Chainsaw Repair
How To Basics - Carb Fixes + Mods - IPL and Service Manuals => How To Basics and Fixes => Topic started by: KilliansRedLeo on April 14, 2014, 03:14:37 pm
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Have been collecting some alternative fuels just to see.
I have e-free 91 octane pump gas mixed 50:1 with Husqvarna XP oil
Tru-Fuel 50:1 e-free
Husqvarna 50:1 e-free
Stihl MotoMix e-free 50:1
I am using a Husqvarna 365 Special w/MM to test. Saw has been running e-10 89 octane pump gas using Husqvarna XP oil @ 50:1.
What I am noticing is that there is a wide variance in carb adjustment necessary to get the saw running correctly. Saw was initially tuned on the e-10 fuel. Dumped the fuel and ran the saw until it used up the last of the fuel. Put in a quarter tank of Tru-Fuel, saw would barely run. Set the carb back to 1 turn each H/L saw would start and idle but no throttle response. Started opening jets a eighth turn until I got the thing running correctly ended up at L@1.5 and H@1.75.
Started over again using Husqvarna fuel, same process, Left the carb settings alone as were set at end of previous test, would not run just blubber. Went back to 1&1 H/L ended up at L@1 1/8 & H@7/8. I mean normally with a MM saw you have to go a little richer to compensate for the muffler mod, not leaner. Could there actually be that much difference in the fuel? You would think that if the saw were running well you could switch between fuels without that much messing around, otherwise how could they sell this stuff to the average Joe and expect no problems?
No time to do the Stihl MotoMix and e-free pump gas today but will report back tomorrow.
Anyone else seeing this kind of stuff or am I just out of it?
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I was using the 40 to 1 true fuel and went to 91 non ethanol mixed to 32 to 1 using stihl ultra oil.
I retuned a little but nothing dramatic. That is all I use now.
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Still don't understand why there are such a big variance in the tuning.
If you do a MM you need to open up the jets a tiny bit to compensate, this is not a fresh MM saw it has been running for about a year and a half.
So when I started the test I left the jets the way they were on e-10 50:1 assuming that the tune would be pretty close, no way, saw would not run worth a chit. So went back to factory specs of 1&1 and went from there. What really frosted me was when I switched to Husqvarna fuel 50:1 assuming again that I would be pretty close, no way. Went back to 1&1 and got completely different results.
I am really perplexed as to how things could vary so widely! The saw belongs to me but I still do not want to toast it trying to figure out what is going on! I do not believe the saw has some type of fuel delivery problem but I guess I will check it out just to eliminate that!
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You know when I was in California close to sea level and I switched from 91 ethanol pump gas over to the 40 to 1 true fuel I had similar problems with the saws idling correctly until I adjusted the jets.
Maybe it is the ethanol.
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Could very well be, Rochester New York is around 500ft above sea level. I am going to try the other two types of fuel I have tomorrow, so we will see. I know that non-e gas is a whole different situation in respect to tuning but I did not think it would be that much different from one brand to another.
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Started over from the beginning but was able to try all four fuel types. Still getting the same types of results. Tuning is all over the board. So, lets try this, if you had a Husqvarna 365 special with a MM and wanted to go with non ethanol pump 91 octane fuel and 50:1, where would you initially set your jets. Factory is 1&1 L&H. I am a pretty conservative guy so I started at 1.75&1.75 H&L.
I just can't understand how there could be that much difference in three different brands on pre mixed non-e canned fuel and non-e pump gas.
Beginning to believe that there is a problem elsewhere, going to pull the carb tomorrow and have a look.
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I would think the E-fuel would have the needles out the most for the air-fuel ratio on ethanol & methanol is close to 7:1
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OK, I'm at it again! Pulled the carb and pressure tested it for leaks, none. Put a kit in it and tested again, no leaks. Tested the saw for leaks, passed both pressure and vacuum tests. Decided to stay with the Tru-Fuel until I figured what was causing the wide variance, then try other fuels again. Anyway new plug, saw idles and starts, idles at 26-2700. L jet set @ 1.75 turns out. H jet the same for now. Saw will rev then when transferring to high revs 4 stroke heavily at WOT. Pulled the new Bosch plug for a look, gray! OH no, pulled the muffler no damage.
So what do the rest of think is going on? The Gray plug is bothering me a lot!
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Sounds like the high speed nozzle check valve is blown in the carburetor?
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OK, I will give that a look. I have a new carb on hand perhaps I will just switch carbs and see what happens.
