Hard starting boat

by JG
(conroe, texas)

I've got an 19ft 2004 Chaparral that is giving me trouble starting. I took it to a shop and they rebuilt the carb, cleaned out the jets, replaced the fuel filter, emptied the fuel tank. After reassembly, they tested it by running their tank directly to the new filter. Boat fired right up. I took it home, put fresh gas in the tank, and couldn't get it to start. After 30 minutes of trying took it back to the shop. After at least 30 minutes of priming and adjusting the carb he got it running. We took it out for the day, no problem. Two weeks later, took it back out and the same thing happened. This time we were on the water and couldn't get it started out of the launch. I pulled it out, took it home, pulled the air filter, dropped a little fuel directly into the carb and it started up no problem. I brought it home and a few days later same exact issue. I took it back to the shop this past Wed. He once again hooked it up to his tank and it fired up immediately. According to his diagnosis there isn't anything wrong with the carb, it's getting fuel, etc. The issue must be either a clogged fuel tank or a clogged fuel line. So yesterday I pulled the tank, replaced the anti-siphon valve, blew out the tank with compressed air, added fresh fuel. I tested the tank with a manual siphon and after a minute or so of priming fuel was running out fine. I then blew out the fuel line with compressed air, which did sound as though it was clogged. Once done I reinstalled the tank, etc, primed it up for a minute, and it started right up. I let it run a while, shut it down, and checked again a few hours later. All seemed fine. Then this morning, I tried again to start it and nothing. The same exact issue. I'm completely at a loss now and don't know what else to look for.