GT-40 Hard Starting when warm

Been battling this for a couple of years now. Has been about 3-4 yrs/150 hours years since last full tune-up of plugs, wires cap, rotor, fuel filter, etc. Engine starts 100% perfectly on cold start up.

This issue seems to be getting worse, ie cranking longer before finally catching. Recently it is taking 5-6 or more seconds until finally turning over. I should add that by advancing the throttle on start, it seems to start quicker, not sure what that means being that it's fuel injected?

On a whim, I replaced the TFI with no change. I believe it was last year I replaced the relays, no change. The fuel rail holds 37 lbs for 10 plus minutes when key is in on position. Both the fuel rail and FCC hold 33-34 lbs at idle, and 30-31 lbs at 2K rpm. I cannot seem to recreate the problem on the hose out of the water. 

Anyone have any ideas? Something seems to be getting heat soaked.

Another thing to check would be fuel being sent to the intake manifold from the fuel reservoir at the back of the engine. When its cold, no big deal.....the engine likes extra fuel to start, but not so when its hot.   Follow this link to replumb the line to the intake manifold and see if that solves your problem. Replumbing is reversable if it doesnt solve it.

http://forums.iboats.com/forum/engine-repair-and-maintenance/volvo-penta-i-o-inboard-gas-engines-outdrives/10425897-5-8fsi-fuel-reservoir-modification