New Weedeater 22" side discharge mower - 500 Series B&S engine runs then quits

Model # 10T502-1022-B1, 158cc Briggs & Stratton engine.

I purchased this mower last year end of season as a backup to my older mower and really never used it after unpacking - filling with oil - checking blade/wheel bolts and everything just to make sure nothing left "loose at factory".
I even ran it with a little gas just to make sure it ran - and it did.

My older mower's frame rusted/broke, so I get this new mower out yesterday, drained what little gas was left in it from test run in Fall (I used a small diameter siphon-hose), filled with new gas, checked oil and the thing won't run except for the gas from priming - starts right up but then I think it just 'starves' for gas and quits. I take the spark plug out - clean and re-gap (.030) - re-install and it does the same thing. I mean it runs fine until the 'prime' gas runs out then just quits.

Two things:
1. I'm going to test with a new spark plug - although I don't think that's the problem since it starts so easily and runs for all of 5 seconds;
2. I saw another post about the gas cap vent holes being sealed up - starving the air flow on the gas tank - thought that might be worth a look;

Are there any other things I can do to isolate this problem? It's under a 2 year warranty but at this point engine shops are telling me they're operating on a 2 month backlog before they could get to me - plus I didn't buy it from them.
Honestly, I've never had a problem with a brand new mower out of the box until this one.
Thanks,
greynold99

 

Even though it is new you never know how long it had set on the shelf. I pulled 4 new mowers from a Wal-mart dumpster a few years ago, all same problem.
You need to install a new diaphram kit, it is Briggs part # 795083 or old # 495770 also Lowe's has a kit #5083 which has the same parts.
Here we go:

Remove air cleaner, there are 2 bolts that hold things together, one on the front of the tank 3/8" and one into the block 1/2", remove these bolts, now "slowly" slide the carb/tank off the intake tube and breather tube, now tilt the tank in to release the throttle linkage and waalaa the carb/tank is removed. Check the intake tube to see if the “O” ring seal and plastic retainer are still on the intake tube, if so remove them and re-install them into the carb. Remove the 5 screws from the carb/tank remove carb(don't loose the spring) now spray all holes, cracks and crevases in both the carb and tank surface with brake parts cleaner, remove the main screen(looks like a thimble), now with a small screwdriver pry out the main jet(carefully) and clean it, check the “O” ring on the main jet for damage, if it is damaged it must be replaced, reinstall the jet, it can be difficult some times to get it to snap back in place(I use the rounded end of a screwdriver handle). Remove and clean the fuel pickup stem(not necessary if the fuel tank was clean). Clean any junk/rust from the tank. Install the diaphram on the tank then the gasket(no goo or sealer) now carefully replace the carb(the spring will try to misalign the diaphram), tighten all screws a little at a time so as not to crimp the diaphram until they are all tight. Install the carb/tank in reverse order and you are done. If I missed something one of the real mechanics will correct me. Have a good one. Geo

 

I got your instructions and will have to pick up a carb diaphram rebuild kit this weekend. Will update after I get the job done.
Again thanks,
greynold99

 

Kit should be less than $5. Have a good one. Geo

 

It turned colder here in PA last weekend and I finally got the new diaphragm kit in yesterday. Everything was just as you said but being it's a completely new engine I didn't find any rust or debris on the pickup tube screen or the the jet screen. Checked anyway and sprayed with GumOut just to be sure but all the orifices were clean. Carefully put everything back together and tried to start - Same results. After starting it runs until the prime gas is gone and then dies.

Any other ideas?
Thanks,
greynold99

 

The part about cleaning the main jet in Geogrubb's post... did you do that? That's where the problem should be.

 

Thanks Cheese,
I didn't have the instructions in front of me and I thought he meant the smaller diameter pickup tube, which was perfectly clear/clean... I'll pull that carb off again and check the main jet under the 'thimble'-sized screen. Sounds like you're expecting some kind of obstruction or foreign matter to be found there.
greynold99

 

Yep, probably gummed up gas varnish or residue.

 

When I pull out the "main jet" geogrubb referred to above - I have a small white plastic piece no larger than a ball point pen body at the top with the O-rubber washer that fits into the tube. It's about a 1.5 inch long and it reduces in size/diameter to about the thickness of a ballpoint pen's ink tube for an inch.
The smaller end of the tube has 3 tiny holes near the last half-inch of the tube on one side - and only 2 tiny holes on the opposite side.

On the larger top where the rubber O-ring washer is - when I look from the top I see what appears to be an small hole partially through (looking down on it) but when I try to push a piece of small diameter wire from either the top or up from bottom - it does not go completely through.
It's not gummed up or anything - it just was not drilled completely through if it's supposed to be open.
Anyway, that's my question - Should that little white plastic piece that I pried out have a hole clear through the top (larger part of the tube near the O-ring) to the smaller part of the tube?
Thanks guys,
Greynold99

 

Yes, that is the main jet/nozzle, it should have a hole all the way through. It is where it gets the gas to run. If it was never open, it never would have run before when you tested it, so there just about has to be something blocking it. Go to a hardware store or welding supply store and buy a set of torch tip cleaners for welding torches. They are $5 or less. These are different sizes and are strong enough to push through the hole without bending when they hit the obstruction.

 

Cheese,
I stopped by my local B&S Authorized Service Center with my carb in hand, and asked the service guys behind the desk about the 'hole' in the center of that little plasic piece - the answer I got was this: '... they didn't know but for $65 bucks an hour you can talk to our mechanic'. Guess I wont' be buying anything there.

