ok , yes my first thought was regulator too but figured I'd ask the question about codes first. And this is true, no fuel should be going to the mixer till the engine is starting.
I suppose you could pull the fuel line off the mixer and then turn the key on to see how much is actually coming through and if it continues to when you try to start the engine. This would verify the flooding condition.
Only reason i say to do this is because these regulators are kind of expensive.
Found a service gram hyster had put out in 2009 about new diaphragm kits, seal kits and complete regulators for these aisan units. seal kit# 1479530, diaphragm kit # 1479531 and regulator # 1594144.

good luck