1bruno

Im trying to tune my Z 26 so I get a higher RPM at full throttle, I think its runnig to lean, I have a lot of oil out of the muffler pipes. Its running at full throttle currently at 6900 to 7100 PRMs and Idol at 26 to 30 RPM. How can I get this to run closer to 7600 or 8000? Or is this the fastest it will go? I have fiddled with the low and high settings and also the idol setting. Im turning a 18 x 6 prop. How do I get more power out of her. When she first starts there is a slight hesitation until to get to power, Im trying to stop this too and get more power on the upper end. Should I use a throttle curve?
Glen

freeair

firstly, is this engine fully run -in ? what fuel and oil are you using ? have you tried a different prop ? lets say this engine is run in and your using a good petrol [ gas ] good quality 2 stroke oil and the correct ratio mix, you need to get the low needle sorted out so theres no hesitation when you hit the throttle, try 1/8 th of a turn in or out until you get it right, then you work on the high needle for maximum rpms. if the prop is too big your top rpms will suffer, you say your running an 18 x 6 prop you may want to try a 17 x 8 or 17 x 10 and make sure they are correctly balanced.

mogman

I'm running a G26 ei. 40:1 mix, 18/6 APC, 8500 rpm.

arobatx

Your engine is out of tune....

Are you running the stock exhaust or some other in-cowl aftermarket alternative? Assuming you are running the average alternative, the 26 will spin a mejzlik carbon 18x6 at about 9000rpm on a few simple side dump exhausts. Very similar numbers with a Menz S 18x6. The APC 18x6 is a heavy prop for its size. The Mejzlik, Menz S, NX, or Xoar laminated are among my favorites, but you might start with a 17x6 on a new one.

If you must run APC, run a 17x6 or 16x8. Not just any 18x6 will spin well, nor offer good thrust or flight performance.

Warm engine, tune high end for peak RPM (use tach) then back off 100rpm or so.

Lean low end in small amounts, re-adjust idle rpm with TX trim and test transition between each adjustment and repeat until transition hesitates or engine dies when advancing the throttle

Now richen low end, in small amounts, re-adjusting idle and testing transtition as before, until you get a nice crisp transition.

Go back to high end, adjust for peak and back off 100 or so, fly it, full cool down, and repeat....

1bruno

Thanks, First the prop is a Zoar 18 x 6, and balanced.
Second the gas is good and the oil is Amsoil synthetic. Mix ratio is 40/1
Third, The muffler is standard.
Forth, the motor is broken in.
Right out of the box I never got the engine over 7500 RPMs.
So should I close the high and low ends and open up as the manual says and use that as the starting point? Sounds like I need t adjust the low end then the high end.
Before I go buy a new prop ill try to adjust everybody tells me that I have the correct prop.
Could I be running the wrong gas to oil mixture? Its spitting out alot ot black oil on the plane thats for sure.....
glen

arobatx

The xoar will be just fine on aftermarket exhausts, but with the stock exhaust you are likely loading the engine a bit. Regardless of exhaust or prop used, you want the engine turning happily close to or above 9000rpm. Around 9000 is when the engine gets into its happy place, load it up by choking the exhaust and spinning a larger prop and you'll never see it perform well.

My opinion is if you are going to use the OEM exhaust, change props...go with a 17x6 or 16x8. If you get yourself an easier breathing exhaust, or modify the stock one by openning it up internally, you'd have better luck with the 18 inch props.

Close both needles gently, then open 1-3/4 to 2 turns. Tune as described above. The starting points mentioned in manuals are just settings that ensure a condition where the engine will start and from there tune. Yours starts, so there's really no need to close and re-open. If you have a digital camera, pull the plug and take a good couple pics of it, post em here.

As for oil, I prefer Pennzoil 32:1, and use it in everything I own, including the lawn equipment, but I have also used a few good synthetics in the past, Amsoil isn't one of em. Some Amsoil is not designed to be mixed at 40:1, which could be a portion of your experience as well. A good picture of your plug will tell alot here.

Zippi

My Feedback: (10)

1bruno,

I'm running a XOAR 18X6 prop with Pennzoil 32:1. I only have about 1 gallon of fuel though my engine and I'm getting about 8200 rpm. I'm using a B&B Specialties Header Pipe on it as well. I'll still need to tweak on mine as I know it will do better.

karolh

Using a 18x6 prop on a fairly new engine with the stock muffler which is very restrictive will most definitely hinder you from getting the max rpm the engine is capable of. Just follow the advice Arobatx gave you and you should be okay.

The black goo the exhaust is spitting is a sign that the engine is still breaking in or that you are running it too rich or maybe you are using to low an oil ratio. I am of the view that there are more suitable oils for our engines than the one you are currently using, and a good quality picture of your plug would speak volumes here.

Karol

1bruno

Thanks so much for the tips Ill take a pic of the plug tonight and post. looks like I need different oil and a new muffler. What do you guys suggest?
Glen

Zippi

My Feedback: (10)

Double post.

Zippi

My Feedback: (10)

The [link=http://bennettbuilt.com/page2.htm]B&B Header Pipe[/link] is nice but a little louder than a muffler. If your muffler is going to be outside of the cowl it gives a much cleaner look.

1bruno

Here are the pics of the spark plug it looks burned and in very bad shape [sm=drowning.gif]. The engine must be running to hot... At idol its turning at 2200 RPM, at mid throttle its turning at 4600RPM and at full throttle its between 6900 and 7000 RPM/

fastinated

Looks like alot of oil. You aren't running the 100:1 oil at 40:1 are U? That could cause the excess! I ran 100:1 in my old 4 wheeler and it would barely smoke. And being a Banshee 7 years old and never had even a ring job. So in my mind it's safe.. Forward several years I'm looking here for tuning info for my G26 ei. My first gasser.