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Discussion Starter · #1 ·
Hello all......it has been a while since I last visited or posted.

Last year my Lawn Boy 10550 started the ole suging thing. Today, I finally got around to starting it since last fall. Mower started right up but the motor was surging. Ok, no biggy....I remove the carb. and it was SPOTLESS! I disassembeled it, cleaned and blew air through it. Re-assembled and burruummm....and the surge is still there. What's going on?
Thanks.
 

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2 stroke enthusiast
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Did you remove the pilot jet from the side and clean it? If so, then you should try a #40 jet. If that doesn't clear it up, most of have done well(including myself) with running the 42.5 pilot jet along with a very slight opening of the main jet using a #68 micro drill bit. I have a 324 that wouldn't cooperate at all until I did this. Now, it runs very smooth and even, both at low and high speed.
 

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Discussion Starter · #3 ·
This model, 10550 with the DuraForce 6.5 has the plastic body carb. I don't believe it has a pilot jet. I do remember, my commercial mower had the alum. body carb. and that did have a pilot jet on the side of the carb.
 

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Also if you look at the throttle plate there is a round opening, some are about the size of a 3/32 or so drill bit and some are very small like this big -> . The VERY small ones were put in by accident at the factory-apparently they are from the R-Tek snow blowers and were/are a contributor to the surging.

Only model numbers in the 23000+ to like 24 or 25000 had the surging there is a big thread on this if you search "surging cure".

1. If you want to do the throttle plate its like $2 and then try the Suzuki 40.0 pilot jet which should cure all surging with the bigger opening throttle plate.

2. If you keep the small opening throttle plate-do like Echo said and use the R-Tek 42.5 pilot and wire drill bit #68 the main jet.

I have done both with good success.
 

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This model, 10550 with the DuraForce 6.5 has the plastic body carb. I don't believe it has a pilot jet. I do remember, my commercial mower had the alum. body carb. and that did have a pilot jet on the side of the carb.
The pilot is under the sticker on the left hand side of the carb (from the top). it screws out with a regular (std) screw driver.
 

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2 strokes forever!
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New Suzuki #40 pilot jet cured my 10550's surging. Did this within the 1st week I bought it and it has run flawlessly since! I also took the carb off, disassembled everything, and cleaned all the parts properly. Do it. :thThumbsU
 

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The Sea of Green Machines
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No matter what you do, there are certain atmospheric conditions that will cause surging. I wouldnt get to obsessed with it, especially if it only does it cold.
 

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Lifetime Lawn Guy
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What fuel mix are you running? Mine (10525 DF) runs smooth and only surges a few times at cold start with LB 32:1 mix, but with Opti-2 100:1 (that I run in all of my other 2 stroke handheld equipment) it surges most of the time unless it's under a pretty good load (mowing heavier grass). I just try to fill it at home out of my 32:1 LB can and it seems to be happy. The Opti-2 I've ran in other LB's and they ran fine on it. Just the DF acts funny.
 

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Discussion Starter · #10 ·
Thanks everyone for the replies.
Now, I am going to sound real dumb here. ARE YOU KIDDING ME, THE PILOT JET IS BEHIND THE DECAL?? I installed a new deck, shortblock, all new wheels, disassembled the gearbox & packed it with new grease and cleaned the carb., several times and you are telling me there is a pilot jet behind the decal. GEEEZ...I never pulled that decal off, I thought this (Plastic) model carb lacked a removable pilot jet.

OK, what ratio am I using? 40:1 with Klotz 2 cyle oil. I love the smell!

Now, who can supply a # 40 Suzuki jet?

Thank You!
 

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Discussion Starter · #11 ·
Yup...sure is..I pulled the decal off and there is the pilot jet. Pilot jet # 37.5. I totally rebuilt this mower and it looks like new but it never ran great, ran good but had a surge.
 

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Did you remove the pilot jet from the side and clean it? If so, then you should try a #40 jet. If that doesn't clear it up, most of have done well(including myself) with running the 42.5 pilot jet along with a very slight opening of the main jet using a #68 micro drill bit. I have a 324 that wouldn't cooperate at all until I did this. Now, it runs very smooth and even, both at low and high speed.
Im having the same issue as the original post. Can anyone tell me if this drill bit set will have the #68 bit that I need? Any suggestions appreciated. I suspect that the only reason I would buy this set is for that particular bit, I doubt I will use any of the other bits. In other words, I dont want to spend 50-100 bucks on a set of wire bits that I wont use. Thanks. Oh, and I have the 42.5 briggs pilot jet already, have not installed it yet.

http://www.amazon.com/20-Pc-Wire-Ga...f=sr_1_11?ie=UTF8&s=hi&qid=1284065634&sr=8-11
 

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Since the pilot jet is so easy to remove, try cleaning it out REALLY good. Use a small wire and solvent to get it as clean as possible. Easy to try while you're waiting for your new jets.
 

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Discussion Starter · #14 ·
The wire on my wire brush is a perfect fit to clean the pilot jet. However, I still want to change it to a # 40 Suzuki jet. Who is a relaible supplier for this jet?
Thanks
 

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I too am interested in this. As my grandpas DF has this issue. Thanks
 

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Im having the same issue as the original post. Can anyone tell me if this drill bit set will have the #68 bit that I need? Any suggestions appreciated. I suspect that the only reason I would buy this set is for that particular bit, I doubt I will use any of the other bits. In other words, I dont want to spend 50-100 bucks on a set of wire bits that I wont use. Thanks. Oh, and I have the 42.5 briggs pilot jet already, have not installed it yet.

http://www.amazon.com/20-Pc-Wire-Ga...f=sr_1_11?ie=UTF8&s=hi&qid=1284065634&sr=8-11
Looks like it has what you need 1lawnboy. I buy Briggs jets as they are half the price as Suzuki branded parts. In the past, Suzuki #40's cost be about $8each whereas the 42.5 Briggs are about $4.
 

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Looks like it has what you need 1lawnboy. I buy Briggs jets as they are half the price as Suzuki branded parts. In the past, Suzuki #40's cost be about $8each whereas the 42.5 Briggs are about $4.
Ok, I guess Ill order the bits. The pilot jet I ordered was a B&S (801308), it was 4.75 at my local dealer. I actually ordered 2 because I figure Ill come across another one eventually.
 

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Discussion Starter · #19 ·
Ok, I guess Ill order the bits. The pilot jet I ordered was a B&S (801308), it was 4.75 at my local dealer. I actually ordered 2 because I figure Ill come across another one eventually.
Thanks for the part number, I just ordered 2 from SEPW
 

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I just swapped the jets out and the surging subsided quite abit. The bad news it that I thought this was going to be the only problem to fix. Lets take this back a little further. I put my 10547 back in the shed after mowing with it a couple of weeks ago. It ran great at that time. I got it back out last week and it wouldnt start, I pulled and pulled. Decided to steal a coil from a donor Dura easy stride, then it started. The 10547 fired right up, but the throttle control was erratic and the surging. Since then, I swapped the pilot jet and carb. It runs with the choke on, but if I take the choke off, it really slows down to a humm. I can then take the throttle up to choke and bring it slightly down to fast and it runs ok until I hit the grass, then it slows back down. Anyone have any ideas? Unfortunately, Im thinking it may be an oil seal, but the crank doesnt look wet. Maybe its the top seal, a carb gasket? Any thing you suggest to look at? Let me know.
Thanks,
1lawnboy
 
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