Starting stopping engine?

[Willy.Fire]

So after giving the new to me 99 3.0Merc boat a good tune up carbs, water pump impeller, gaskets to fix oil leaks, bilge pump and a few more I finally got it back in the water today and have a few questions on starting and stopping proper procedures. So I ran the boat after oil change in driveway about 4 hours before we took it out so I would think it should start fairly easy but it didn't. I pumped throttle 2 times turned it over for a few seconds pumped a few more times and nothing so I gave it between 3/4 and full throttle cranked it and it fired after about 4-5 seconds. Now after driving it for about 25 minutes decide to turn it off and start it right away and it did. Stop it again and we sat for about 10 minutes go to fire it again and nothing so had to do the full throttle thing again. So my question is this normal and do I just need to become more familiar with the starting procedures? Also when I turn it off it sputters for a few seconds just some times. Is this normal? This is all new to me I have never had and rarely been on any inboards. Thanks

[mmwjr]

I think the first start you flooded the engine as you had recently ran it at home. All you needed to do was turn the key no pumping the throttle. May need a carb rebuild or choke adjustment. That sputtering causes the engine to draw in fuel which will flood it. Have you verified engine timing?

[Willy.Fire]

But after just sitting for 10 minutes when i just turned key without throttle it wouldn't fire until I gave it throttle. So shouldn't do this correct? Carbs were just rebuilt by mechanic and it runs way better. He said timing was good. Ill play around with it today more and see what I come up with.

[mmwjr]

It should restart without playing with it.

Carb may be dripping fuel when shut down.
Bad anti-siphion valve can allow fuel to be sucked out of carb back into gas tank.

[Kevlar7r]

Don't be 100% convinced your Mechanic did a good job. My carbs were rebuilt by National Carburetor. As long as my engines have been run in the last month, they start on 2 cranks, no throttle pumps.

[Baby Blue]

when it won't start after being warmed up remove the flame arrestor and see what position the choke is in. if not fully open loosen the 3 screws on the side and turn it until it's just open.
I'd bet that's the prob.
BB

[Willy.Fire]

thanks after how long running in driveway should I check? Not sure if it will make it the lake again this year I have never looked at any part of the carbs so not really sure what the choke looks like.

[Baby Blue]

I would start it then take off flame arrestor. the choke should slowly open and once at operating temp be fully open. If not loosen the screws on the round cap and rotate it so the choke is open. Sometimes if the engine is warm then you shut off engine for a while and engine is only cool it may be too much choke to start at that temp. again open slightly and see how that does.
BB

[Baby Blue]

this video explains it

https://www.youtube.com/watch?v=gviih8tqKxc

[Willy.Fire]

ok I have a better understanding of how it works now thanks. I will try it this week.