VP 5.0 GI Acceleration Problem, Surging

[Monterey 5.0 GI]

Hello everyone, need some help- so I'm asking the experts. Have a 2001 Monterey with the VP 5.0 GI, bought it used sight unseen. Wouldn't stay running- Installed a new fuel pump assembly- fires right up and runs perfect out of the water. So I put it in the water, idles great, hit the throttle and get full power get to 40-45 mph for a minute-then it just dies, after it stops the engine surges for no reason, and there is a loud hiss noise . If I turn off the boat for a little, starts right up- and idles fine. I can go around the lake at 5mph all day, but as soon as it gets under throttle for little while- it does the same thing.

The old filter and pump assembly did not have the black paint flakes in the gas as mentioned in other threads. No milk shake in the oil, cleaned the intake as well. the lower bellow is cracked in half, but I have read that's not a big deal.

Any help or suggestions would be great- Don't want to have to take it to a mechanic unless I have too. Thanks for your time!

 

[kirkll]

Well I’m not an expert, but who ever told you that having cracked bellows is not a big deal has given you bad info. I’d seriously think of having that taken care of before your boat sinks or the water causes more damage. Those bellows are there for a reason.