Port engine starting slow when hot

[Good News]

My 454xls always start but when hot starboard engine starts instantly with no throttle. Port engine takes some winding to start. Both engines had complete tune ups last summer and run well. I am wondering if it could be anti-syphon valve leaking back and where is it located? They have electric fuel pumps. Any ideas.

[waybomb]

Leaking injector(s) causing it to flood?

[g36]

Anti siphon valves are located on top of the fuel tank right where the fuel line connects

[Good News]

My engines are still carbarated so that would leave out lnjector leaking but thanks for suggestion. I am going to check anti-siphon valve as soon as I can now I knowwhere to look. Thanks for replies.

[tomschauer]

With electric fuel pumps, even if the anti siphon valve were failed open the float bowl would have enough fuel to start the engine and keep it running for the second it took for the fuel pump to deliver fuel to the carb.
You mention this is a "hot" engine problem. Does it start quickly when cold?

[bud37]

Is the fuel line on that engine getting warmer than the other??, maybe a little vapour lock, not uncommon....you can insulate the fuel line if that is the case.

[tomschauer]

Most likely a Quadrajet carb. If hard starting cold and hot, fuel bowl plugs leaking into engine. Remove, buy a rebuild kit and add epoxy to the plugs to prevent leak down. If only when hot, could be leaking at metering rods, or the carb base is warping when hot and letting air in at the base gasket. Get a rebuild kit and a base gasket with spacers to keep from warping the carb base.
These are good carbs when set up properly. If you don't know how to set up the metering rods, have someone else do the rebuild. Unless you know a good marine mechanic, who knows q jets, take it to a speed shop.

[tomschauer]

I am a bit older these days and not on top of all the mechanical issues like when I was younger, but it still comes back to me with some thought.
If the engine has starting problems, hot or cold, remove the air cleaner look into the carb and have someone open the throttle lever (engine not running). You should see a shot of fuel from the accelerator pump into the primaries as the throttle is opened. If you see this, the carb is not leaking down.
If you have fuel from the accelerator pump and only have a hot start issue you MAY have an HEI ignition module issue. The good thing is this is a quick and relatively easy and inexpensive fix.

Sorry for all the posts, just trying to help.

[waybomb]

When it does start after bring hot, did it run rough for a bit or smooth?