Export thread

2013 TroyBilt Pony. Briggs & Stratton model 31c707-3026 G5, 17.5hp. Bought used April '19. Changed oil, replaced spark plug and fuel filter at that time. Ran fine until last week. Used it for about 20 mins, stopped to empty grass catchers and wouldn't re-start, no matter what.

What I've done:

1. Replaced spark plug, although the one from April looked good.
2. Used an ignition/spark tester - saw ZERO spark no matter how I set the tester.
3. Ordered new coil. While waiting for new coil to arrive used a wire wheel to clean rust from flywheel and magnet.
4. Replaced Coil/Magneto. Briggs & Stratton website said the original coil was replaced with a model #595304 coil, that's what I installed.
5. Installed and gapped new coil per instructions.
6. Tried starting the mower. The engine ignited for about 3-4 seconds then shut off and NEVER re-fired.
7. Used ignition tester again. Consistent spark seen at the tester's gap size shown in the pic. I do not know which lines on the tester's Small Engine (SE) section represent an approx .30 gap. NOTE: When I adjust the tester any farther out than pictured the spark becomes intermittent.

Fuel (ethanol-free) is fresh, no water.

Does the tester's spark gap shown in the pic confirm that now the coil is working properly?

Please, what's next?

Thanks, Ken

The carb solenoid might be failing. Try to feel or listen for a clicking noise when the key is turned on and off at the carb.

Spray some carb cleaner into the carburetor through the air intake behind the air filter. If it fires then dies you know it's a fuel delivery issue.
Either like Luffy said the solenoid
Does it have a fuel pump or gravity fed?

One step forward, 3 back. Grrrr!

I was checking over stuff before starting the fuel troubleshooting and saw that I had left the wiring harness disconnected after I cleaned it the other day. STUPID! Re-connected it and tried starting. Cranked right up! Cool! Let it run for a few mins and did good. Was elated. Shut it off and put everything back together, engine cover, hood, etc. Restarted and drove it around the backyard w/blades engaged for about 15-20 minutes. Mostly wanted to recharge the battery. Ran fine. Shut down and tried quick restart to seee if battery charged, strong crank and started fine.

Went inside for about 30 minutes and came back to it. Tried to start but NOTHING. Flywheel turned maybe half a revolution then THUNK and stopped. Tried a few more times and same.

Then started smelling GAS, REAL strong. Opened hood and the carb was covered in gas. Wiped it down and more appeared. Looked like it was coming from around the (?) throttle shaft, see pic. NOTE: When I was cleaning everything a few days ago, brushing dirt off the carb w/a paint brush, I found a half piece of what appeared to be washer or spacer coming off that same shaft with the spring. Kinda looked like it was made of foam? It was deteriorated so hard to tell. ALSO, gas was seeping out of the hose (at carb) that feeds gas from carb up to top of engine block.

THEN, I glanced down to left and saw gas RUNNING out of the lower front of the mower, out of the MUFFLER. WTH!

With that, and gas still seeping out of the throttle area, I crimped fuel hose from tank and disconnected it.

1. Why/how did so MUCH gas end up in the engine to run out of the muffler?

2. Does the engine 'thunk' mean anything?

Where do I go from here?

sounds like the needle and seat in the carburetor has failed. it limits the fuel allowed into the bowl, when it fails. fuel keeps coming in the bowl and goes out any exit. there might be alot of gas in the combustion chamber causing it not to turnover.
there is usually a little piece of material around the throttle shaft to keep dirt out etc.

your crankcase might also be full of gasoline too. do not start it until oil and filter are changed.

Scrubcadet10 said:

sounds like the needle and seat in the carburetor has failed. it limits the fuel allowed into the bowl, when it fails. fuel keeps coming in the bowl and goes out any exit.

Click to expand...

How do I confirm and fix that? Rebuild carb? Never did that but if I can find adequate instructions no problem trying.

there might be alot of gas in the combustion chamber causing it not to turnover.

