Grasshopper 721 and need some ideas

BugsBunny · Jul 12, 2011

Have a Grasshopper 721 gas we picked up recently, it has a stumble under load (cutting grass) once up to op temp, has an inline filter which has been replaced along with the carb being drained several times.

We cut about 6 acres so far with it at different times it has never stalled just a stumble enough to kick the pto out, followed by resuming to run properly.

My son seems to think with the choke on just a tad it does not do it = lean condition, yep checked the carb to motor gaskets & carb is tight as well.

Think this has a Koehler in it with some electric switch in the carb? we have a craftsman lawn mower w/ similar switch / selonoid that surges very similar.

What should I look at as the culprit on this grasshopper?

Thanks Gents

Bob · Jul 12, 2011

Since the PTO drops out, its sounds like an electrical problem with either the main power circuitry or "operator presence" system?

joe csuti · Jul 12, 2011

I agree with Bob,your problem is probably electrial,looking at wiring diag online for a 721K there appears to be a circuit board that flasher mounted on,if this is a pc type board(foil circuit on board)this may be your trouble point,you might have broken strip(s)on board or bad connection(s) to connectors on board as most of wiring for safety sw's appears to run thru board,you'll probably have to spend time with same trying to locate/isolate problem & may also need a service manual,if you don't have owners manual or do have manual & no wiring diag in same do a goggle search for grasshopper 721+parts,click on link to the mower shop(1st or 2nd link)select 721K from mod list click on any yr for same,look at wiring diag,you'll see board I'm talking about with flasher(8)on it.

BugsBunny · Jul 12, 2011

(quoted from post at 12:45:24 07/12/11) I agree with Bob,your problem is probably electrial,looking at wiring diag online for a 721K there appears to be a circuit board that flasher mounted on,if this is a pc type board(foil circuit on board)this may be your trouble point,you might have broken strip(s)on board or bad connection(s) to connectors on board as most of wiring for safety sw's appears to run thru board,you'll probably have to spend time with same trying to locate/isolate problem & may also need a service manual,if you don't have owners manual or do have manual & no wiring diag in same do a goggle search for grasshopper 721+parts,click on link to the mower shop(1st or 2nd link)select 721K from mod list click on any yr for same,look at wiring diag,you'll see board I'm talking about with flasher(8)on it.

Looked it over & found a black wire hanging that appears the come from the carb and looks to have been ground to the block - looks like the bolt vibrated out & gone.

Seems like there had been two bolts holding a bracket on the motor at one time just above the distributor - gone, its one of those bolts this ground would go to, however not in the wiring schematics for 1989.

Once I find a screw to ground that wire in the morning, will be ready for a test run.

Thanks a bunch gents

Grasshopper 721 and need some ideas

BugsBunny

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Bob

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joe csuti

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BugsBunny

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