carb spits fuel

[8HP]

8 HP B&S from '94 (powering a woodchipper) spits fuel while running. Engine sat for years. I replaced carb with new aftermarket carb. Only carb available. Engine starts and runs, no surging. Engine running at low speed fuel is seen gushing from brass pipe from fuel bowl to throat of carb. At full speed all fuel is going into cylinder. Engine exhaust is black from too much fuel. At low speed it puddles up at throttle valve, then drips down Air/Cleaner side. Engine vibration normal. No fuel in oil or coming from exhaust or crankcase breather hose to air/cleaner. Engine off, no fuel leaks from needle/float. Is fuel pump pumping too much fuel? I changed fuel tank to gravity fed. No change in carb behavior. What causes this? If fuel needle/float not leaking with engine off, why is too much fuel being pushed out of float bowl when engine on?

 

[slomo]

Engine sat for years.

First red flag for me. Everything needs to be looked over. Mice, corrosion.......

I replaced carb with new aftermarket carb. Only carb available.

Got to do what you gotta'. Might have to verify throttle, choke and needle are working proper in new carb. Get drill bits and measure the main jet for similar/same size. Use the dull end that goes into the chuck for this. No need to drill out any jets here.

Engine starts and runs, no surging.

Okay nice to hear.

Engine running at low speed fuel is seen gushing from brass pipe from fuel bowl to throat of carb.

Sounds normal, fuel coming from emulsion tube yes into air stream.

At full speed all fuel is going into cylinder.

Nice.....

Engine exhaust is black from too much fuel.

Choke plate stuck closed or half mast? Verify choke is working proper. Next is pressure testing carb needle. You will or could have "some" soot in the muffler. Shouldn't be like a steam engine locomotive though.

At low speed it puddles up at throttle valve, then drips down Air/Cleaner side.

Leaning more towards carb needle sticking open to me.

Engine off, no fuel leaks from needle/float.

You can't see this normally unless you open the choke plate and look into the carb throat/emulsion tube area.

Is fuel pump pumping too much fuel?

Could be and overwhelming the needle. Again need to pressure test the carb needle and verify pump is working into a glass jar.

 

[8HP]

Thanks for your input. I keep going to problem with needle/float. Back to basics good idea!

 

[8HP]

Thanks for your input. I keep going to problem with needle/float. Back to basics good idea!

FOUND PROBLEM!! Fuel needle/set won't hold pressure. Cleaned needle and brass seat. Will hold pressure at 5 PSI. I pumped 10 PSI into needle valve. Looses pressure quickly till down to 5 PSI. Needle has a Viton tip. I don't have a small engine needle with a Viton tip that fits. Time for another $20 carb.

 

[slomo]

Normally 7psi is the ticket. So close to 5 LOL. Glad to hear you are on to something.

Wet the needle and seat with PB Blaster penetrating oil and test at 7psi for 30+ minutes. Not WD-40......

 

[8HP]

Normally 7psi is the ticket. So close to 5 LOL. Glad to hear you are on to something.

Wet the needle and seat with PB Blaster penetrating oil and test at 7psi for 30+ minutes. Not WD-40......

Wet needle and seat with PB Blaster. Will hold 6 PSI for several minutes. Then won't hold pressure. Put carb back on engine. No change. Starts and runs, spits out fuel.

 

[slomo]

Needle and seat no bueno.

 

[slomo]

Need your engine numbers to know what carb you are buying and such. Wondering if you have the wrong carb on it possibly??

 

[8HP]

Need your engine numbers to know what carb you are buying and such. Wondering if you have the wrong carb on it possibly??

B & S model: 192432 type:012201 code:9408261B. I'm told carb #497581.

 

[slomo]

Looks like you need Briggs 497038.

Your date code is

9408261B