I have a 2001 Mercury 175 EFI. It recently got new plugs, filter, and throttle cable adjustment. The motor runs wonderfully. The first start of the day is on the first crank. Now that the weather has turned cooler, I can run it for a while with a decent warm up, then stop at a spot to fish a while (hour or so). When I go to restart the motor, title crank and crank, but has difficulty turning over. I can trim all the way up and give it gas though the foot throttle and it starts better. I'll burn off the excess gas and it riluns fine after another warm-up. It smells like the engine is flooding on the initial crank that doesn't turn over.

Any thoughts?

Compression is good, bulb is tight when I think to check it, no engine faults (at last check).

It may be oiling too much

When was the last time you had your injectors or VST serviced?

Also, check all the bleed lines in the plenum area to make sure they are attached and/or not cracked or broken.


Gman

Check and clean all of the grounds and wire connections at the controller on top of the motor and at the temp sensor on the port cylinder head.

Good advice. I am thinking I am having a minor fuel supply issue. When I go to crank it after sitting and fishing if it doesn't start right up, it will sputter pence, and then won't fire until I crank for a while. I checked the fuel bulb one of these times and it was a little loose. If it has been sitting for more than an hour (but not 4-5), I can do a couple of pumps on the bulb before it gets really firm. It will crank right up like when I first launch.

I will take a look at some of these suggestions, it I think fuel is draining out of the system, and it is taking the cranking to re-prime.

Pull the cover and pump the bulb... see if any fuel is leaking around the bowls.. I had that issue..

The mechanical fuel pump may be allowing the fuel to drain out of the vst tank along with the pump. In short: ya just don't have the fuel volumn to pressurize the fuel system for it to start. That's why if you reprime the engine prior to starting, it fires right up.