E15 experiment

Geo-TH,In · Aug 12, 2014

I purchased my 2004 terramite used when it had 430
hours on it. The left spark plug was completely
carboned up. I cleaned carb, new air filter,
helped a little, but still a carbon problem and a
dieseling when engine was hot after working hard.
Engine would ran backward. I concluded there had
to be pre-ingniton, pinning. Engine doesn't use
oil, very good compression, 1500 hours on it. Good
running engine.

There are no fuel adjustments on carb. If you can
find any, post pic. I've looked, nothing at all.

That's when I decided the only way to lean out
fuel mix was with E15. I made my own using E85 and
93 octane.

After 5 hours, I pulled the plugs. There appeared
to be a white ash on plug. Like the white ash you
get burning charcoal, carbon. There also appears
to be places on the top of piston where the carbon
layer is burning off. Piston looks good. No
pitting.

I posted pics of the old and new plugs. New plugs
have 10 hours on the.

I think I'll see what happens on the next 5
gallons before I change E ratting. I really don't
care about the fuel pump, if it's damaged it won't
cost that much. Worst case, Engine is only about
$1500.

The camera doesn't show the results as well as in person. Look at the very end of plug near the threads. Very black on the right plugs. Not so black on the left plugs.

Tom Railsback · Aug 12, 2014

Get rid of the Champions and get autolite or AC Delco plugs.

Geo-TH,In · Aug 12, 2014

Champion is what Kohler calls for. I don't think my dieseling and carbon is related to the plugs as long as I use the heat range Kohler is asking for, do you?

GregCO · Aug 12, 2014

I have a 25 hp kohler in a garden tractor and that thing will foul plugs and diesel and then bend push rods when I shut it off as well if I don't run high octane fuel in it. Pain in the rear for sure. You are right, those little Nikki carbs don't have an adjustable main metering jet and they seem to be a little rich all the time. Adding a little E85 to bump up the octane and lean out the mix seems to work for me as well. So far the plugs stay cleaner and no dieseling and I don't have to change push rods anymore. I add E85 at about 20%. seems to do the trick. If I was smart enough to figure out the right jet size I would just run straight E85 and be done with mixing fuel.

Greg

Vern · Aug 12, 2014

If your tractor has a fuel shut off solenoid then open the throttle when you turn off the ignition.

Vern

T in NE · Aug 13, 2014

Possibly not, but the plugs sure would last longer. I had a Dakota that burned oil and would eat Champions for breakfast. Literally. Drive it to the barn (mile trip) in the morning and replace plugs to go home for breakfast. Not a problem with autolites.

Geo-TH,In · Aug 13, 2014

I tried running the next hotter plug. The tips would run clean, however, it would still diesel, piston carbon up. Only solved plug problem, not the one I'm really after.

Geo-TH,In · Aug 13, 2014

Greg,
Good to hear there is another person who likes to experiment with E85. My early results look promising. I was planning to push my experiment past E15. Just doing it in babby steps. What octane do you use?

I didn't know running an engine backwards bent push rods, but it sound possible. That's good to know too.

I removed the mag kill wire from switch. The gas solenoid shuts gas off to engine. At an idle, the engine shuts off in about 5 seconds. Sometimes, I like to shut it off with the kill wire to see if it engine will diesel, which it doesn't. So increasing octane and ethanol must be helping cooling things off.
George

GregCO · Aug 14, 2014

George, along the front range of CO our regular unleaded fuel is only 85 and premium is 91 so the E85 at 111 (i think) is a good way to bump octane without buying expensive additives or going to the track to buy racing fuel. I just use the 85 octane fuel and add E85 to it. The fact the the Kohler's are rich to start with the alcohol does lean the fuel out and the increases octane enough to find a good middle of the road. So far here no noticeable damage and it runs really nice.
I didn't think about using the fuel solenoid to shut it down instead of the ground to the mag. Good idea. At least it will lean out and then quit and not keep trying to burn the unburnt fuel and residues in the combustion chamber. I'm going to give that a try myself. Thanks for the idea.
Greg

Bob · Aug 14, 2014

A question for you, Greg... What elevated octane value do you perceive that your Kohlers need?

And WHY?

oldtanker · Aug 15, 2014

George, Campion isn't well know for high quality plugs like they once were and haven't been in some time. I had an air cooled twin that had Campion's in it when I bought it. I'd get less than 25 hours on a set of plugs. I rebuilt the engine, bored, pistons the whole bit. Still less than 25 on Champs. Switched brands and would run close to 80 hours before it gave me problems.

Now you want to run Champs cause Kohler recommends them. Yet Kohler says not to run any ethanol if possible in most of their engines. They recommend 91 octane last time I looked.

