Toro Super Recycler 6.5 HP B&S Motor - dies

I have been getting my lawn done since i was traveling a lot, and when i finally got chance to mow grass, mower would not start. this is a 5 year old mower, and it was fully serviced in shop 1 year ago (serviceable gaskets replaced, filters, fully checked out)

Estimate it was not used for 6 months. Gasoline was drained, and oil changed before it was left dormant.

Mower would not start at all. Tried starter fluid and could get it to run on starter fluid only - only 4-5 seconds, never consuming actual gasoline. Cleaned spark plug and verified spark is good w multimeter. Removed carb and disassmebled, cleaned w carb cleaner, blew it out w compressed air, re-assembled, made sure needle valve correctly installed, and reinstalled carb on motor. replaced air filter, fuel line (was cracking) and checked that fuel cap is sealing properly. checked electrical contacts of deadman circuit and they were not corroded.

cranking the motor by hand w carb removed you can hear suction from the cylinder through the fuel port, which I take as a good sign that there isnt anything clogged there.

I have re-assembled the mower and am now able to get it to start on starter fluid and then run on gasoline for about 7-8 seconds. it seems to run fine and then abruptly get killed - almost like all gasoline in the carb is being consumed and not being replenished from the tank (yes the tank is full w new gas and the fuel line has been triple checked).

any ideas what I could check next?

description of engine:
this type of B&S motor has no external throttle lever, but does have a metal arm which pivots on a axis at the back of the motor. this arm is linked to the carb via a stiff metal rod. the rod is attached to a black pastic arm on top of the carb, and it in turn opens and closes the carb's valve. Also attached to the carb is a spring mounted to what appears to be a choke lever just above the carb primer bulb on the front of the engine.

a handle lever links by cable to the engine via two arms and a spring. this assembly is linked to the deadman switch. I would think if this is the governor it should be visibly linked to the pivoting metal arm described above, but I do not see any such linkage.

I am unable to locate the engine serial number. the mower is a Toro Super Recycler model 20037 Serial 220010476.

Any advice would be appreciated.

 

Did you pay special attention to the nut that holds the float bowl on? There is a little metering orifice in the center of it that delivers fuel up the nozzle of the carburetor. There is also a hole in the side of this nut that feeds fuel from the bowl to the jet. Make sure that these are open and clean.

Best of Luck...

 

Indeed - this is a brass hexnut with a 3/4 inch head I think. it is clean as a whistle. :-)

 

[h=2]Starts first pull but.....[/h]

Then motor surges and lopes as if it's a fuel supply problem. Eventually stops running. Gas is fresh and I know flow is fine at least to carb side of fuel filter. Air filter was filthy but does same thing regardless if air filter is on or off. Removed carb bowl and shot float w/ carb cleaner. No change. Removed air filter housing and douched all accessible carb parts w/ carb cleaner spray. No joy. Right now I'm just short of removing carb assy from intake manifold. What typically acts as the fuel pump for these mowers? Is it a mechanically driven diaphragm type pump? Possibly hole in diaphragm? Once motor gets up to normal operating temp it runs pretty well but I still sense a stagger. It's a approx 2007 Toro with a 6.5 HP B&S motor. No primer bulb, but never needed one anyway. Would appreciate any help possible. Thanks.

 

Did you check the holes in the nut mentioned?