Fixed my lack of steering with a voltage regulator
Thanks to everyone for posting!
Lost steering response on my SST-16, forward and reverse, due to a bad voltage regulator. This is a Briggs & Stratton part (by the way, B&S no. 394890, JD No. LG691185 (which my local dealer had) but note that the JD website says that "LB691185 has been replaced by MIU12514" $92 on 28 August 2009. Ebay for $50.
If you're getting a steering problem concurrent with a dead battery, I'd consider testing and/or just replacing the voltage regulator. I suspect it's a chronic problem, because my JD dealer's parts mgr. said he had them in stock before I even finished reading him the part number.
5 minute job, the voltage regulator is bolted to the right side of the engine shroud, just behind the right cylinder. It's a square aluminum block, with a pair of yellow wires and one red wire coming out of a block of expoxy potting compound.
My battery was intermittently going dead, I thought it might have been the ignition switch not going completely off. I started taking the key out, to make sure my knee wasn't turning it partially on when I climbed out of the seat. This 'seemed' (ha ha) to work until a few days ago.
It wouldn't start, so I had to jump start it, and after about 45 minutes of mowing the steering stopped responding. I let it sit for a few minutes with the engine running, and the steering came back to life for about 60 seconds, enough time to get it in the shed, but not to park it.
I went on line and found this forum, and saw voltage regulator, vacuum leak, or bad switches as possible culprits. Since I had the battery charging problem, I got the voltage regulator first. The steering has to have electricity to actuate the hydraulic system.
This morning I replaced the regulator, hooked up a 4 amp charger to the battery, and let it sit for about 4 hours. Then I tried it, it started right up, and steering was as good as new.
Hope this helps someone else out.