You might want to post the model number of the engine since there is more than one 17.5 hp B&S engine.

Walt Conner

OK got it here:

Model 42A707

Type 2653 E1

I took the air cleaner apart, the filter is clean almost brand new.

Looking at the carb it doesn't have a air/fuel mixture screw, that is the first thing I thought of. I did notice the throttle linkage doesn't seem to sit exactly on the idle speed screw, but the motor runs strong and doesn't appear to be idling too high.

There is still some fuel in the carb when I open the choke, and the plate inside the carb isn't returning all the way closed. Does that help?

The carb complete certainly isn't cheap for these. Usually it is a matter of removing the 4 body screws, checking the float for saturation and replacing the float valve and body gasket-along with a little clean up. That is if you are correct in the assumption that it is flooding. The seat kit is available for these typically as well.

I would try shutting the gas off 15 seconds or so before shutting the engine off and see if that makes a difference. IF there is no gas line shut off, I would add one but you can clamp the rubber gas line to shut off gas to try.

Does the gs line happen to run thru the cooling shroud?

Walt Conner

OP - reading your initial post, I get the impression that you are attempting to start a warm engine using full choke - which can account for the flooding that you are experiencing.

Try simply cracking the throttle around 1/2 way when doing a warm restart. reserve the choking for cold starts, like when the machine has sat in the garage overnite and completely cooled off.
If I misinterpreted your post, pls disregard this reply.

Yeah, does sound like that, good catch.

Walt Conner

On initial start I use full choke, then as soon as the motor starts I open it fully. On a hot soak I don't choke at all.

Walt, you're correct on the gas line routing. No fuel line shutoff on it.

Now that I think of it, there's a common thread.

Both times I've used the mower since acquiring it, I've gotten up out of the seat with the engine running at "Fast" speed to dump the bags. The safety switch then shuts the mower off. Should I be manually shutting the mower off first by moving the lever to the full slow/stop position?

You should disengage the mower blades & set park brake.