2004 mercury 90hp stumble

[Xpress04]

​Hey guys, I have a 2004 90hp Mercury. It starts right up and I let it warm up for about 5 min. On the first blast off of the day it stumbles and struggles to get on plane. After that it holeshots perfectly all day. It always has trouble with the first blast off then no problems after that. Any ideas? Thanks

[JOE54]

pumping bulb first ???

[Xpress04]

Yep! I pump it up and it it starts right up. I idle out of the no wake zone for 5 min and it just stumbles and slowly gains speed until on plane. After that not problems all day. Boat comes out the hole great, it’s just the first blast off of the day that it does it.

[Xpress04]

It’s almost as if the carbs get loaded up while the motor is tilted while trailering and it takes the first blast off to get them cleared and running good. Runs flawlessly after that first crappy take off.

[JOE54]

does it smoke real bad when first started???/ possible oil check valve letting oil into fuel line, ,stuck open, floats may need adjustments also

[Xpress04]

Thanks for the input. No it doesn’t smoke that much. I have done a little research and I’m thinking it may be that when I pump the bulb that fuel isn’t making it all the way to the top carb to fully fill the bowl. So it runs but takes some laggy throttle to get it there and when it does it takes off. Then it stays primed for the day so that’s why there is no more problem.

[JOE54]

if you pump bulb firm it should fill carb bowl