Old Evinrude

I have a 91 -- 150hp Evinrude start fine and run great setting in the yard, when I get on the water it starts right up but when I go to power up it dies and won't start until I sit ant where from 2 to 10 minutes, then the same thing if I work with it I can usually work through this and I wil run fine for a while. I have checked carbs. And replace the small switch on top of the motor still same problem. Any ideas?

check for air leaks in your fuel line connections, had same problem on an 82 johnson 175.

could be too that the fuel pump diaphram has a hole, pull/clean screens and inspect diaphram.

If you are having to let it set for that long before it will start, it is flooding. First thing I do on these motors is make sure they have the correct Champion spark plugs. Makes all the difference in the world how these motors run.

X2 on plugs, and if its flooding seems like your seat in the carbs aren't sealing.

Checked the carbs, what exactly did you check? Try pumping the primer bulb does it get rock hard or can you force fuel through the carbs? Pull the cover off the carbs, trim it up a bit and watch the carbs for any drips while squeezing the bulb.

Thanks I'll check all these.

We have seen some of the fuel enrichner valve shorted causing it to act like the choke is on.