yamaha 2004 f40tlrc won't start

[tooner]

engine has been starting hard. used to start by giving it half throttle but would take a while. when it got warm engine would start and run just fine.the longer the boat sat the harder it started. now it won't sart at all. new plugs and fuel filter in. pulled out prime start valve engine will run on high throttle until the float bowls run out. took apart prime start valve took brass valve out with needle i'm told that has bees wax in it.put valve back together put back in motor. piston in valve up in to cap plugged in wires it will idle all day long. but won't throttle up just stalls. took off outlet hose from fuel pump gas shot out three foot so im guessing the fuel pump is good.plugs i pulled out are black. like its running ritch plugs are never wet though. maybee its time to tear carbs apart for a cleaning?

[jb123]

try different tank, hose, ball and gas....see if issue stays or goes.

[tooner]

thanks for the info will try let you know how it goes

[tooner]

drained carbs fuel line and filter. new line. bulb and gas tank stayed the same. just pulled carbs going to clean them.

[tooner]

took apart carbs the only thing that was dirty were the air passage pin holes that are behind the butterflys on the intake side of the carbs. the holes weren't plugged but there was a varnish lookin substance on the top of the carb. there are about ten little pin holes that go to the air screw passage. evedently this must have blocked the air flow because the rest of the inside of the carbs were spotless, no varnish or anything.to see these passages pull the tops of the carbs and its in there. put carbs back on started up just fine.to me it looked like residue from the crankcase vent into the intake caused this problem. i have a 5.3 chevy engine that does the same thing and gums up the butterfly in the throttle body from the pcv vent and needs to be cleaned from time to time. maybe i'm wrong but it didn't look like fuel varnish to me. little tip, pull carbs and air box off in one assembly lot easier.