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O'Donnell fuel produces less smoke

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bigdawg2

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Columbus, Ohio
RC Driving Style
  1. Bashing
  2. Racing
I just switched from using Blue Thunder 20% to O'Donnell 20%. I returned the card to factory settings (I'm pretty sure) but there is little to any smoke from the exhaust. I didnt try re-tuning again because I didnt want to dammage my newly ported and polished S-25 engine by running it to lean. I know its running super rich cause when I spit on the head it dosent do anything (I dont have a temp gun). Does this fuel just produce less smoke or should I lean it some to get it hotter, then the smoke will come. Thanks for any help
 
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It should smoke like hell at factory settings. Did you drive 'er around at all? It may not blow smoke until you get it moving/ rpm's up a little.
 
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Sounds like it's not getting hot enough to vaporize the oil.
Do you see oil dripping out the stinger or the exhaust port?
Given your info about resetting the HSN and the temp (lol), you need to lean it out a bit.
To be on the safe side go to the happy medium - reset your HSN to a point the reflects 1/2 of the difference between where you had it running on the Blue Thunder and the current setting. For example, if you took off 1/2 a turn to get to your current setting, dial in a 1/4 turn and run it enough to warm it up before checking the temp.

It's been a long time since I ran Blue Thunder, but I don't recall there being a huge difference between the setting for BT & O'Donnell. I'm guessing that your final setting with the O will be pretty close to BT's.
While you really should get yourself a temp gauge/temp gun (I'm sure you already know that) like the DuraTrax FlashPoint or OFNA's Temp Gauge etc.
Personally I would avoid the on board models that loop a wire around the cooling head - for starters you need one per vehicle...

The old spit gauge worked like this for me.
1. Spit or drop of water just sits there - too cold - lean it out.
2. Spit or drop of water vaporizes instantly - way too hot - richen it pronto at least an 1/8th of a turn - maybe even shut it down to cool off before continuing...
3. Spit or drop of water boils off in one two seconds - about right.
 
Hmmmm I would get temp gauge it helps alot. And far fuel
goes I found my truck to be a dog when using 20 . Another
user recomended 30 10-13 and the truck never ran better. And I get smoke on take off and she wheelies like nuts.
 
I was forced to run odonnels over the byrons I usually run (LHS didn't have byrons) and I noticed that it's far more oily than many fuels I've run in the past. Had to lean it out a good bit to get it to run right. Excess oil will drop your temps below the smoke point maybe...

Really though, you should get a temp gun. They can be had for around $20 and will really help you become a better tuner in general.
 
Remember that Blue Thunder is a good break-in fuel for a reason. It has A LOT of oil in it. You shouldn't have needed much re-tuning of your mill when you switched.

Since you did go back to factory specs it SHOULD be running rich. The spit test confirms this (although a temp sensor unit is almost as important as a fail-safe for nitro) so you might want to start leaning the tune for power if you are sure the mill is properly broken-in.
 
For future reference, don't reset the needles for any reason other than a big problem. If it was running fine before, there was absolutely no reason to make drastic changes to the needles for a fuel brand change. "Never tune an engine unless it's warm". You hear this over and over for a reason. You probably would have only needed less than an 1/8 turn either way to get it where it needed to be. Would have been no different than tuning for different weather conditions. Once it's close or right, it doesn't take much to keep it there.
 
The O'Donnell's is superior to the B.T. in every way. Lean her out, she'll smoke. Most modded engines are more efficient, thus requiring leaner needle settings. Unless you get a drag mod, then you may need to run richer settings. That engine will run 8 gallons @300F, I did the same thing you did. I wish I had just bought a better engine with that 100 dollar bill.
+1 to the above, when you switch fuels just richen it up 1/4 turn on both needles and go from there. Factory settings are generally too rich period, even for breakin. The RTR engine manufactuers do this so the fuel will flush out any trash the engine may have left over in it from the machining process.
Your higher end mills are usually right on out of the box though.
 
Cool, thanks for all the helps everybody. The only reason i reset the needles back to factory was because after doing the engine modding they say that u should do a quick re-break in. But it never told me what settings to use. One more thing I learned i guess. I got it start a lil yesterday but it would not stay on. I tried adjusting the LSN by 1/8 turns it didnt help. Then tried the same with the HSN, didnt help. I made sure the gap was correct with the idler gear (2mm). I'm pretty sure I can get it started, just have to play with the settings some more, but by this time the roto start battery died. I think I'm going to switch to pull start. I'll give it another try today and keep u guys posted.
 
I'd hold off on the pull start until you get it running reliably. If it won't start by cranking it with the roto, it definitely won't start with short, quick spins. Make sure the glow plug is still good and lean 'er out until it'll idle and stay running.
 
Get rid of O'donnalds Fuel Fast, That stuff sucks, Ill run Traxxas Fuel before I used O'Donnalds Again.
 
Bigdawg - For the most part 99% of your adjustments involve the HSN and you should hardly ever need to touch the LSN. You only need to toy with the LSN once the engine is running. For example if it bogs early in the acceleration curve.
Here's how I would try to get this engine running...
Reset the LSN to what it was before you touched it.
As concerns the HSN, try setting it to something like 3 1/4 to 3 /2 turns out (lightly screw it in until it stops and then unscrew it 3 1/4 to 3 1/2 turns).
Metalhead Matt's advice is right on the money - If it won't start by cranking it with the roto, it definitely won't start with a pull start.
Recharge the roto - recharge the glow plug igniter - put in a new glowplug and then try to start it.
BTW - Have you gotten a temp gun yet?
 
Finally got it started and running good. I had to richen the LSN due to the needle being a lil off. ( I think the threads that allow u to screw it in and out are worn out. So it was really hard to set it 3 turns out). Once running temp got to about 190F (yes I finally got a temp gun...lol) so I leaned it on the LSN till i got a nice take off and temp got to 235F. The smoke also finally came, I had a nice trail. I leaned the HSN some and the top end came to life. Temps peaked at about 270F-280F, I think thats ok for this motor. Its good to be done, I can finally put the body on it and enjoy the truck. Thanks everybody for all the helps, u guys are great. .... Also I think I will hold off on the pull start. Once the settings where right, I took a 2 hr break came back and it started up with the first spin of the roto.
 

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