# Sears 51.7cc "Brushwacker"...questions



## wrencher2b (Feb 19, 2005)

Hi all:

I'm trying to resurrect a Sears 51.7cc "BrushWacker" (636.796243) and am undertaking a search for the necessary replacement parts(mostly fuel related).

Sears wants more than they deserve for the few parts that they carry for this 10+ year-old machine. So, I'd like to go to the actual manufacturer or its' parts distributor to possibly get a better selection and, hopefully, much better pricing.

The BrushWacker has "TK-9H A1" carburetor. Judging from the Sears.com parts illustration of the carburetor diaphrams and comparing them with those shown on jackssmallengines.com, the engine is a Kawasaki. Other than that I don't have much information.

Can anyone help shed some light on just who the manufacturer of this equipment is??

Thanks for help or direction that you can provide.


----------



## bugman (Aug 12, 2004)

well if its sears, most of their stuff is ayp made but the carb and all engine related stuff should go to sears or the engine maker/ carb maker.


----------



## hankster (Jan 1, 1998)

What parts are you looking for? Generally, that is an expensive model to fix. If I'm not mistaken, Shindaiwa was the manufacturer of that model.


----------



## wrencher2b (Feb 19, 2005)

Thanks "bugman" and "hangster for your interest and responses.

Since I was last at the local Sears Service center (6 or 7 years ago), I've discovered that my service technician contact no longer worked there as all repair work was being sent out 200 miles away. Therefore, I wasn't able to get the info that was needed except that my brushcutter could have been manufactured as early as 1987.

Needless to say, Sears only has a few parts available for this model such as the foam air cleaner element and the fuel filter. However, what I really need, to begin with, is an owners manual.

Hangster, you thought that manuafacturer was Shindaiwa. Would you be able to search your vast knowledge base and provide a Shindaiwa model name or number for my brushcutter? Also, are you aware of any web sites, other than PartsAndService.com, Shindaiwa.com and M-And-D.com for illustrations that I might compare with?

Thanks


----------



## scrench (Dec 8, 2004)

" (636.796243 going by this robin made it


----------



## bbnissan (Nov 7, 2004)

By my sources... 636 is the code for Echo, but I could be wrong.

The brushcutter and engine are made by Echo (very good machine), but I'm not sure who makes the carb. All you need to do is find an echo dealer and you can get all the parts you could possibly want. I have to warn you though, that carb doesn't look like any Zama or Walbro carb (what Echo usually uses) I have ever seen so the parts are probably going to be hard to find and they will probably cost a little more. Also, the parts for the Echo are probably going to be more than you expect because it is a commercial grade piece of equipment.


----------



## scrench (Dec 8, 2004)

http://zacm.com/model/index.htm


----------



## bbnissan (Nov 7, 2004)

I stand corrected :thumbsup: 

I was really suspicous of my sources after I looked at the engine and carb diagrams...the Echo doesn't have a recoil or fan shroud like the ones in the diagram and the carb looks like nothing I've ever seen before.


----------



## scrench (Dec 8, 2004)

pretty cool link ? just stumbeled across it


----------



## hankster (Jan 1, 1998)

Check the Sears parts web site. Go to www.sears.com and click on the Parts link in the upper left side of the page. Plug in your model number and it'll pop up. They have quite a few parts listed that are available.


----------



## wrencher2b (Feb 19, 2005)

Supporting your understanding that ECHO is the manufacturer are OWWN.com and PlanoPower.com. However, GWI.net and ZACN.hypernet.net list the manufacturer (at least of the engine) as being Robin Trimmers.

This apparently conflicting information may coincide with the fact that the Sears 1992 Fall-Winter catalog lists the same 51.7cc "BrushWacker" (catalog no. 71 F 79624K) as being "imported" Therefore, this brushcutter just may be manufactured by ECHO and with a Robin (Trimmer) engine !!!! ????

With this in mind, I have redirected my search to the European market, with no positive feedback at this time.

As this unit is manufactured out of the U.S. and for sale outside of North and South America, the local ECHO dealer didn't have any information that would be helpful to me (The Robin Trimmer engine and the T-K carburetor, with a "tickler" valve on the bottom of it, baffled him.

I have been searching Ebay (international) to locate the imported ECHO manufacturers model name/number and googled , for hours, markets other than the Americas, with no positive results.

Any more ideas will be appreciated and quickly followed-up on.


----------



## bugman (Aug 12, 2004)

if you can't find what you need in time, go to a small engine shop, they would have your parts look up for you, and if you can't find anything else, it was most likely discontinued and there is hardly no parts for it, so i'd either part it out or sell it to someone else


----------



## wrencher2b (Feb 19, 2005)

:wave: 

Thank you, all, for your suggestions on finding the information and products for my Sears "BrushWacker"

"Scrench"... you got me going in the right direction...thanks.

"BBNissan"... many thanks to you for taking your time and researching the possibility that this was an imported ECHO product. However, your final determination, in concert with "Scrench's" web site find that this is a Robin Trimmer product, will be followed up on, starting now.


