Toro Mower

[lefty]

Toro mower

Machine:
Mod 20339C
Serial 314000194

Enigine:
Briggs
128M02-0017-F1

Code: 14021458

Manf Date 2014

Serial 1402145872844

This came to me with a fast surging problem. Cleaned the carb but am still getting a kind of fast surging. When I close the choke just a bit, which is the air vane type, it runs like a champ. So I'm assuming I have a fuel delivery problem. Fuel line is clear and it runs the same off a fuel cell. Cleaned the carb twice. Seams like a super simple carb. No adjustments. Seems super clean. Not sure what's next. Any help would be appreciated.

Thanks
Lefty

[KE4AVB]

Make sure the main jet is very clean and it may even need resizing a little. I already had two carburetors this Spring that the jets had to be resized.

[Fulltilt]

Have you double checked the intake manifold for cracking? Good mtg. gasket and tight? I always grease the mtg O ring. Tank screen clean? Absolutely sure no water , right?
Personally, I've never had to "resize " any jets on them carbs.

[lefty]

Thanks guys. So the main jet is supper clean. I didn't notice any cracking on the intake. I was wondering about that o-ring though...maybe sucking a bit of air. So do you use just an all purpose grease on the ring to make sure it seals up tightly?

As far as the tank screen, I'm guessing that's fine because I got the same results while running off of my auxiliary fuel tank.

Thanks again.

[Fulltilt]

Thanks guys. So the main jet is supper clean. I didn't notice any cracking on the intake. I was wondering about that o-ring though...maybe sucking a bit of air. So do you use just an all purpose grease on the ring to make sure it seals up tightly?

As far as the tank screen, I'm guessing that's fine because I got the same results while running off of my auxiliary fuel tank.

Thanks again.

They usually crack on the underside facing the cyl. Yours only being a few years old, probably ok.
Any old grease will do. It's a lawnmower, no?

[38racing]

If you leave choke open does the surge go away when putting it under cutting load? That would indicate that the idle circuit still isn't passing enough fuel in no load.

[lefty]

If you leave choke open does the surge go away when putting it under cutting load? That would indicate that the idle circuit still isn't passing enough fuel in no load.

Unfortunately, we still have some snow on the ground and no mowable grass to speak of. So I haven't really been able to put it under load. I'm going to call the owner to find out.

Although one can never be 100% sure as we don't have x-ray vision, I feel pretty confident that I got the carb as clean as I can at this point. Cleaned it twice so far.

In the mean time, I think I may take some of the prior advice and remove / inspect the intake manifold. I've never done that and am interested in exploring a bit.

[lefty]

I removed the intake manifold and gave it a check. No cracks. Cleaned the carb again. Still having the same problem. Greased up the o-ring before reinstalling the carb. I'm stumped on this one. Still purrs like a kitten when I choke some air off but pulses with choke open. New carb maybe? Or o-ring?

[lefty]

Owner says it will sometimes run pretty good and after dumping grass, when restarting it will do the surging pulsing. Some times it will do it on the first start. Sometimes it will stall and need to sit for a while before restarting.

[bgsengine]

outta do a leakdown test - possible burned exhaust valve, or check valve clearances

stray air being sucked back in through exhaust could do that too.