Problem solved, maybe!

[Z518 Comanche]

I had posted earlier about problems i was having with my 06 V-max 150 (carbed). Between 4000 and 5800 rpm, it would lose power and pick back up. Bottom end was normal, very strong. It was driving me nuts. I had changed 10 micron filter, fuel pumps and primer bulb. It still did it. I winterized my boat saturday and figured during the winter I would change all the fuel lines out. I pulled the fuel line off the port tank and unscrewed the 90 deg fitting out of the top of the tank, the suction hose inside the tank had a 1/2 inch split in it. Primer bulb primes up right now. Hopefully problem solved. won't be able to find out until spring

[Rich Z]

Hope that was the problem but typically from what you have described, that is a carb problem and they may need to be removed from the motor and cleaned.

[Charlie206]

If the split was above the top of the fuel level, it would cause a problem. If it was immersed in fuel it shouldn't make any difference.
As the fuel level dropped below the split the engine would start sucking air.

[Z518 Comanche]

The split was at the top, where it slides onto the fitting. I am going to check my carbs during the wintr also. I am considering putting a Phase I kit on it anyway, so the carbs will have to be re-jetted. Thanks