Again, How do I confirm and fix that?

there is usually a little piece of material around the throttle shaft to keep dirt out etc.

your crankcase might also be full of gasoline too. do not start it until oil and filter are changed.

Don't think there is an external oil filter. Didn't see any gas on dipstick but have no problem changing oil.

Yes, either rebuild or replace carb .Okay, I'm just listing the common problems that accompany the needle and seat failing. I have not seen a carburetor flood before that did not have the needle and seat fail.
Take out the spark plug and try to start the engine, if it spins over easy, you may have a valve problem, if it spits out a bunch of gas the chamber was full.
Be sure to smell them oil on the dipstick too. Just to be safe.
The only way for gas to run out the muffler is through the combustion chamber.
If I am thinking right that hose that comes from the top of the block to the carb, it is some sort of vent hose that puts the air back into the intake system. I think it's an EPA deal.
In the first picture, is that black hose coming from the air filter, correct?

https://www.partstree.com/models/31...-engine/carburetor-kit-carburetor-overhaul-3/
you are going to have to find out if you have a Nikki or Walbro carb. the walbro carb should have LMT stamped in it somewhere, and the NIKKI should say NIKKI on it somwhere.
the overhaul kits are 121 and 121A in the parts list. 121 is for one carb 121A is for another brand.

of course you might can find a cheap chinesium on Scamazon or EvilBay if you want. or a new carb, its your money :wink::biggrin::2cents:

of course if you want to wait and see what anyone else has to say what it might be go right ahead
you wont hurt my feelings by wanting a 2nd opinion

No need for self doubt you are quite right.

For Ken's benefit.
Because of idiot EPA regulations the old external drains on carbs have been banned.
So before that you wouls see fuel dripping from the carb & know that the float needle was stuck open.
Now days the drain is INSIDE so the entire contents of the fuel tank can leak out, through the carb into the cylinder, past the rings then fill the sump.
Thus you now have a couple of gallons of waste fuel oil mix that is no good to anyone.
You will need to drain and replace the oil at least twice after fixing the carb.
You will find very detailed picture book instruction for cleaning your carb here https://outdoorpowerinfo.com/repairs/

Verify that the float valve is working by holding the carb upside down and trying to blow through the fuel inlet.
If you have a pressure tester it should hold back 10psi or better.
Then hook it back up but leave the bowl off .
Let the fuel clamp off and hold the float with our hands .
IT MUST cut off the fuel flow before it runs out of movement.
Once you have that sorted, it is change the oil, run the mower for 5 minutes or so then change the oil again + the filter is your mower has one.
While you are playing with the carb & fuel lines, get an inline fuel tap and put it in the fuel line before the first other componant so you can just turn the tap off when you change filters, pumps or carbs.
Next time you mow. check the oil again, if it still smells like fuel then change it again.

Scrubcadet10 said:

Yes, either rebuild or replace carb .Okay, I'm just listing the common problems that accompany the needle and seat failing. I have not seen a carburetor flood before that did not have the needle and seat fail.
Take out the spark plug and try to start the engine, if it spins over easy, you may have a valve problem, if it spits out a bunch of gas the chamber was full.
Be sure to smell them oil on the dipstick too. Just to be safe.
The only way for gas to run out the muffler is through the combustion chamber.
If I am thinking right that hose that comes from the top of the block to the carb, it is some sort of vent hose that puts the air back into the intake system. I think it's an EPA deal.
In the first picture, is that black hose coming from the air filter, correct?

Click to expand...

the hose comes from the air filter housing just before it enters the carb.

Thanks guys for the good info.

Decided to buy a new carb. Found a B&S OEM #594593 here https://www.amazon.com/gp/product/B01IQXE5CG , decent price, fast delivery. Also ordered a shut-off to put in the feed line. Is there anything else I need??

I watched a few videos on rebuilding that carb and it seemed doable but the idea of a turnkey fix won out.

Drained the oil. No surprise but definitely gas was in it.