----------



## Jake321 (Jun 10, 2020)

I realize this is a very old thread and probably no one is still following, but I wanted to add my input. I found one of these Craftsman Bushwackers (636.796242, not sure what the difference between 242 and 243 is?) in an old garden shed. I have no idea how long it has been since it was used, but probably quite a while. The mud dobbers had built nests in it and it was pretty dirty but still looked usable. I cleaned it up and found it had a broken fuel tank, which I am repairing. I did get it to fire up but would not siphon fuel from the tank. This thread was invaluable in being able to find parts. What I did find out is that the unit was indeed made by Shindaiwa for Sears and it uses the same engine and other parts as the Shindaiwa B45 Brushcutter, also used on several other heavy-duty Shindaiwa products. As such many parts can be purchased through Shindaiwa parts suppliers. Also, I was able to find carb rebuild kits (TK Carb as noted in one of the posts above) and a new carb on ebay for about $15! I believe my problem is the check valve in the fuel pickup in the tank. Anyway, this thing is a beast of a trimmer and hope to have it back in action soon.


----------



## Shepherdpursuit (Jul 14, 2020)

Jake321 said:


> I realize this is a very old thread and probably no one is still following, but I wanted to add my input. I found one of these Craftsman Bushwackers (636.796242, not sure what the difference between 242 and 243 is?) in an old garden shed. I have no idea how long it has been since it was used, but probably quite a while. The mud dobbers had built nests in it and it was pretty dirty but still looked usable. I cleaned it up and found it had a broken fuel tank, which I am repairing. I did get it to fire up but would not siphon fuel from the tank. This thread was invaluable in being able to find parts. What I did find out is that the unit was indeed made by Shindaiwa for Sears and it uses the same engine and other parts as the Shindaiwa B45 Brushcutter, also used on several other heavy-duty Shindaiwa products. As such many parts can be purchased through Shindaiwa parts suppliers. Also, I was able to find carb rebuild kits (TK Carb as noted in one of the posts above) and a new carb on ebay for about $15! I believe my problem is the check valve in the fuel pickup in the tank. Anyway, this thing is a beast of a trimmer and hope to have it back in action soon.


Well, I am trying to source parts for my Brushwacker (636.796242) also, and just learned from Sears none are available. Use it every year on the farm.


----------



## pmeyers (Aug 3, 2021)

Jake, I ran across your post looking for information abut the Sears 51.7c brushwacker. I just bought one that hasn't been used in a decade and I am hoping to get it running again. Has good compression, and fires , so should run. Have ordered a carb from ebay. Running into a problem similar to the one you described with the fuel line from tank that also serves as a bulb primer. Primer won't pump fuel to the carb, and the carb doesn't lift the fuel to keep funning. Could you share with me how you solved this, if your did? I appreciate your help,
pmeyers


----------



## No1stunna (Aug 12, 2021)

It should pull the fuel once it’s primed, you could try the more modern carb like the one for the shindaiwa c350 or t270 that has a primer bulb on the bottom and modify the tank with a grommet where the original primer bulb is. I have 2 of the 51.7cc models, neither run but I’m currently working on one. I’ve successfully repaired one of the 37.7cc models but it was a bowl carb so I was able to make all of my own gaskets. This diaphragm carb poses a problem finding parts. If you’re really wanting the original primer bulb Try looking for parts for Shindaiwa b45, b45le, Makita rbc525, 525e, 526.


----------



## pmeyers (Aug 3, 2021)

No1stunna said:


> It should pull the fuel once it’s primed, you could try the more modern carb like the one for the shindaiwa c350 or t270 that has a primer bulb on the bottom and modify the tank with a grommet where the original primer bulb is. I have 2 of the 51.7cc models, neither run but I’m currently working on one. I’ve successfully repaired one of the 37.7cc models but it was a bowl carb so I was able to make all of my own gaskets. This diaphragm carb poses a problem finding parts. If you’re really wanting the original primer bulb Try looking for parts for Shindaiwa b45, b45le, Makita rbc525, 525e, 526.


Thank you the response and the info. I think that I am making progress. I made up a new fuel line with an aftermarket check valve that goes in the tank. I put a newer type bulb primer inline and everything seems to work fine. I now need to find a way to plug the old primer hole in the tank and allow the fuel line to come through with no leaking. I think that I can drill a hole in the old rubber plug and run the line through it with some sealant. I'll send a pic when done.
Another question for you since you have a couple of these. Do you know the bolt and thread size for the left handed nut that goes on the shaft on the gear head. I thought I measured carefully and ordered a 5/8 24 left handed flange nut but it doesn't fit, it's just a little too small in diam. Do you by any chance know what the actual size it is? Thanks for your help, pmeyers


----------



## pmeyers (Aug 3, 2021)

correction: I ordered a 3/8" 24 left handed bolt


----------



## No1stunna (Aug 12, 2021)

_Metric likely since everything on the machine is. I’ll try to remember to measure it and post back for you._


