gas flooding engine on generator

I have a small generator with a B&S 11hp engine, model 256412-1153-E1 that is flooding the engine with gas. It seems to run right from the tank into the engine ending up in the oil sump. I didn't find this out until about two gallons of gas drained out of the tank since the last time I ran it about 3 weeks ago.

I had noticed a fuel drip about an hour after shutting it off and noticed the fuel lines were dried out. So I shut the fuel line valve until I could mess with it. I got some replacement hose and swapped out the three lines thinking I had fixed it. Tried starting it up and had gas flooding out of the breather tube. I unscrewed the oil fill plug and had the gas/oil mixture gushing out of there. I took the carb apart thinking the bowl float was sticking but there wasn't any fuel in the bowl. I cleaned it anyway and put it back together and had the same thing happen again. I am fairly certain that I didn't get the fuel lines messed up going to the fuel pump because I drew out the layout before taking them off. I don't have much experience with engines but I do know the basics of replacing a carb and was hoping for some suggestions on where I should look next. Thanks in advance...

Sounds like the fuel bowl float located inside of the carburator is stuck open. This usually occurs when there is dirt in the gas and it travels into the carb. I don't know what type of carb is on that engine but you need to get at the float and clean it out where the needle and seat meet. The fuel needle is connected to the float and shuts off the gas when the bowl fills with gas and sends the float upwards, it controlls the level of gasoline in the carb. The float floats upwards as gas fills the bowl area of the carb. After the float raises to a certain level it presses the needle against the seat and shuts off the flow of gas. This is not occuring on your engine so the gas continues to run into the engine causing it to flood, this will also cause gasoline to get into the oil sump. After you correct the gas problem chang the oil!!!! Another problem to watch out for is some times the float goes bad, it developes a small pin hole in it the float and it fills with gas. If you remove the float and shake it there should not be gasoline in it, if there is get a new float.

Added to my last post. The needle has a viton tip (Like a rubber) that goes bad and it is hard to tell when it does, this causes a bad seal between the needle and the carb body, if in doubt replace it. The bowls some times need to be leveled if you fool with them. If you get a carb kit fot that carb there will be instructions in the kit on how to level it. It is very simple.

Varnish in the bowl and the float/needle is hanging up. Time to tear the carb down and clean everything with solvent. Pick up a basic rebuild kit...at a minimum you will want a few gaskets.

Sounds like the float is sticking and draining into the intake valve when it is off. OHV? Be sure you turn off the gas when you aren't using it. I run mine until it uses all the fuel in the bowl then sputters out. Some of the newer engines use a plastic float so there is no adjustment tab. I don't think B&S used a fuel pump like some older motors. Drain that oil gas mixture out of the crankcase as that will ruin your engine in no time.

Metering needle is not sealed. Maybe bad needle, maybe bad float. Gas is free-flowing right past Metering needle, into breather hose, and right into crankcase.
Remove carb and clean, check that needle is good, check that float is not 'gas'-logged, drain tank and clean it out, replace fuel filter( if there is one). Drain oil and refill with fresh oil.

thanks for the quick replies....
OK, the float is definitely not "gas-logged", I can tell it has no gas in it.

The float moves freely, I removed the retaining pin and had it off to clean it ( the pin that is, float was clean)...

Bowl had a little surface rust in it that I cleaned out...

009to090, the metering needle is what the float drives up into the carb? If so that has the red viton (thanks robert) coating on it, maybe that coating is not sealing any longer as suggested.

I'll do the solvent soaking and rebuild on the carb as you guys are suggesting. edited to ask......Is the metering needle part of the rebuild kit?

One thing that bugs me, why isn't there any fuel in the bowl at all? It seems there should be some in there that is below the level of the needle. In the first tear down, I had the bowl off to clean it up and check that the float was free then put it back together. Drained the crankcase, didn't put any oil in yet, put some fuel in the tank, turned on fuel switch and opened fuel line valve. I didn't try to run it at all, waited about 1/2 hour and took off the oil fill plug and the gas was in there again. Took off the bowl and there was no gas in it at all. That is why I was thinking the fuel is going from the tank fuel line to what is labeled as the fuel pump on the engine diagram and then into the engine without going through the bowl or carb.

titleist1 wrote:009to090, the metering needle is what the float drives up into the carb? edited to ask......Is the metering needle part of the rebuild kit?

One thing that bugs me, why isn't there any fuel in the bowl at all? .

Yes to first two questions... and don't soak any of the rubber or plastic parts in the solvent. Best to use Mineral Spirits, as its not as harsh as Carb Cleaner....

Possibly, the bowl was emptied due to siphon action. Just a guess.....

It sounds like the pump failed and is pumping the gas directly into the crankcase. Pull the pump with all hoses attached and actuate it by hand. If your hands get covered with gas, that's it.

coaledsweat wrote:It sounds like the pump failed and is pumping the gas directly into the crankcase. Pull the pump with all hoses attached and actuate it by hand. If your hands get covered with gas, that's it.

how do you actuate the pump? it is a plastic rectangle that has three fuel lines connected to it. One from the tank, one to the carb and one to the engine. I was going to link to the parts diagram that shows it, but my link to that page expired, its asking for a dealer userid and password and I can't find the link I used to get to that page. If I find my way back there, I'll post it.

titleist1 wrote:

coaledsweat wrote:It sounds like the pump failed and is pumping the gas directly into the crankcase. Pull the pump with all hoses attached and actuate it by hand. If your hands get covered with gas, that's it.

how do you actuate the pump? it is a plastic rectangle that has three fuel lines connected to it. One from the tank, one to the carb and one to the engine. I was going to link to the parts diagram that shows it, but my link to that page expired, its asking for a dealer userid and password and I can't find the link I used to get to that page. If I find my way back there, I'll post it.

Yes, thats true, possibly pump. Yes, theres an input, output, and Impulse lines running into the little square box. They are cheap to replace, $20 - $25.

Sounds to me like your tube that comes from the cranckcase, the one that pulses the fuel pump is not in the right position. It is letting the gas slide right into the crankcase. Swithch the line that comes from the carb with the one that goes to the crank

Ok, so a rebuild kit and a fuel pump replacement are in my future.

I will just plan on doing both since I am now a girlie man and need my 13 yer old genny to be dependable to keep my stoker running!

Just clean it all out good with brake cleaner & follow w compressed air through the gas line. No need to buy anything. It's just dirty. Happens all the time when they sit. If it drips, a thin bead of RTV will fix that. Cheap & easy.

SMITTY wrote:Just clean it all out good with brake cleaner & follow w compressed air through the gas line. No need to buy anything. It's just dirty. Happens all the time when they sit. If it drips, a thin bead of RTV will fix that. Cheap & easy.

Smitty...you talking about the fuel pump?