I am able to turn the flywheel. There is a resistance point but am able to push through it and hear air escaping.

Ken

Hope it comes with new gaskets.:wink:
You *might* can get by with reusing the old ones, but air leak could start it surging.

Scrubcadet10 said:

Hope it comes with new gaskets.:wink:
You *might* can get by with reusing the old ones, but air leak could start it surging.

Click to expand...

It comes with an intake gasket. What else is needed?

KenH99 said:

It comes with an intake gasket. What else is needed?

Click to expand...

Oh okay, I did not see that it came with the gasket. That should be OK

Cranking with fuel in the combustion chamber can blow the head gasket.
Always best to pull the spark plug & rotate the engine by hand a few times to expell excess fuel.
Cranking the engine cab cause the ejected fuel to ignite, not fun.

I'm back. Weather and other tasks have delayed getting this done. Received new OEM carb and installed. Having a major problem getting the choke to work.

1. The new carb's choke shaft spring was loose when I got it. I think I got it attached properly but can't be sure because no instructions to guide me. I will say it's a stronger spring action than the old carb.

2. I re-attached the throttle rod and spring and the choke lever then installed carb.

3. When the throttle/choke control is moved to the full up or choke position it does NOT move the choke. It seems that the angle is wrong to get the correct leverage.

4. The cable is adjusted to the max.

5. Please check the pics and see if any of you can spot something wrong? Installed properly?

Suggestions appreciated!


Here are links to two short videos that show the problem much better than I can describe. One is just a higher res version than the other.

https://youtu.be/8RHimWn_W4A

https://youtu.be/F-vuLhFCjzU

Thanks, Ken

I notice there are 1 or 2 other holes in the choke arm on the carb. Might try
A diff hole. I know it's a pain in the butt to take off stuff, and put back on,take off, put back.
:2cents:

Scrubcadet10 said:

I notice there are 1 or 2 other holes in the choke arm on the carb. Might try
A diff hole. I know it's a pain in the butt to take off stuff, and put back on,take off, put back.
:2cents:

Click to expand...

Did that. Tried both of the holes on that side of the arm. No difference. Didn't try the hole on opposite side because it would just pull the choke linkage even farther away from the (? governor control) lever.

Choke shaft is broke. There is supposed to be a stop tab to prevent the shaft from rotating past the point where the choke butterfly is straight. That tab is broke off of the shaft allowing the shaft to over rotate and then jam like in the picture and the video.

ILENGINE said:

Choke shaft is broke. There is supposed to be a stop tab to prevent the shaft from rotating past the point where the choke butterfly is straight. That tab is broke off of the shaft allowing the shaft to over rotate and then jam like in the picture and the video.

Click to expand...

Thank you.

That's a brand new (supposedly) B&S carb! From B&S via Amazon. Just confirmed that by comparing to old carb. That's probably why the spring was loose when I got it. It looks like I can't switch the choke shaft w/old one because the new butterfly has nubs on both sides to prevent it from being removed from the shaft like I could do with the old one.

Damn.

With a large set of pliers, pull the choke shutter out, and rotate the choke shaft until the lever is on the other side, then re-install.

Are you sure that the vendor is really B & S ?
AFAIK B&S do not retail directly they wholesale to their dealers who retail to the public.
As for buying off Amazon / Ebay
have said it 1,000 times but no one seems to listen.
A 10 year old can set up an ebay/amazon shop that looks like they are a long times experienced major dealer the flog off trash they have bought as scrap metal.
In 7 years as a technican who buys from real aftermarket companies ( Stens, Rotary Prime Line & Oregan ) the only things that have caused me grief were;-
Fuel taps that had neoprene seals, a 25 pack replaced without question
Honda gear change springs that broke, again replaced without charge ( slight delay on them )
Chain Saw bar with lamellar fracturing, the batch was recalled & replaced
And that is for around $ 300,000 worth of parts

Why people play parts roulette on ebay & Amazon for the sake of a few dollars is some what beyond belief.

