Good day all,

Glad to see this thread is still running strong with many good observations and ideas.

Haven't had much opportunity for much test running but I managed to squeeze in a wee bit. With the literally hunderds of possible permuations of fuel component percentages, I thought it might be best to reduce some of the variables and improve my own consistency. With that in mind I took the time to rebuild a 40 year old PAW 2.49cc DS that I had and was going to rebuild anyway. You can see my results and comments here if you wish:

http://www.rcuniverse.com/forum/m_4610628/tm.htm

I was also finding it very frustrating to try and maintain any sense of accuracy using my scratch calbrated re-cycled glass Sig Dope jar that I using to mix fuel with. So I splurged and got a suitable glass graduated cylinder for mixing. It won't help my engines run any better but it will certainly improve my consistency when mixing fuels.

I also picked up a little remote reading thermometer like the car guys use. I realize that their absolute readings will be suspect but their relative measurements are consistent (that is, it may read 200 when the actual temp is 220 but it will read 200 or nearly so each and every time under the same conditions). All this talk of our engines running hotter or colder has all been very general, now I will be able to subjectify "hotter", "warmer", "cooler" etc. And that brings up a good question, just how hot to our little engines run? The car guys claim their engines run about 220 to 250 degrees F. That seems "hot" in relative terms but that is where they run them and on 8 percent oil to boot. I was chatting with a local serious car racer the other day and he mentioned that he used fuel with 8 percent oil and has never had one fail.

I am also going to keep better notes, including ambient temperature, pressure and relative humidity.


So, some of my test results so far. I have managed to run an engine on straight oil and kerosene but didn't take any notes, just trying to see if I could do it. So I will work my way down in ether content and oil content in steps and see if I can add anything to the overall good of this discussion.

Test 1 - my normal diesel mix 35% John Deer Fluid, 35% kerosene, 25 castor oil, 2.5% Amsoil Cetane boost, 2.5% marvel mystery oil

PAW 2.49CC DS Kavan 9x5 prop prior to rebuilding 8600 rpm head temperature 180 to 200 degrees F

Test 2 - 20% John Deer Fluid, 10% castor oil 10% Amsoil INTERCEPTOR sythetic oil, 2.5% Cetain Boost, 2.5% Marvel Mystery Oil, remainder kerosene.

PAW 2.49cc DS Kavan 9x5 after rebulding 9020 rpm head temperature 150 to 160 degrees F
- easier to start by hand or starter than before, steadier runs and cooler. These differences more a result from a good clean and rebuild of the engine. Ambient temperature was nearly the same as the previous test.

I decided to try the Amsoil INTERCEPTOR sythetic oil as I can get it locally at Canadian Tire and is less expensive than the Klotz stuff the local hobby shop sells. Since I am mixing with Kerosene the ability to mix with alcohol is of little consequence at the moment. This test showed notably less oily exhuast which was one goal and that with nearly half the ether I was previously using, starting was still easily accomplished by hand or with starter.

http://www.amsoil.com/storefront/ait.aspx

Further to do is to reduce the ether in half again and continue reduce the oil content. I am hoping that temperature measurements will alert me if I have reduced the oil too much (and sound of the engine too). Also to try some pump car diesel.

I did have another question about Marvel Mystery Oil. There are lots of posts on this product and lots of mis-information too. I am not really sure what it is. I do believe it was also (still maybe) sold under the name Redex overseas or was at least very similar. I have been putting it my fuel mixes because I think it helps the engines run a bit cleaner; in other words helps break up the carbon etc. I have a snowblower that was running rough, I put some MMO in the gas and in the crankcase and it did help it run better. All of this wishful thinking? Perhaps. Simple observations are difficult to quantifiy and good judgement is easily clouded by wishfull thinking.

All that aside, what do you think, does adding Marvel Mystery Oil (or Redex) have any benefit? Andy's post about using the Aviation oil (ashless with low detergents) is interesting in light of the fact that I did read somewhere (mis-information perhaps) that MMO was mostly detergents. This is one of the reasons I chose the Amsoil INTERCEPTOR sythetic oil, it is a 2 cycle low detergent oil. Isn't one of the properties of these 2 cycle TWC or FSO (or whatever designation they have) is to burn cleaner and leave less deposits? Kill two birds with one stone, if these synthetic oils burn/run cleaner with fewer deposits then I can stop putting MMO in the fuel.

Greg, interesting your results. When I tried Sig Castor oil it managed to mix with the kerosene I was using. I have some lamp oil and will try that. I don't know what the difference is between the kerosene and the lamp oil. I have mixed fuel from both and haven't noticed any difference in the way the engine runs.


Back to the workshop for some more tinkerin' and thinkin'

cheers, Graham in Embrun near Ottawa Canada.