I had more success today converting another engine to biofuels, I had a Ryobi 31cc line trimmer engine I had previously converted to a bicycle motor. I converted this today to run on E85 with 4% castor. It ran better than on gas, I got smoother running, with slightly more power and speed, and the only change I made was to open the main needle about 1 turn. I'll tell you this, the E85 is close enough in energy to gasoline that the gasoline carb could be used successfully with just a needle setting change. As we know this is not the case for glow fuel. The ethanol has higher energy content than methanol, and the 15% gas has higher energy content than methanol, and with no nitro at all, which adds power but really requires a lot of volume and increased fuel flow capabilities. What's really nice is that the E85 with castor smells a lot nicer. The bike motor gives a level speed of 25mph. It's a great help uphill, very little effort is required even on like 7% grades. It's a very crude conversion, the motor is on the tire full time, if I come to stop I have to be in low gear to restart it but it only takes about 20 feet of movement to restart. I want to do one with a clutch, and a chain drive to the front sprocket which will be converted to freewheeling so I can use the rear gears to multiply the torque of the engine with the option to pedal.
On another note, I changed the oil type I was using in my Poulan 18cc leaf blower today, I changed to Amsoil 100:1 in regular unleaded gas, and that thing smells a lot better now. I think I will change that leafblower to E85 with castor as well, and the smell will be even better. I think I breathed the most exhaust fumes when using the leaf blower, the exhaust comes out the front of it so when I get to a corner of the yard or a confined area of the yard, the fumes would build up. The E85 with 4% castor is downright sweet smelling.
-Tom Andersen
Colorado Springs, CO
www.hoverbatics.com
Note this thread originally said it was a Homelite 25cc, it is actually a Ryobi 31cc.

That looks just like the Ryobi 31cc engine I am converting to RC.

Jim

You know what Jim, you're right, mine IS a Ryobi 31cc. I did the conversion to bike motor about four months ago and forgot that I got that motor from my neighbor's yard sale. The flex drive was broken so he sold it for $3. The engine runs much smoother on E85, especially at very low rpm's. It used to kick and buck a lot at the slowest speeds, but with the high octane rating of 105, that E85 fires better. I did a conversion on a Homelite 25cc a while back, it actually ran better on the bicycle downhill because it has no reed valve, the homie was piston ported. But the Ryobi 31 has more torque at low end, better for hills and larger props.

It is not the energy content that determines the carbs performance, but the air fuel ratio requirement of the fuel. It seems like you know that from the other thread. Yes Ethanol carries more energy per pound but for a given mass of air you can burn far more methanol, and the energy per stroke goes to methanol. There is no need for castor in these utility engines unless you are are using it for protection from corrosion.

Yes, I would like to find something else that blends well in the E85, maybe a synthetic oil like Klotz or Redline? That castor is very inexpensive though, even the degummed Sig AA Castor is only $20 a gallon. Compare that to the synthetics at $38 a gallon. One thing I learned about castor recently is that it has a very long molecular chain, it's quite an amazing lubricant in it's own right. And it smells nice I have some of the medicinal castor and I read somewhere it is used as an eye lubricant after eye surgery so my eyes were feeling gritty late one night so I put some drops of castor oil in them and it felt nice, a lot better than the anti-redness drops, and the next morning they didn't look as bad as they usually do after a late night of surfing RCU. -Tom

As long as you don't put Sig, Klotz, or maxima castor in your eyes, they all have additives. USP castor would be used for that.

Do you know what additives are in the Sig castor? I used medicinal castor in my eyes. It's hard to find a good eye lubricant, they want like $20 for the good stuff like Renews.

No, I don't know what's in Sig castor, but I know where it comes from.

Probably Mexico, thanks to the NAFTA treaty, no castor oil can be pressed in the USA.