I have a us 25cc on gas/glow. 10/10 2:1 fuel mix. The engine runs good and strong but Im haveing some probs with the midrang.

What it will do it. I can leen out the low end and get a real good idel but but when I bring the rpms up it will die out. If I bring the rpms up slow it will come up and run stron. If I richeng it up so I can get some what of a good respons it will idle like crap. This is the only engine that I have on gas glow that will do this. what I am asking it can it just be that the carb needs work on can if just be a enging that is not good with gas/glow.

This engine has grate compertion so I know it is not that.

Thanks

Walbro says in their technical literature that the idle has to be richer than optimum for good throttle transition, and I have found this to be slightly more pronounced when running Gas/Glow. It likes a richer idle than normal. However, you should be able to work it out.

Try using one of those intake horns they sell. (You could make one.) Most all two strokes have what is called "stand off". It is a mist of fuel that is expelled out of the carb when the piston goes back down to close the intake port. With an air filter, or an intake horn, (velocity stack), the mist is drawn back into the engine. Without, that mist is blown away by the propellor, effectively leaning out the mixture.

So try that, and if that doesn't work, I would try a different carb. Also, if the carb is too big you will have this same problem.

Good luck,
AV8TOR

Ok I have a velocity stack. I will put it on it and see how it will do.. but that is the one thing I did not put in the post.. There is alot of fuel that will come out of the carb and back on the plane. Your info has giveing me light on what I need to do to fixs this.. Most of the time I fly this plane slow and bring the rpms up slow so it has not been a big deal but when the guys at the club see the gas/glow I to not want to make thim think it is all like that..

i have seen this mist before when trying to start my engine.
i didn't think it was a problem.

i tried my gas/glow conversion adapter in my second new 28cc, 11.1mm carb, twin ring, higher compression engine.
it had a smaller prop than normal because i smashed the other.
but anyway i tryed gas/glo on it and i hardly noticed any rpm drop at all WITHOUT glow plug heater!
then i tried the transition and that was the same as spark ign too!!!

now i need to get a new prop and try it with the 10/11 nitro i ordered[>:]

on spark ign it would get a 14x7 #3 blade master airscrew up to around 10,000 on ground! (engine not on plane, so no unloading)

shaun

Was this with the 10/10 glow fuel?

no this was with just a normal gas mix of 25:1!!!

shaun

Hi everyone, i have been reading this conversion thing for a while now. There is a couple of questions i have, if anyone could set me straight that would be great. I am using a 62cc sthil chainsaw motor in a drag boat. I would love to convert it to gas/glow. question 1- 1 part 10/10 glow fuel & 2 part gas. is this gas a gas oil mix or straight gas? question 2-what brand of fuel makes 10/10, i have had no luck at finding it. Thanks, Frank

Now that sounds like a good combination.
There is no extra oil needed. The 10% oil in the glow fuel is enough.

Fuel blended fot the large Super Tigre engines is a 10/10 mix and should be available wher ever ST engines are sold
and most other hobbie shops too.

Tower hobbies carrys it in quarts. http://www2.towerhobbies.com/cgi-bin...8&I=LXUU70&P=K

There is no hazmat charge for this small amount but you can but almost a gallon for the same price at a hobby shop.

The gas down under must be quite different than the gas in the US.

10% oil, 10% nitro glow fuel

It's commonly called glow fuel "For Large Super Tiger Engines" or "Super Tiger Blend". All the major manufacturers make it. Byrons, Sig, Morgan Fuels, etc. You may have to look it up on the web, and then print the page to take to your hobby shop to prove to them it exists, as many seem to be clueless about it. (Or act that way because they don't want to special order a case for you.)

Also, the 2 parts gas is as mentioned above, straight gas without oil, but it is High Test, or Premium gasoline.

AV8TOR

Great, this clears things up a little for me. Will i benifit from using a racing type gas sold at the local drag strip or will the amaco 93 octane work best? I also want to send my engine out to be modified, is there anything that needs to be done or not need to be done as far as mods for this fuel to work its best. I need to have very good throttle response. As i stated before, this engine is in a drag boat where you start from a stand still and run hard for 264 feet( 1/5 SCALE QUARTER MILE). I need lots of power for a short time, i have even looked at the rc nitrous oxide kits from nitrous express. Thanks everyone for setting me straight on this, yall are great. Frank

I recommend just high test gas unless you run into detonation problems with your setup.

