizmo-RCU

My Feedback: (27)

GOTTA LOVE IT, another debate about oil!!!!!

Truckracer

My Feedback: (19)

Well Gizmo, as long as there are RC gas engines, there will be debates about every part of them including their fuels and lubrication. At least this isn't a debate about brands.

jeff4912

Back to the original question, does anyone have an answer?

ahicks

My Feedback: (2)

Jeff, if you're thinking you can tweak the needles prior to the first flight on the new mixture to eliminate further concern, I don't think that's a good plan.

All else being equal, less oil = more gas. As the amount of air mixing with that gas won't change, that should leave you with a richer mixture.

The question will be how much richer. The only way that will be answered is by flying it.

Gizmo-RCU

My Feedback: (27)

Truckracer, think I don't regonize that? It's kind'a amusing how this subject never seems to be settled?

Truckracer

My Feedback: (19)

CarsII answered the question in the first response. The adjustment will be very little.

Truckracer

My Feedback: (19)

With a constant flow of new users and new products, its only normal for questions to repeat. I don't see a problem with that though on occasion, some people post new questions in a new thread when the question was answered within the last few days in another thread ... so it was clear the poster never researched the subject before typing a repeat question.

I don't see that being the case here. Jeff4912 had a valid question and a timely one with the new smaller engines coming on the scene.

spaceworm

Thanks to W8YE