----------



## No1stunna (Aug 12, 2021)

It takes a 17mm wrench or socket


----------



## pmeyers (Aug 3, 2021)

No1stunna said:


> _Metric likely since everything on the machine is. I’ll try to remember to measure it and post back for you._


I was surprised to learn that there were metrics used on this machine in the mid 80's and sold by the heartland of American manufacturing, Sears. In any case I figure out that it is m10 x 1. Instead of ordering nuts I ordered a left handed tap and redrilled and tapped some 3/8 flange nuts to left handed m10 x 1. Worked great. Since it doesn't used a cotter pin to retain blade from coming off, I also made some jam nuts.
The original fuel set up was no good any more, the primer button was cracked and wouldn't work. So I made a line with a check valve and filter in the tank and fed through the original plug cap where the primer cap was and then to a separate primer bulb, then to the carb. Did make some rubber gaskets for the gas tank cap. Previously repaired a crack in the gas tank by plastic welding it.Works great and no leaks. Used it yesterday with the original 9" blade and it's a monster at cutting out the rabbit brush. Bladed dulls quickly so going to order a carbide tipped blade for it.


----------



## No1stunna (Aug 12, 2021)

I can’t figure out how to keep my gas cap from pissing when running. It has a little check valve disc, a clearish white plastic piece that looks like a top hat and the black screw cap portion. Does this sound like yours? Maybe I’m missing a piece? The check valve seems to work only allowing 1 way passage but it obviously isn’t dealing well when it’s rapped out.


----------



## pmeyers (Aug 3, 2021)

No1stunna said:


> I can’t figure out how to keep my gas cap from pissing when running. It has a little check valve disc, a clearish white plastic piece that looks like a top hat and the black screw cap portion. Does this sound like yours? Maybe I’m missing a piece? The check valve seems to work only allowing 1 way passage but it obviously isn’t dealing well when it’s rapped out.


Sorry for the delay in answering. I had the same problem. Disconcerting to feel gas dripping on my leg while operating the brushwhacker. So I used the white check valve as a template to mark the outer diam on a piece of rubber gasket material. I cut out rubber disc and put a small hole off center so it didn't line up with the hole in the cap.I then put it insde the screw on cap along with the white check valve. Air could still come in but there was no longer a direcr path for gas to piss out. You want the rubber seal to be on the flat side of the check valve. Worked for me.


----------



## Geektoe (8 mo ago)

pmeyers said:


> Sorry for the delay in answering. I had the same problem. Disconcerting to feel gas dripping on my leg while operating the brushwhacker. So I used the white check valve as a template to mark the outer diam on a piece of rubber gasket material. I cut out rubber disc and put a small hole off center so it didn't line up with the hole in the cap.I then put it insde the screw on cap along with the white check valve. Air could still come in but there was no longer a direcr path for gas to piss out. You want the rubber seal to be on the flat side of the check valve. Worked for me.


Wow !! I am just as surprised to find this thread as I was when I found the old machine that I put up at least 30 years ago because of the gas cap problem. Fresh gas and it lit right up however even with some of the fixes I still have gas pissing out. I’m trying to sort out new caps, anyone have an idea ? Thanks, Phil


----------



## Milton Fox Racing (May 27, 2014)

Geektoe said:


> Wow !! I am just as surprised to find this thread as I was when I found the old machine that I put up at least 30 years ago because of the gas cap problem. Fresh gas and it lit right up however even with some of the fixes I still have gas pissing out. I’m trying to sort out new caps, anyone have an idea ? Thanks, Phil


Just to confirm - is the gas leaking from the fuel cap opening still?


----------



## Geektoe (8 mo ago)

Milton Fox Racing said:


> Just to confirm - is the gas leaking from the fuel cap opening still?


Yep, the vent hole. I’ve tried a few things just short of blocking the hole entirely. I thought I had a winner with a primer bulb that fit almost perfectly in the white cap, put a small hole offset in it. It worked well for about 3 minutes.


----------



## Geektoe (8 mo ago)

Geektoe said:


> Yep, the vent hole. I’ve tried a few things just short of blocking the hole entirely. I thought I had a winner with a primer bulb that fit almost perfectly in the white cap, put a small hole offset in it. It worked well for about 3 minutes.





Milton Fox Racing said:


> Just to confirm - is the gas leaking from the fuel cap opening still?


I’m also wondering if this is an acceptable loss. It’s only at idle so it seems to be equalizing at higher speeds. I’ve been reading about some of the replacement “ Sten” caps and folks say the quality is not there. I had a thought about drilling the hole out and adding a small piece of tubing to act as a snorkel to bring the opening above the fuel level while running. A bit awkward when refueling but I’d rather not muck up my original cap just yet.


----------



## cooterscooter420 (3 mo ago)

I also have the same model and came up with a robin fuji engine model number NB50L


----------