Good luck,
AV8TOR

is this correct? the more nitro the more power. What happens if i go higher in nitro%? Frank

from what i belive,
nitro decreases the flash point of the fuel and allows it to ignite at a lower tempreture.
in most cases this means that it will advance the thermo ignition timbing and give more power up to a certain degree.
to achive this you need to let the rpm's accel to get this "bonus power" otherwise you'll get knocking.

i learnt somthing too
i have been running 2 part-25:1 gas/oil ratio and 1 part-10/10 nitro.
so you mean i can use straight gas and just the lube in the nitro is enough?

shaun

to my understanding the oil in the glow fuel is all that is needed. that is if your engine has needle bearings at the big & little end of the connecting rod. I think everyone is using gas to help keep the cost of the fuel down and no other mods are needed. I am not concerned with keeping fuel cost down, i like the idea of sheding the weight of the ignition system plus some added power from the alky & nitro. My motor will only be ran for a short time, so, maybe i need to run straight glow fuel for maximum preformance. Now i need a carb set up for straight glow fuel. anyone know how to set a carb up for this? Frank

I just tried gas/glow in a SuperTigre 40 last night. [8D] My mix was started with 30 percent glow (Omega 10%) and 70 percent premium grade gasoline. I had just a bit of seperation and since it is a bushing motor I added Klotz until all was blended and clear. With an OS #8 plug it would run rough when the glow power was removed and die if throttled back below about 3/4. I changed to an OS F plug and it ran quite well full throttle and would idle down to about 3500 to 4000 before it would die. If the glow power is left on it will idle down quite low and very reliably. What would be the best additive to try and improve the idle characteristics. It runs very good at full throttle, only about 300 rpm's down from straight glow. CHT is up about 75 deg from straight glow but still not horrible and if richened any to try and bring the CHT down the engine becomes very rough and sounds as though it is missing. I tried both adding and removing a head shim but removing one made it detonate and adding one made it run worse when the glow was removed. Any help would be appreciated. [8D]

The symptoms you have are that of an engine with low compression.
Now I only have experience with conversion engines.

Basically I'd add more Nitro. Try 15/18 and add extra oil.
You need to keep the manufactures recommended oil mixture.

Engines with bearings only need about 3% oil thats why we can use 10/10 in conversion engines.

More methanol in the mix...

AV8TOR

Thanks guys. I tried more nitro the next night and it detonates pretty bad so I went back to my first brew. Sounds like a car with low octane when you accelarate it from idle. Will ether help the idle? I don't have any but a John Deere dealer is right around the corner from my house. I do have some acetone, does that help idle quality?

you need more methanol in it.. that is what keeps the glow plug lit.

Hello all,
What matterial is used for a crankshaft on 2 cycle glow engine?
The reason I'm asking is I'm converting a glow to gas and want to harden the pin on the crankshaft. I'm not planning to cut and insert a new pin.

Thanks
Borna

Weren't the problems of hardening the pin in situ on the crankshaft answered in another thread:

http://www.rcuniverse.com/forum/m_61...tm.htm#6195305

What new approach are you planning to avoid the need to regrind it after hardening?

John

If someone can tell me what type of steel is used for crankshaft 1/2 of my problems are solved.

Thanks
Kam

ok guys, the spark test confirned that the crank is made of tool steel

It is pretty easy to drive out a crankpin form a weed-eater engine. Use the needle bearigs that go with the pin. Something to thinkabout!!!! Capt,n

Hi all, just tryed a stihl 62cc chainsaw motor on 2 parts gas & 1 part 10/10 glow fuel. I was also using an OS type F glow plug for 4 stroke engines. It fired right up, seem to run the same with or with out the glow starter attached, if anything maybe a hair ruffer on the idle without the glow starter attached. However, it did run rough on the idle, even cut off a couple of times. If you get the revs a little above idle the throttle response was great, trying to rev up from the rough it had was tricky an slow. Any body have any ideas on what i need to do about the rough idle? Thank, Frank