My 35 Vanguard GDSD starts just fine from a cold start and runs great until the motor heats up and then it seems to lose power (harder to get on plane) and if I kill it while hot and let it set for a few minutes it is really hard to start (have to let the starter turn the engine for way too long and mess with the choke and feather the throttle). Also, it will not idle at all with the prop in the water, always dies if I let off the gas. I just replaced the carb thinking that would fix the prob but it didn't. It does have close to 400hrs and completely stock. Any engines gurus have any ideas or pointers for me?? Thanks.

With that many hours, have you ever had the valve lash checked and reset?

Vapor Lock?

Running lean?
Just my thoughts.

I'd start with valve lash and fresh plugs with the right gap. If that doesn't improve it, I'd probably check compression.

Probably a couple of Cheshire cats in there. Leak down test.

I would put money on daylight around the valve seats.

Anyone know of anybody in the DFW (Wylie, Tx) area that could check it out for me and do the repairs? I have tried a couple small engine shops around but felt like I knew more about the engine than they did (which isn't much).

Deadbird8, shoot him a PM

And if he isnt't interested, will c out towards longview is the next closest guy i would trust.

Yea, you're another 4 hours past will. You'd be my next stop after that.