Seems counter intuitive WOT when flooded

[Mark Tindal]

Hi,

I tried to go boating for a few hours yesterday, I arrived and started the Mercruiser V8 by bringing her out of gear and pumping a couple of times to mid point and then back to about 1/4 throttle. I turned the key and she started immediately and purred like a lovely angry tiger.

I left things in idle throttle for about 5 mins then turned off while I sorted something in the cabin.

15 mins later, I done exactly the same thing again and no spark, not even a cough of a start. On the second occasion I seem to recall pumping a little too much before starting.

My mistake (and I'd love opinions) was that I really didn't need to do ANY pumping on the second start so I think I flooded the carb/sparks or what not.

I left it 10 mins and nothing, half hour and nothing. I then went home.

The question...
In reading forums and watching videos online, I'm told that I should (after the half hour) tried pushing the throttle all the way to full (gear not engaged obviously) and turning the key a few times.

I am abolsutely not a mechanic so I'm confused. Why would I take an engine that is flooded with Gas and push even more at high speed into it. Can someone please explain it to me, I'm not an idiot but this just didn't seem to make sense.

 

[MonacoMike]

You are actually giving it more air to counter all that gas that got there from pumping, the opposite of choke which is more gas than air.

MM

 

[Espos4]

What Mike said above.

On a carb application, you’ll see that full throttle will move the choke plate to allow more air to enter, reducing the speed of the incoming air, which draws less fuel from the carburetor bowl. This is done through the magic of mechanical engineering.

On a fuel injected application, the ecm sees the throttle has been opened from the signal it gets from the throttle position sensor.

As a result, the ecm doesn’t fire the fuel injectors when you engage the stater. This is the magic of electrical engineering.

 

[boatman37]

Yep, what they said. When you go to full throttle you are actually squirting more fuel in, which doesn't help but now the throttle blades are all the way open, letting more air in to get the air/fuel ratio closer to normal. When you do go to full throttle you only get an initial shot of fuel. Once the throttle level stops moving no more fuel is coming in if it isn't running.

On my 1986 Sundancer on my initial cold start I pumped the throttle to about 2/3s then pulled it back a little to start. Once my engine was warm I would start it without touching the throttle.