B&S120000 - Recurrent Carb Issues

[rave0035]

Hi - first time post. This question is about a B&S 120000 / 205cc model engine attached to a (gasp!) Simplicity snowblower. It uses a 765485 carb and I only run non-oxy gas.

Here's the situation: I received the snowblower about 4 years ago as a 'hand-me-down' running poorly - the carb was all gummed up, so I decided to replace vs rebuild. I replaced with a cheap Chinese knockoff from Amazon and it's been running fine ever since. When I replaced the carb, I also added a fuel shutoff and every year at the end of the season I run the carb dry.

This winter, when I got the blower out of storage, the carb immediately overflowed when I opened the shutoff. Stuck needle I assumed, so I took the unit apart and cleaned everything and checked the float. No luck - same issue upon reassembly.

I decided to replace the carb with an OE Briggs unit. When I fitted the new carb, it immediately had the same overflow issue as the old carb. This should have been my signal to do more troubleshooting but I needed a working snowblower so I messed with the float level until I got it to run well and stop leaking. The snowblower runs well but yesterday after clearing the driveway the leaking started again.

Help! I really don't know where to look next. The easy (wrong) solution would be to fit an access for the fuel shutoff and just turn off the gas after every use, but I don't like the idea of running an improperly adjusted, fire-hazard snowblower if I can help it.

Thanks in advance,
Mike

 

[Scrubcadet10]

I would replace the fuel line or first check it for detoriation. Not uncommon for chunks of it to wedge in the needle and seat hold it open. As well as trash in the fuel tank.

 

[StarTech]

Would not hurt to install a fuel filter too while adding new fuel line. One that is about 70 microns for gravity fed system.

Meanwhile off I go to relocate a 15-20 lb Snapper to a local creek. He should be hibernating this time of year.

 

[rave0035]

Sounds good - I'll give it a shot and report back. Many thanks!

 

[VRR.DYNDNS>BIZ]

Sounds good - I'll give it a shot and report back. Many thanks!

I have had 7 new carb floats act up! Float problems can be intermittent, particularly when not in use. When running, the vibration often stops the problem. Biggest thing we have done that helps tremendously is add some 2 cycle oil to the gas to lubricate the rubber tipped needle of the needle and seat assembly so that it finally slips into position to seal the gas under the pressure of the float.