Lawn Boy 7351 Carburetor Help

I have my old Lawn Boy 7351, Model Year 1986 (Beginning Serial #E00000001 & Ending Serial #E99999999) that is running poorly. It's hard to start and once running, is almost impossible to restart.

Some time back I found a rebuild kit for the carburetor. That year should be a 684352 Carburetor Assembly, which replaced part number 683632. Apparently this is a Walbro LMR?

Kits I'm finding now, such as this one from Wal-Mart Walbro K11-LMR Carburetor Repair Kit for LMR Carburetors, do not seem to contain gaskets, diaphragms or reed/pumps. Now, it's been a while since I last had this apart, but it DOES have diaphragms, gaskets, reed/pump, etc. that I'm not seeing in this type of kit, right? This seems to be about the only kit available for this carb.

The other thought is a replacement, after-market carb. I'm NOT paying $180-200 for an OEM carb! However, I don't seem to be finding this carb with a replacement. If anyone has any ideas about that, I'd appreciate it.

Thanks!

John

The 684352 carb does not have any diaphragms or Reed pumps. It is a float type carburetor. To rebuild it, you will need a K11-LMR rebuild kit and a new float (part number 75-570 if I remember correctly.)

primerbulb120 said:

The 684352 carb does not have any diaphragms or Reed pumps. It is a float type carburetor. To rebuild it, you will need a K11-LMR rebuild kit and a new float (part number 75-570 if I remember correctly.)

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Good Afternoon Primerbul120,

Thanks for the reply and you are absolutely correct! I went ahead and decided to pull this thing apart. I had just been working on my Stihl 025 and had that carb type in mind. It had been awhile since I had the Lawn Boy Carb apart the last time, so I was SURE it would resemble the Stihl! As you stated, the kit is a K11-LMR, contains:


and those are the parts I've found.

Rebuild kit is ordered and on the way, so that mower will be benched for a few days. Soooooo . . . . do I NEED to replace the float if it looks to be in good condition? No recall as to whether I replaced it with last rebuild, or not.

Thanks again!

John

I'd go ahead and replace the float while you have it apart. That way there's less chance it will fail and put the mower out of service again. :thumbsup:

Thanks for the help and the parts numbers Primerbul120. Looks like you were spot on with your numbers. Ordering parts from walmart.com. I find the 75-570 andthen found 75-570-01 on ereplacement.com when I Googled Walbro LMR-1. Probably the same thing. Funny thing, Wal-Mart On-Line has both parts; 75-570 for $10.17 and the 75-570-01 for . . . oh, that is weird! It was $6.95, went up to $7.75. Computers are wonderful! Anyway, ordered that too. :thumbsup:

John

Use Ebay when you buy parts next. You can get them quite a bit cheaper there!

primerbulb120 said:

Use Ebay when you buy parts next. You can get them quite a bit cheaper there!

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Wal-Mart is trying to compete with Amazon and has an amazing variety. Those prices I was looking at? Free shipping. Turns out I could have saved a dollar on the float; about the same on the rebuild kit.

Got the carburetor cleaned out nicely and new parts installed. Interestingly, I did not find a needle valve seat in it when I took it apart. Got that replaced and seated. The one thing I did not mess with was the Welch Plug, which I guess would let me pull out the throttle shaft assembly? Any thoughts on that?

The other thing I did, was possibly get a little big for my britches and decided this needed an in-line fuel filter. There was no sintered filter in the fuel inlet and no sleeve around the jet housing. Didn't want crud running straight into my clean carb. Started pretty good and ran pretty good. Got the altitude needle valve adjusted. Started off mowing and then it started pooping out when I would go up hill. Would run it I pushed it up to 'Choke', which told me it was not getting enough fuel. Finally decided that, after doing a little research, that the extra fuel line I added and the filter was probably overwhelming the gravity feed.

Now I'm trying 'Plan 2'. I had the in-line filter pictured below.



The sintered filter in it greatly resembled what I saw someone pull out of the inlet in a Walbro Carb rebuild. Cut the filter apart and extracted the filter assembly. Nope, too big for the inlet. It did, however, nicely fit into the fuel line. Pushed it up the fuel line for a few inches and will give that a shot. I'm looking for one of the 'filter' sleeves that goes over the main jet housing in the meantime. I'll test this out later and see if hills still cause a problem.

John

JayTee said:

View attachment 33850

The sintered filter in it greatly resembled what I saw someone pull out of the inlet in a Walbro Carb rebuild. Cut the filter apart and extracted the filter assembly. Nope, too big for the inlet. It did, however, nicely fit into the fuel line. Pushed it up the fuel line for a few inches and will give that a shot. I'm looking for one of the 'filter' sleeves that goes over the main jet housing in the meantime. I'll test this out later and see if hills still cause a problem.

John

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I found one of the little sleeve filters on eBay and it will be coming my way sometime. In the meantime, 'Plan 2' seems to be working well. Have the little sintered filter in the line, which now conforms to the original length, instead of being 3 or 4 times as long (to accommodate the filter/housing and 90 degree turn from the tank to the carb). Didn't run the mower around the house and on the hill again, however, I ran it and tipped it up on the back wheels to simulate a hill and it ran without problem. May leave that in until next carb overhaul.

Is removing that Welch Plug in the bowl something necessary to do when overhauling one of these, or an option?

John

Although these Walbro's are on Briggs engines, this may help ..??

http://outdoorpowerinfo.com/repairs/#id_walbro

Boobala said:

Although these Walbro's are on Briggs engines, this may help ..??

http://outdoorpowerinfo.com/repairs/#id_walbro

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Thanks for the link Boobala. Lot's of good information there, I've bookmarked it. Wish I could find a site like that for the LMR carburetor.

John