Rick

GregCO · Aug 15, 2014

Hi, Bob, When I first bought this machine from day one I was experiencing problems with dieseling at shutdown as well as pre-ignition at start up when it was hot. It would rattle and kick back hard on a hot start. First thing I thought was there was a timing issue going on so I took it back to the Deere dealer to have it checked out. When I picked it back up they said they didn't find anything wrong with timing or fuel delivery, but did caution me on not running at least 91 octane in it. I found it hard to believe that an industrial engine needed that kind of fuel especially at high altitude. Most engines loose their need for high octane fuel as the altitude goes up and we are pretty high.

Anyway, I played around with this thing and found that if I ran 85 or 87 in it I would continue to have issues with shutdown and hot starts and bent push rods because of the dieseling problem. If I ran 91 things were fine.

So, I guess my answer to your question is from my experience it needs somewhere in the neighborhood of 90 to stop damaging things and run right.

Why? I got really tired of replacing push rods as it was bending one every couple of weeks in the summer during mowing season. At first I thought it was just a tight valve guide binding them up, but it was never the same one twice in a row. It has bent every one of them multiple times at one time or another and only when I was running anything less than 91 for fuel.

So, since everything else on the place runs fine on 85 including our vehicles I keep a little E85 around just to doctor the gas that goes into this machine. So far the alcohol has not caused any issues that I can find. I did finally have to rebuild the carb this spring as the accelerator pump split and an O ring cracked, but it is 10 years old now and was probably due anyway at 510 hours running time.

Greg

oldtanker · Aug 15, 2014

(quoted from post at 19:43:17 08/15/14) Hi, Bob, When I first bought this machine from day one I was experiencing problems with dieseling at shutdown as well as pre-ignition at start up when it was hot. It would rattle and kick back hard on a hot start. First thing I thought was there was a timing issue going on so I took it back to the Deere dealer to have it checked out. When I picked it back up they said they didn't find anything wrong with timing or fuel delivery, but did caution me on not running at least 91 octane in it. I found it hard to believe that an industrial engine needed that kind of fuel especially at high altitude. Most engines loose their need for high octane fuel as the altitude goes up and we are pretty high.

Anyway, I played around with this thing and found that if I ran 85 or 87 in it I would continue to have issues with shutdown and hot starts and bent push rods because of the dieseling problem. If I ran 91 things were fine.

So, I guess my answer to your question is from my experience it needs somewhere in the neighborhood of 90 to stop damaging things and run right.

Why? I got really tired of replacing push rods as it was bending one every couple of weeks in the summer during mowing season. At first I thought it was just a tight valve guide binding them up, but it was never the same one twice in a row. It has bent every one of them multiple times at one time or another and only when I was running anything less than 91 for fuel.

So, since everything else on the place runs fine on 85 including our vehicles I keep a little E85 around just to doctor the gas that goes into this machine. So far the alcohol has not caused any issues that I can find. I did finally have to rebuild the carb this spring as the accelerator pump split and an O ring cracked, but it is 10 years old now and was probably due anyway at 510 hours running time.

Greg

So you run the recommended plugs and cheap gas instead of what they recommend? Then wonder why you have problems? Then add ethanol against their recommendations? Whatever floats yer boat I guess. I refuse to run ethanol in anything I can avoid legally.

Rick

GregCO · Aug 17, 2014

Well Rick in CO you can buy fuel with ethanol or fuel with more ethanol. We cannot buy fuel without it. So we make the best of a bad situation. As far as plugs go I have tried to replace the plugs with other brands and for whatever reason the parts house cannot cross them to another brand. I know, seems odd, but that is what I have found. The replacements that I have found that are other brands are too long and may contact the piston so I don't try them. Fuel is fuel as long as the mixtures can be met. The reason Kohler does not recommend ethanol is because they have not upgraded their rubber and plastic components to accept it. Other than that any engine will run on it as long as the proper air/fuel mixtures can be met to keep them from running too lean. It takes about 20% more alcohol to run an engine on alcohol than gasoline. As long as we don't let them lean out they should be fine. Since the Kohlers are WAY to rich from the factory at high altitude and the manufacture are not willing to re-jet to compensate or even offer a fix we can get away with a little added ethanol in the fuel with no issues. Believe me the next machine I buy will have a Honda, Kawasaki, or a Yamaha in it. The US made small engines are crap and wont run right, right out of the box.

Greg

E15 experiment

Geo-TH,In

Well-known Member

Tom Railsback

Member

Geo-TH,In

Well-known Member

GregCO

Member

Vern

Member

T in NE

Well-known Member

Geo-TH,In

Well-known Member

Geo-TH,In

Well-known Member

GregCO

Member

Bob

Well-known Member

oldtanker

Well-known Member

GregCO

Member

oldtanker

Well-known Member

GregCO

Member

Similar threads