Gas engine tuning for newbies....

[stommerd27]

We had a Chevy pickup on our farm that ran on propane. It was the most gutless, stinky piece of I have ever seen.

[bodofish]

	Quote: Originally Posted by stommerd27
	We had a Chevy pickup on our farm that ran on propane. It was the most gutless, stinky piece of I have ever seen.

My guess is it was probably stinky and gutless regardless of what fuel it was using. I've set up a few propane fueled pieces of equipment and cars/trucks. I can say with out a doubt that they never lost any performance. The cars and trucks were dual fuel rigs, gas or propane and unless you were smelling the exhaust you couldn't tell the difference.
One delivery truck that was switched to propane went 240 some odd K before a rebuild and the heads were as clean as the day it rolled off the assembly line. The other funny thing about propane rigs is the oil never gets dirty.

[RTK]

I can verify what bodofish is saying about propane run engines. Had a friend that ran a Ford 460 on propane. after a few hundred thousand miles on a work truck he decided to tear it down and see what it looked like. It was freaking remarkably clean.

[flatspinjim]

I can back that up also. Ford 460 with 200,000 miles and doesn't burn any oil. Can't tell any difference running on propane or gas, except gas milage drops on propane. Not a good thing on a 460! Lol

[rcgood]

	Quote: Originally Posted by flatspinjim
	I can back that up also. Ford 460 with 200,000 miles and doesn't burn any oil. Can't tell any difference running on propane or gas, except gas milage drops on propane. Not a good thing on a 460! Lol

Do you mean propane mileage?

[flatspinjim]

Lol, yeah, propane mileage.

[bodofish]

But in the end, propane would be pretty tough to mix with oil....... I haven't seen a model engine with oil injection yet. OOOOPPPPSSSSS there goes the weight again!

[Tired Old Man]

That's still one of the major issues with using a 4 stroke large enough to fly a 30% plus plane. it can be done, but how much weight do you want to add?

[renlis01]

Can someone help me out with the following problem ?

I'm still trying to get my new RCGF 20cc to run properly... After reading MFUESS doc on how to properly set the carb I was able to do a perfect fly for at least 10 minutes, when all of the sudden the engine almost quit. I was able to land the plane and noticed that it was spitting a lot of fuel when I hit the throttle. After removing the engine and the carb I noticed that the reed valve was torn ... it was not even with the whole. My guess is that this is the cause of all the gas coming out of the carb when I give throttle up.. Is my assumption correct ??? If so, I need a new reed and that is where the problem is for me !! What is that made of ?? looks like fiberglass ... I've read here that this guy used the inside of a floppy disk !! Is that really something that can be used for this purpose ?

Best regards,

Renato.

[pe reivers]

For a quick repair 'n' fly job, you could even use tin can material for reeds. Just do not expect them to last long.
Normally, reeds are made from spring steel or fiber reinforced plastics. Lots of fiber materials will work, some of our epoxy glues will work for plastic.
When you make them, be sure to press the reeds between flat plates (glass will do) in order to squeeze all excess epoxy out. use a layer of oven baking paper to avoid sticking.

[neilhut]

I have a strange problem - hope someone can help. I had a lot of guys around my plane at the field and they can not fix either.

I start the plane and warm it up. Everything is running fine and it idles great. I then go to full throttle to test ( which is fine ), but when I return to idle, the engine is suddenly reving very high at around 1700/1800 revs. If I then blip the throttle to say half way and then straight back, the engine goes back to a normal idle.

I have checked all the filters, checked the servo ( and replaced ), checked the linkage ( tight ) and tried all manner of tuning adjustments, but I just can not get it to be constrant, whether I go to idle from flat out or half.

Any clues?

[Al Lewis]

Low end is lean.

[RTK]

That would be the first thing that comes to mind, next check to make sure your servo is working properly too.

[neilhut]

Thanks. Let me give this a try and report back. The guys at the field had me going to other way :-(

[mfuess]

Throttle butterfly is slightly loose. I've seen this several times.