Fox 2.4 Tuning Help
 

I tached my Fox 2.4 gas engine and I was barely getting 7000 rpms with a 20 x 8 pro zinger. I was expecting to get about 7600.

Let me know where the needle setting should be on the high and low speed needle for optimum performance.

What kind of 2-stroke oil and what ratio (32:1, 100:1...I don't know) I should be using.

This thing is a pain in the butt to start too. What is the proper technique to start this engine.

What is the best prop?

It's my first gas engine...that why I have so many questions.

Thanks,

SINYFLY

Fox 2.4 Tuning Help
 

Sinyfly - did you read the instructions manual that comes with the engine - it covers all your questions above. Someone else's needle settings are not going to help you except to get you ballparked - too many variables - prop, air density, temp, etc. If you don't have the instructions manual, download it from Fox. Then if you have questions, let me know.

Lynn

Fox 2.4 Tuning Help
 

That is the problem. I bought a plane with the Fox 2.4 second hand so I don't have the instructions. I should have mentioned that I guess.

Starting needle valve settings would be great. I messed with the low speed needle so much I doesn't even flip start anymore :(

SINYFLY

Fox 2.4 Tuning Help
 

SINYFLY - Per Fox:
1. Use fuel mixed at the recommendation for whichever oil you purchased and regular grade unleaded gasoline. I used Stihl non-synthetic at 40:1 for break-in, then switched to Amsoil synthetic 100:1 after 6 gallons through it.
2. idle needle should be about 1 1/2 to 2 turns out initially. High speed should be at about 1 turn out.
3. Starting when cold. Ignition off, choke on and engine throttle wide open, turn the engine through compression strokes until the carb pumps fuel up through the fuel line to the carb. Set throttle at idle (make sure it's at idle!!), turn ignition on - flip prop until you feel it "bump" or actually start. Choke off - restart - should start in 3 or 4 flips. When warm, should start without choke on first or second flip. Absolutely use a chicken stick or extra heavy leather glove.
4. Don't turn the engine more than 7500 rpm, preferably around 7200 max - a 20x10 or 22x8 is a good prop to start with - you will need to re-prop as you break in and it picks up rpms. Good luck!

Lynn

Thanks for the replies
 

I think the fact that I was using Poulan Synthetic 2-stroke oil @32:1 may be the culprit too. I just placed an order for some Amsoil 100:1.

OK....I've got new needle settings, new oil coming soon. What types of props run the best on this engine?

I tached my engine using a 20x8 Pro Zinger. I also have a 20x10 Pro Zinger. Are these the best props or should I use something else like a Menz or Mejzelk?

SINYFLY

Fox 2.4 Tuning Help
 

I'd be amazed if your Poulan oil caused your engine to run significantly slower. It's very hard to measure a repeatable difference in rpm by switching between brands of oil. Less oil does not create more power, despite what same may believe.

Some props pull a lot better than others. You can't tell how good a prop is by what rpm your engine will turn. You just have to make sure your engine turns in the right rpm range to make it happy. Try a 20x10 Mejzlik or a 20x10 Airwild NX or a 20x10 Menz-S.

Fox 2.4 Tuning Help
 

Hey SINYFLY
I have a Fox 2.4 on a H9 US, and the best pulling prop I have found Is a Mejzlik 20x9. This engine Is very easy to start!
Good luck with It.

Doug