My Tractor Forum banner

1 - 8 of 8 Posts

·
Registered
Joined
·
26 Posts
Discussion Starter #1
Hi Guys,

I was gifted a 1999 10323 Lawn Boy recently. The owner said he'd bought it as an NOS unit about three years ago in the fall. He put it together two years ago but he said it always surged and just "didn't run right". He let it set over the winter with gas in it and then the next spring it wouldn't start so it's just been setting since then as he bought a different mower.

I needed a mower and didn't want to mess around so I wanted to order a new carburetor but alas they don't sell assembled ones any more. I opted for the 107-4607 carb kit that conains all the pieces including the carb body. I also ordered the .425mm pilot jet to replace the original one with.

I got it assembled and switched the carbs just a bit ago and it started up after a few pulls (the rubber on the primer button is deteriorated so I couldn't prime it). I let it run for 20 mins to get it warmed up and it had a slight surge and it seemed to "cackle" a bit . . . it went hum, slight drop in rpm & cackle, speed up, hum, slight drop, etc.. I pulled the main jet out of the original carb and enlarged it with a #67 drill bit and then installed that in the new carb. Now the surge seems to be gone but it seems to be a near constant cackle. It's not bad and it maintains rpm but it's just not a steady hum. I let it warm up half an hour and even cut a couple swaths in some pretty deep grass with it and it chugged right through it, barely dropped rpm 8->. It didn't seem to cackle as much when it was under load but it did smoke a fair bit.

It's not a big deal, I can live with it as it does cut grass and it maintans a good rpm but it just doesn't seem right . . . am I missing something or do they just run this way (sure doesn't sound like my old Hodaka Super Rat 100 MX two stroke dirt bike of years ago . . . of course it had a much larger expansion chamber on it . . .).

Any tips, suggestion, etc. would be most welcome!

Thanks!

Steve
 

·
Registered
Joined
·
26 Posts
Discussion Starter #2
OK, I dug up some fuel line so I installed a 90 degree fuel shut off valve and an inline B&S filter this afternoon.

Just playing around I turned the fuel off and ran the carburetor dry . . . towards the end it suddenly picked up just a little rpm and it ran smooth as glass for a few seconds before it died. I did this a couple more times and it acted the same each time.

Hmmmm, do I have the float level too high? I didn't adjust it as it looked to be at 1/2" when I assembled it, but I'm telling ya it ran smooth as glass as it was running out of gas - i.e. when the fuel drops in the fuel bowl it decides to run right so that kinda nudges me towards adjusting the float to drop the fuel level in the carb a bit.

Am I on the right path?

Thanks!

Steve
 

·
Registered
Joined
·
26 Posts
Discussion Starter #4
I just took the carb off again (I'm becoming a pit crew for this! The fuel shut off valve makes the job much nicer!), the float height is spot on at 1/2".

I'm wondering, should I try the original pilot jet? I never ran it stock, the original owner said it surged and "never ran quite right" so when I put the new carb on I just put a larger pilot in.

At first I put a larger pilot in and left the stock main, later I reamed the old main and installed it, so now it's got a larger pilot and larger main. Maybe backing up to stock isn't a bad idea?

Hmmmm, I got an hour to play . . . back in a bit!

Steve
 

·
Registered
Joined
·
26 Posts
Discussion Starter #5
OK, I installed the stock pilot jet since it was easy and it made a HUGE improvement! 8->

So I bit the bullet and pulled it apart AGAIN and switched the main back to the stock one. Another good improvement! 8->

It pretty much hums right along now with just an occasional hiccup and that I can live with.

I wonder if the surging problem isn't due to these plastic carbs aging and developing a slight air leak somewhere and the richer jets just compensating for that? I'm just curious because the previous owner said it had developed a surge towards the end of the last mowing season he used it. Since the original carb worked and then developed a surge and now with a brand new carb on it the surge is gone again it makes one believe aging does something to lean out the carbs.

Whatever, I can get the lawn mowed now! I'll keep the larger jets handy though . . .

/Steve
 

·
Registered
Joined
·
26 Posts
Discussion Starter #6
I mowed with it today. The lawn had gotten tall as my wife had shelled the other mower and I was still working on this one. All I can say is WOW! THAT THING CAN MOW!!! The old four stroke wouldda been bogging and dieing, but this thing just hunkered down, maybe smoked a tad, and spit out grass! :)

It purred like kitten the whole time! I'm thoroughly impressed with the thing!

It's set up for side discharge right now, but I gotta find a mulch plate or bagger for it - the darn thing will spit grass from here to kingdom come!

Take care all,

Steve
 

·
Registered
Joined
·
2,350 Posts
Glad you got it running good. I know my good old Duraforce is just the best mower! I have used the snot out of it and mowed some grass that was so thick and tall I couldn't believe it cut through it, and like you said it just hunkers down and pulls through. You would be hard pressed to bog down one of these mowers!
 
1 - 8 of 8 Posts
Top