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I remember when we first started using BelRay oil in the race bikes in the late 60s, it scared the chit out of us all because we were not getting nice 'MilkyWay' brown plugs. :o After much discussion with BelRay folks we found out that we would never get the color we were used to, they said that the synthetic stuff burned so much cleaner than the Torco T2 we were using that we would probably only get a medium tan/brown color plug.
That being said the gray still scares the hell out of me. With the E10/XP oil I was getting a nice brown color.
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OK, the saw appears to be running correctly, plug is still gray, but I have not put it in wood yet this time around. I have not been running it for more than a minute or so each test. So going to put it in wood and see if it blows up! L set @ 1 5/8 and H set @ 1 3/4! If it does not blow up and I get a decent looking plug, I'll drain the fuel and switch to Stihl Moto-Mix and see how it runs with the same carb settings.
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Well, I put it in wood. The saw did not blow up. Was idling at 2700 12500 WOT. Cut three cookies with it, ran pretty good. Took it into the shop pulled the plug.......pure white! Surely it must be an air leak to make it do this. Pulled the saw apart again and did another pressure/vacuum test. Started with 80KPa to 4.5 minutes to get to 60 Kpa. Did Vacuum test 60 Kpa close to two minutes to get to 50 Kpa.
Has got to be an air leak somewhere but can't find it, only things left to test are the carb spacer.
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Well, I put it in wood. The saw did not blow up. Was idling at 2700 12500 WOT. Cut three cookies with it, ran pretty good. Took it into the shop pulled the plug.......pure white! Surely it must be an air leak to make it do this. Pulled the saw apart again and did another pressure/vacuum test. Started with 80KPa to 4.5 minutes to get to 60 Kpa. Did Vacuum test 60 Kpa close to two minutes to get to 50 Kpa.
Has got to be an air leak somewhere but can't find it, only things left to test are the carb spacer.
That sure didn't show a air leak?
It didn't show a problem with the high speed nozzle check valve either.
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If the saw is 4 stroking at wide open throttle and you hear it clean up when put into wood I would not sweat it.
It would not bother me if the plug was green as long as I hear a good 4 stroking.
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I don't look at spark plugs that much. Maybe if the chainsaw will not start? Or if I'm tearing it down for some reason. I might look at te numbers of the plug on a strange chainsaw?
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LOL
I just changed premix oil just a few months back and I was worried about the carb settings myself on all my saws I couldn't get one saw to run right thinking it was a oil problem then I changed my fuel and impulse line and everything was a oh k ;D
I had a **** fuel line on a 60 cc saw
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maybe something to concider...
trufuel and motomix seem to be made by the same company in shreveport, la. never used either, myself. are they the same thing?
running the winter-blend gas we got up here, on a 80 degree day like we had on monday may change things a bit?
read somewhere a while back, that winter blend unleaded supposedly adds butane as an ingredient, for quicker starts.
-joe
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Sounds like the high speed nozzle check valve is blown in the carburetor?
Sir James Winningham WINNS! Jim send me your address, I will send you a saw to play around with!
I dug around and found a new carb, switched carbs, everything is as it should be. Will put B/C on it in the AM and see what happens. Did not take the carb apart, was so pizzed off, just changed the carb and gave it a shot. If it runs well in the AM, I'll start trying the other brands of fuel.
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I must have missed something. Was the saw not running right.
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It was running right on e-10 and 50:1. I decided to run a test with four different types of alternative fuels, from tru-fuel, Stihl, Husqvarna and non-e pump gas. When I began the tests, the brand of fuel made huge differences in the tuning of the saw.
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Oils effect saw tuning also.
Some synthetics do not contribute to combustion and to go from Pennzoil air cooled at 32:1 to say like Red Line at 32:1, your saw will suddenly be noticeably lean.
Cut4fun and I swap saws sometimes and he uses Klotz at 32:1 and this always requires a re-tune because I run Pennzoil.
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I do not get it. If the high speed nozzle check valve is defective would it not have the same affect on all the different types of fuels. Just trying to understand in case I ever run into something like this myself.
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My original intent was to try some alternative fuels, and I was getting what I consider wide differences in tuning between brands, as much as half a turn form one type to another. I was using a saw that I own, that had not been run in a few months. I don't get why it would not affect the tuning so widely either.
I thought that there would be minor differences but nothing like I was getting earlier. It was late in the day when I switched out the carb, so I will run the tests from the beginning again tomorrow!
I have not torn the carb apart yet but my bet is that the check valve IS or went bad while I was messing with the saw. I just put on a new carb and set it at 1&1, started right up and would idle. Will set the H side in the AM and put it in wood. Still concerned about plug color but we will see.