Hey Herb- What COLOR is your Kohler engine?
If it's BLACK, then go to KohlerEngines.com, and download the service-manual for the K91-thru-K341 engine, then turn to page 6.5.
The original engine to come with your 149 SHOULD'VE been IH yellow, while service-replacement-engines were typically Kohler black. My 109 had a service-replacement K241 which was extra-grumpy about starting, 'till I saw that note...
Apparently, when they did some design changes, it had a side-effect on the choke operation. Originally, the choke-plate has a pair of 3/16ths holes drilled through it for 'choke relief'... but that isn't enough relief to keep the engine from flooding right-quick, so they advise that one of these holes get drilled out to 11/32nds...
If lack of sufficient relief is the issue, then one way to solve it, is to not pull the choke out all-the-way. I found that I could start the engine with no choke, pull it all the way out for just one rollover, then push it back in to get a fire going... so I re-adjusted my choke cable so that when pulled out all-the-way, the choke would only be partially applied. The side-effect is that now when I push the choke knob it, it stops BEFORE getting all-the-way in place. Of course, I could drill mine, but I'm too darned busy doing other things...
As for hydro 'creep'... the linkage on the side of the hydro is affixed using two bolts on the transaxle that had long slots for adjusting vertical position of one plate... this changed the 'forced center' lcation of the transaxle swashplate. A little 'creep' isn't unusual. I defeat it on my 109 simply by lifting up on the 'release handle'... might not be a good thing to do, especially without seeing a hydro unit's internal workings or schematic diagram... can't tell 'ya for sure...