i've looked through the threads and can't find anything that helps me with this particular problem. I have model TVS90 and it won't start. I've done the following:

1. Checked and got spark.
2. Pulled carb and cleaned it good with cleaner, including clearing holes. Replaced needle and seat (float was OK) as well as gasket on float bowl.
3. Discovered the primer bulb had a hole in the underside, so replaced that as well.

The situation seems to be that the plug is dry as can be, even after priming. I squirted some carb clearner down the air intake, but it still didn't start or even cough.

Short of buying a new mower, anyone have any suggestions for a next step? Thanks in advance.

buy another one and dump the tec........... haha but no, do you have the carb set right, and not that it won't but carb cleaner isn't used to start em, you have to use starting fluid or gas straight down the carb. also the float may have stuck which it does happen sometimes.

A technician suggested using the cleaner--said it would provide a fume that would be enough to test whether the problem is in the carb or not. I'll try squirting a little gas and see what happens. I'm pretty sure there is nothing coming out of the carb though, because the new plug is dry. I'm going to check the choke action as well. Thanks.

After some more effort and pulling the carb again, I haven't made much progress. The engine will start and run for about 5-10 seconds if I either squirt carb cleaner or put a little gas in through the air filter side. Also, pumping the primer bulb doesn't result in gas coming up into the venturi. Clearly, the carb isn't providing gas either from priming or once it's running (briefly). I guess there must be an air leak somewhere resulting in not enough vacuum to pull the gas up? Any next steps? Thanks.

Likely a day late and a dollar short but here's my 2:
Gravity fed (and most pumped) fuel systems require a small vent above the fuel intake. If the vent hole is clogged, or otherwise blocked, fuel will not flow in sufficient quantity. Perhaps obvious but I had to...

good luck

I am having the same trouble today. I have the carb off now for the 2nd cleaning. The Tecumseh manual mentioned checking the air filter. My mower is a 3.5hp craftsman (143.963504 = TVS90-43576M). I bought this thing I think in 1995. The cheapest mower I could buy! It has been reliable until this year.
It will start on half a pull and die after 4-5 seconds.