Stalling
 

I have a 1998 5.7 thunderbolt engine after four to five mins of runing down lake at half throttle it stalls at that point i back of throttle off and it idles fine get back in throttle and pops back thru carb and i idle home out of gear runs and revs up cranks up fine happens under load. Also have noticed when use trim it happens Any ideas

Stalling
 

On Sat, 10 Jun 2017 23:16:55 -0700 (PDT), wrote:

I have a 1998 5.7 thunderbolt engine after four to five mins of runing down lake at half throttle it stalls at that point i back of throttle off and it idles fine get back in throttle and pops back thru carb and i idle home out of gear runs and revs up cranks up fine happens under load. Also have noticed when use trim it happens Any ideas

Fuel delivery problem would be my first guess. Replace the filter
elements, check the hoses for collapsed inner liners, maybe a bad fuel
pump?
You can eliminate a lot of the fuel system by connecting a known good
hose to a portable tank directly to the fuel pump. That can allow you
to isolate the problem to the engine side or the boat side.