bertsmobile1 said:

Are you sure that the vendor is really B & S ?
AFAIK B&S do not retail directly they wholesale to their dealers who retail to the public.
As for buying off Amazon / Ebay
have said it 1,000 times but no one seems to listen.
A 10 year old can set up an ebay/amazon shop that looks like they are a long times experienced major dealer the flog off trash they have bought as scrap metal.
In 7 years as a technican who buys from real aftermarket companies ( Stens, Rotary Prime Line & Oregan ) the only things that have caused me grief were;-
Fuel taps that had neoprene seals, a 25 pack replaced without question
Honda gear change springs that broke, again replaced without charge ( slight delay on them )
Chain Saw bar with lamellar fracturing, the batch was recalled & replaced
And that is for around $ 300,000 worth of parts

Why people play parts roulette on ebay & Amazon for the sake of a few dollars is some what beyond belief.

Click to expand...

Didn't play roulette. Amazon listing clearly states from "Briggs & Stratton". The carb is stamped w/same and box is as shown in the pics.

Fish said:

With a large set of pliers, pull the choke shutter out, and rotate the choke shaft until the lever is on the other side, then re-install.

Click to expand...

Please clarify what you mean by "choke shutter"?

KenH99 said:

Didn't play roulette. Amazon listing clearly states from "Briggs & Stratton". The carb is stamped w/same and box is as shown in the pics.


View attachment 46257View attachment 46258

Click to expand...

Briggs was not the vendor
Read the description carefully
It says it s an OEM part & replaces 796109
IT does not say that it WORKS

Lots or parts out there that should have been scrapped end up being sold on line.
If it came from the same factory then it is "genuine & OEM"
however if it came from the same factory in a truck load of defective parts that were supposed to be pulled apart & melted down it would still be " genuine & OEM "

Unless it says "Shipped by B & S or Sold by B & S "in the side bar, it has come via another vendor.

bertsmobile1 said:

Briggs was not the vendor
Read the description carefully
It says it s an OEM part & replaces 796109
IT does not say that it WORKS

Lots or parts out there that should have been scrapped end up being sold on line.
If it came from the same factory then it is "genuine & OEM"
however if it came from the same factory in a truck load of defective parts that were supposed to be pulled apart & melted down it would still be " genuine & OEM "

Unless it says "Shipped by B & S or Sold by B & S "in the side bar, it has come via another vendor.

Click to expand...

"It says it s an OEM part & replaces 796109"

The B&S website parts lookup gives the same info. the 796109 has been replaced with this part number. It's the correct carb.

"Unless it says "Shipped by B & S or Sold by B & S "in the side bar, it has come via another vendor."

Maybe you're unfamiliar with the practice of manufacturers stocking items with/at Amazon for order fulfillment, a quite common practice. Just because Amazon fulfills an order does not mean it's not authentic. In fact, this particular item's Q&A section has answers from Amazon's verified name badge "Manufacturer". I strongly doubt that B&S would be answering questions on a different vendor's listing.

In any case, my guess is either someone in the factory let a broke carb get past QA, or a returned carb got placed back into stock.

Update

Went on Amazon Thurs. and set up a return/exchange for the defective carb. They immediately began the ship process of a new carb. Dropped the return off at local Kohls yesterday. Received the new one around 11am today. That's custromer service.

Installed the new carb. The choke was just a little short of fully closing. Loosened the cable and really forced the cable back, it moved maybe 1/16th inch. That was enough. Reattached everything. Opened fuel line (added a shutoff and new filter) and the damn thing fired off first try. Let it run about 15 mins. Throttle works fine. Ran smooth at any speed.

As suggested earlier will change the oil again (2nd time) after I buy more.

Hopefully, this thing will do fine for a while. It better with the all the $$ I've put into it with new blades, tires, coil and carb.

Sincerely appreciate everyone's help!

:thumbsup::cool2::cool2::banana::thumbsup::drink: