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robrike
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45 Posts
Discussion Starter · #1 ·
Hey Everyone.
My LB 10323 is still chugging right along. I have opened the main and pilot a size up each from original but still have surging on slow but fast is rock steady but smokes a little for the first 10 minutes or so. No problem there.

My only problem presently and I have not a clue why is the rpm's change if mowing with either side on an incline (mowing across a hill instead of up and down). If the left side is down and the right up, it slows down in speed noticeably but not enough to stall. If the right side is down and the left up it speeds up a bit above fast but not as much of a change in rpm's as when it slows. I have checked and rechecked float height and it all looks good.

This was happening before the jet enlarging and after. Reeds are new and I am tempted to change the float again (new one about 2 months ago) but it does not leak fuel down if I forget to close shut off fuel valve I installed.

Any suggestions on where to look? I am very perplexed by this? If it helps, the angles I am mowing are about 30 degrees or so. Parts guy says it is fuel flow pressure from gravity based on where the pickup is in tank (well the fuel hose nipple) and that may actually be it but I find that hard to believe because tank quantities do not change how it acts when mowing. It does this with a full tank or 3/8 of a tank.

Thanks everyone.

Rob
 

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Lawnboy fixer & user
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530 Posts
It's because of the air vane on the governor. On the Duraforce models, a tilt to the right (gravity) causes the governor vane to open the carb a little more. Just the oposite when tilted to the left, it slows down from gravity pushing the air vane a little bit more towards idle speed on the carb. My 22261 does the same thing when sidehilling on a ditch. An F engine will be less affected on a sidehill because of the air vane and engine position.

No way to prevent this that I know of. Except maybe a weightless airvane!
 

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robrike
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45 Posts
Discussion Starter · #3 ·
It's because of the air vane on the governor. On the Duraforce models, a tilt to the right (gravity) causes the governor vane to open the carb a little more. Just the oposite when tilted to the left, it slows down from gravity pushing the air vane a little bit more towards idle speed on the carb. My 22261 does the same thing when sidehilling on a ditch. An F engine will be less affected on a sidehill because of the air vane and engine position.

No way to prevent this that I know of. Except maybe a weightless airvane!
Thanks for the reply Al. That does make sense and my bank is pretty steep so I guess I will have to live with it. :banghead3 Does make me feel better to know it is fairly normal and has a logical explanation. I guess I have it dialed it pretty good then. RPM's when level are set at 3200 and idle drops it to about 2600 with some surge still. May open the pilot up another size this weekend.

Thanks again,
Rob
 

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OMC & Ariens lover!
Joined
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1,296 Posts
Hey Everyone.
My LB 10323 is still chugging right along. I have opened the main and pilot a size up each from original but still have surging on slow but fast is rock steady but smokes a little for the first 10 minutes or so. No problem there.

My only problem presently and I have not a clue why is the rpm's change if mowing with either side on an incline (mowing across a hill instead of up and down). If the left side is down and the right up, it slows down in speed noticeably but not enough to stall. If the right side is down and the left up it speeds up a bit above fast but not as much of a change in rpm's as when it slows. I have checked and rechecked float height and it all looks good.

This was happening before the jet enlarging and after. Reeds are new and I am tempted to change the float again (new one about 2 months ago) but it does not leak fuel down if I forget to close shut off fuel valve I installed.

Any suggestions on where to look? I am very perplexed by this? If it helps, the angles I am mowing are about 30 degrees or so. Parts guy says it is fuel flow pressure from gravity based on where the pickup is in tank (well the fuel hose nipple) and that may actually be it but I find that hard to believe because tank quantities do not change how it acts when mowing. It does this with a full tank or 3/8 of a tank.

Thanks everyone.

Rob
my 3002 C78 is the same way but thats a compleatly differnt govoner.i dont understand why mine does the same but a differnt motor...is it because the gas in the carb tilts to one side and may cause slight flooding?
 

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Administrator
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21,551 Posts
My duraforce is susceptible to wind changing engine speed. If the wind blows strong at the right angle it will increase the engine speed.
 

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robrike
Joined
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45 Posts
Discussion Starter · #6 ·
My duraforce is susceptible to wind changing engine speed. If the wind blows strong at the right angle it will increase the engine speed.
Man, that governor design stinks on these. I had always admired it before with faster speeds from flywheel pushing air vane closed to slow engine down. Seems simple and all but cannot really use a tighter spring or lighter vane without retooling stuff. I guess just live with it for me and maybe mow up and down the hill.

Now comes the question of the smoking for the first 10 minutes of operation since the main and pilot resizing. Guess that is normal and ok even though I am using Sthil HP Ultra which is full synthetic. I will say this, with the richer mixture it runs much cooler. I can hardly feel heat radiating from the top shroud when I shut down after mowing entire yard. Before it pumped out some heat. I will keep an eye on plug condition but I think any fouling during the first 10 minutes will burn off with the remainder of my run time to mow yard. Uses a little more fuel too but small price to pay for longer engine life. :thThumbsU

Thanks,
Rob
 

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5K Poster!!!!
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5,131 Posts
I have the same problem even with my F series engine mower, since we have really high winds in the spring and early summer down here in West Texas.
 

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robrike
Joined
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45 Posts
Discussion Starter · #8 ·
Well,
I decided that since my yard was caught up till the comiong weekend I would pull my carb off and recheck float height, etc. I had also ordered a new throttle disc after reading about surging in the ones that had the disc for the snow blowers and figured I would get one to have on hand in case mine was messed up. It was a whole $1.04 from my dealer after tax. :thThumbsU

I took it apart last night and measured my sizes on my jets since I had drilled them out a bit a month or so ago and this time I wrote down what size bit would fit and what would not. Pilot takes a 77 and main takes a 67 but nothing larger. I may have opened main up too much as it smokes some since my drilling last month. I have a new main on order.

What really shocked me though was my throttle disc was the small incorrect one. :fing20: I took side by side pictures with original on right and new replacement on left side. Mine is a 2000 model 10323 with the following info on the plate:
Lawn Boy
Model 10323
Sn- 200047441

Family: YL4XS.1415AB
Spec # - 98-1393
141cc


I was under the impression that this was really only applicable to 2003 and up but unless someone swapped carbs before I took possession this spring/summer then mine was hit from the factory too.

One concern I have is what the proper disc hole size will do to my jet adjustments I have made. My new main will be in in about a week and until then I could put the old disc back on if she just is not going to run with the proper disc and my jet mods. Anyone had luck with the correct throttle disc and enlarged jets or was it just too rich? I did adjust my float height a bit, it was set a little short of 1/2 if you were being really picky about it which seems to be what would lead to a rich condition if I have rationalized it correctly. I am assuming the higher up the float sits when carb is inverted the leaner it runs or perhaps I should say the less fuel will be in bowl for carb to draw from.

I was surprised too to find that running the bowl dry after mowing by closing fuel shutoff and running till it dies removes almost every drop in the bowl. I figured you would still have a puddle in the bottom but when I cracked my bowl open after removing carb I got maybe 3 drops of spillage. I will certainly be running it dry prior to winter storage even with stabilizer in it. I use Opti 2 which claims to have it in there already.

Just wanted to share my findings.
Thanks for all the guidance and help I have received here.

Rob
 

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