Anyway, I got an idea. Remember the old 15yr old Murray mower that failed? I pulled the carb off of it to see if it had a hole down the center of that white plastic piece - and it did not either.
Looking at it more closely, I realized that the 15 yr old carb and the new one was the same. Well, it was the mower frame that failed on the old mower, so I took off the carb - cleaned it up with GumOut and mounted on the new mower with the new diaphram kit - and it started right up and ran. I ran it for about an hour and it continued to run fine.
Something is wrong with the new carb or they've changed something in the internal design - for whatever reason I don't know since the design is reliable as far as the old carb working indicates.

I called another B&S Service Center in the area and turned out they had another of these Weedeater mowers there with the same problem. I didn't buy the mower there but purchased a high end Echo brush trimmer there last year so I asked if the owner would be able to give me a new mower carb under warranty, as a favor. (Supposedly there's a 2yr B&S warranty, but I'm finding out how hard it is to get a business to provide warranty repairs if you didn't buy it from them...)
Do you know anything or have experience with direct warranty support from B&S? I hate having to pay an additional $30 for a new carb on top of the nearly $200 for the mower...
Thanks for your help.
greynold99

 

It can be difficult to get warranty on something, especially a carb, from someone you didn't buy it from and without receipt of purchase. With receipt and in the warranty period, it can still be hard to get a carb warrantied.

I never saw a main jet without a hole through it (how would the engine get it's fuel?). I just popped one out to look at it and sure enough, the hole goes all the way through. I thought maybe I would see something that might make it appear that it doesn't, but I can see light through it. Maybe I'm missing something...

 

Cheese,
Thanks for taking the time to look... I used medium paper-clip that appeared to fit the 'apparent' hole recess on the inside of the white plastic tube on both the new and old carbs - neither allowed the wire paper clip to pass. I didn't take the old one out at that point, and only tried it from the side you can see (needless to say, I wouldn't have been able to look through it either) but that's when I noticed the carbs were exactly the same and knew the old mower was running before the frame gave (rusted) out.
I guess at this point, don't have anything to lose - I could just drill out a 1/32" hole clean thru and if it was an obstruction then it should run.
You did notice that the white plastic 'thicker' end has a flattened place on it where it sits at the mouth of the main jet - which I took allows the gas to pass thru... I could be mistaken but this carb design is so reliable - How/Why could/would they've changed anything about it - given they've been using it for at least 15 yrs and probably longer.

I also Google searched around and have found at least 6 or so reports of people reporting similar issues with B&S engines on Weedeater 500 mowers - Most however get at least a several hours of operation out of them before they start stalling out after starting...
thanks agai,
greynold99

 

Drilling a hole won't do it unless you get the hole to the exact size. A few thousandths of an inch too large or too small can cause it to run badly or not at all. It's pretty precise. I'm pretty sure the paper clip is too big to go through the hole. I think the hole necks down smaller inside. A paper clip wire is too big to go through even some of the large riding mower engine jets, even the 2 cylinder engines. Try the wire out of the middle of a bread bag twist tie.

 

As Cheese suggested, I always use the wire from a twist tie, it cost nothing and is the proper size. Have a good one. Geo

 

Thanks Cheese & Geogrubb

That hole is 'significantly' smaller than the paper clip I was using and it does appear there was an obstruction as I encountered the tiniest resistance as the wire was punching thru. I can see light thru the end of the tube now, and thanks to you - also the light at the end of the tunnel for this repair.
Will reinstall and let you know.
greynold99

 

Just a quick update...
I went on the BriggsAndStratton.com website to register the engine but didn't find any 'Register Product' category for pushmower engines so I entered all of my information on the 'Contact Us' e-mail form that comes up.
Well it took a few days and a couple of exchanges of explaining the situation with inability to get warranty work done when you didn't originally buy from the B&S Authorized Repair/Dealer - but Scott R. @B&S said he'd send me a replacement carburetor.

I haven't had time to test my repair on the nozzle-jet on the original carb yet and at this point, I'll wait till I have the new one. But it does go to show you that some times companies do care about their customers and will work with you to resolve your problem.
Thanks again all,
greynold99

 

Yes, they sometimes will if you talk to the right person, but this should never have been a warranty issue. This isn't the mowers fault. The jet got clogged after you got it. The fuel that was left in it gummed it up. Not Briggs fault, so it's good of them to send another for sure.

 

Cheese,
I just recv'd the new carb - and they've changed the design of the main pickup where that 'piston-shaped' plastic insert goes up into the main nozzle. Where the smaller hole went up through the head-of-the-plastic piston thru, to the shaft - it's now a molded-stainless steel insert about a 1/16" wide.
I knew there had to be a design-flaw just given the number of reported issues around this particular series of engines. I mentioned 6 in my earlier post, but I kept finding more reports on this particular 500 Series B&S engine where the mower would maybe start/run for a while out-of-the-box - maybe several times even or not at all, as in my case; but eventually - and this was consistent on most of the reports- would run off the prime-gas and then not continue to run, it would just die. The one poster who responded to my issue indicated he found several of these brand mowers in a Walmart dumpster - which indicates to me a consistent engineering defect because Walmart was getting tired of dealing with the exchange/refund hassle. And, in fact of the 2 or 3 Walmarts in my area that I've been to recently, they only carry the Weedeater brand weedeaters but no Weedeater mowers.
Again, I greatly appreciate your help and have learned a great deal from your replies to other posts.
greynold99

 

Great! Did you put it on? I haven't noticed any with the stainless piece yet. The plastic ones have been around for probably 20 years and do well overall (for a cheap engine it holds up well). I guess the main jet is still the same on the new one?

 

I didn't notice if you put the warranty # or could you tell us what the new carb. number is, my brother in law has a mower with I believe the B&S 500 series, I also have one, that needs rings!!!!!!