Gas in the air filter

[JHZR2]

I have a few old snapper mowers, in this case one with a 3.5hp B&S max.

On the front is a panel that holds a pleated paper air filter. I was going to use the mower today (after changing the blade), and had a new AF and pre-filter.

I pulled it and it was essentially saturated with gas. Not dripping, not wet, just obvious from looking at the media. There was no sign of liquid fuel, dampness on the engine shroud, filter cover, carb side, etc. only the media.

It ran well with the new filter and prefilter. If anything I think it’s a tiny bit slow, but I don’t have a tach.

I assume this has something to do with the carb - maybe something that lets fuel vaporize and then condense in the media?

It started first pull after sitting for over a week.

So what is this telling me and what should I do? I usually mow the property I have this mower at with a reel mower, but it gets a lot of leaves which is a pain. With the new hivac blade on this it really suctions and cleans well. So id like to have it tip-top for fall when the leaves start dropping.

Thanks!!

 

[Lubener]

Usually if the mower was tipped on its side or the carb float is sticking will saturate the air filter with gas.

 

[ripcord]

Might have an issue with the float and needle and seat allowing too high a fuel level.

 

[Oro_O]

Might have an issue with the float and needle and seat allowing too high a fuel level.

Very often this. Open the oil fill after it has sat a while and see if it smells of gas, too. Fuel overflowing the bowl will usually leak both into the air filter and into the cylinder (and down).

 

[fantastic]

fuel seeping past the needle, filling up the bowl, then the air filter is soaking up the fuel.

 

[blufeb95]

The mower may have been tipped air filter side down, the float needle may be sticking, it's been over primed on a manual priming unit, also in a more unlikely scenario on a model with a choke is the choke is staying on too long and liquid fuel is running back out the throat of the carb similar to over priming it.

 

[JHZR2]

The mower may have been tipped air filter side down, the float needle may be sticking, it's been over primed on a manual priming unit, also in a more unlikely scenario on a model with a choke is the choke is staying on too long and liquid fuel is running back out the throat of the carb similar to over priming it.

It is manual choke, I can tell if it’s choked versus in “fast” condition because it will bog down a bit when choked and running/warmed up.

I don’t feel that the fast setting is really fast though.

Also, the air filter on this one is on the front of the engine, so I don’t think it has been tipped that way.

 

[mk378]

That is the common "Quantum" series engine. They were made with a lot of different start enrichment systems including manual choke, automatic choke, and primer bulb.

The crankcase vents into the air cleaner housing. The stuff on the filter could partly also be oil from excessive blowby, overfilling the oil or tilting the machine. Most mowers have the engine mounted with the carb on the side, so to tilt the mower to work underneath you'd tilt to the other side. Here it looks likely that gas and oil will run out no matter which side you tilt toward.

 

[mk378]

I don’t feel that the fast setting is really fast though.

Everyone loves to turn up the governor on push mowers but I've found any slightly better cutting performance isn't worth the drastic increase in fuel consumption.

 

[oil pan 4]

Probably a fuel float and needle valve leak issue. I just install a fuel shutoff in the fuel line.

 

[JHZR2]

Probably a fuel float and needle valve leak issue. I just install a fuel shutoff in the fuel line.

There is one in the line. But I’d assume that there is still plenty of fuel in the carb to do this over time?

 

[tnt_motorsports]

my old JD push mower with a B&S would get the air filter wet when I tipped it over to sharpen the blade or change the oil. After learning this, I would always try to keep the air filter on top when tipped. Obviously a little more challenging for you on the front... You could remove the air filter and use a rag.

Just my $0.02

 

[JHZR2]

That is the common "Quantum" series engine. They were made with a lot of different start enrichment systems including manual choke, automatic choke, and primer bulb.

The crankcase vents into the air cleaner housing. The stuff on the filter could partly also be oil from excessive blowby, overfilling the oil or tilting the machine. Most mowers have the engine mounted with the carb on the side, so to tilt the mower to work underneath you'd tilt to the other side. Here it looks likely that gas and oil will run out no matter which side you tilt toward.

I know my other snapper has an auto choke, with the little cover on the carb that the throttle arm boss needs to be set against.

This one it seems to actually choke when I run the throttle control against it.

Looks like the carb can be rebuilt.

I’ve never taken one apart so it’s a good chance.

It could well be oil residue as well on the filter, but it smells strong of gas.

How does one check for blowby on these? Similar to the way you do it on old diesels? Remove the oil filler and see if it puffs up?

The carb is not convenient.

 

[jkasch]

my old JD push mower with a B&S would get the air filter wet when I tipped it over to sharpen the blade or change the oil. After learning this, I would always try to keep the air filter on top when tipped. Obviously a little more challenging for you on the front... You could remove the air filter and use a rag.

Just my $0.02

That's my experience with my 2007 Super Recycler primer bulb B&S Max. Tip it with the air filter down and it gets wet. Tipped the other way, it stays dry. It's on its 16th season and still starts on 1st or 2nd pull. It doesn't surge and the carb has never been off or cleaned. Love that old flathead.

 

[JHZR2]

I did put a new filter and prefilter in there yesterday before mowing. Mower ran the same as before.

I’m assuming I should get a carb refurbishing kit though and do it. Best practice if nothing else…

 

[oil pan 4]

There is one in the line. But I’d assume that there is still plenty of fuel in the carb to do this over time?

I turn the fuel valve off and let them run out of gas. But yeah if someone manually shuts off the engine and then closes the fuel shutoff there's plenty that can leak out.

 

[JHZR2]

I turn the fuel valve off and let them run out of gas. But yeah if someone manually shuts off the engine and then closes the fuel shutoff there's plenty that can leak out.

Thing is, it can’t leak out and up. Do you mean evaporate and recondense somehow in the media?

 

[oil pan 4]

It shouldn't be able to leak up or out but it does.