96 Johnson 112 V4 spl bogging down when given throttle.

[BostonDave]

1996 johnson 112 v4
When I start up the boat and put it in gear, if I give it full throttle, it bogs down and shut off I can only go about 4-5 mph however if I start the boat in neutral and have a higher RPMs if I shift it into gear and can now pick up speed without the motor bogging down. Does anyone have any ideas on what this could be?

 

[racerone]

Some inspection needs to be done.----A compression test is first.

 

[havoc_squad]

Sounds like the transition between idle and full throttle is almost non-existent on the carb(s). Either something is clogged up or they aren't jetted to match the cylinders if they were oversized.

I would have liked to have heard how that idle sounded under load at 800 rpms, but I'm sure the compression test numbers will probably answer that.