Is my 500 efi done for the year? Got hot and now hard to start.
 

Running back to the ramp to beat the sunset time. Running about 4400 rpm and she just felt sluggish. So not sure I started to back out of it and it just didn't sound right. Than I could actually feel something wasn't right. But all gauges were fine except for 180/190 water temp on the starboard side. So idling the last 1/2 mile back the starboard side died. Port side is fine. Got it home hooked it to the hose and the starboard side is hard to crank and it wont start unless I increase the throttle than it will start but wont idle below 1000 rpm and than it runs rough. No water in the oil and no oil in the water. Pull the plugs and they are black a little wet with fuel. The threads did have a little oil on them. Put a new rotor and cap with new plugs and thermostat on. Back flushed the cooling system and got a little piece of impellor and small piece of some type of plastic ring and three small stones. The engines do have 550 hrs. on them. I was told when I bought the boat last year he had the springs done. But I don't know for sure. I guess at some point in time I will pull the valve covers. Any thoughts?

I'd pull the plugs and run compression on them real quick. Even if only by a finger over the hole. Help see if there is a major issue. Of the valve covers are easy then by all means check your valve train. Good luck and I hope it's something simple, but something was causing it to run warm...

Head gaskets are gone.

He said no water in oil so probably not head gasket imo

Seeing as 502 blocks get very hot between the cylinders because there is no water there and they are very thin I would bet money at a minimum the gaskets are gone between the cylinders. Hopefully the deck isn't burnt as well.

You could be right... Happened to me on a race motor and ran fine 10 laps then started to be sluggish

Its been so stinkin hot here, 112 degs in the polebarn. But I am going to try to do a compression check first thing in the morning.

This is almost the same thing that happened to me a couple weeks ago.
Head gaskets were gone. No water in oil on mine either.
Compression test and leak test will tell you for sure.

After a compression test, check fuel pressure had 500efi that would start the same way with two different problems. First time it was a fuel pressure regulator, second time it was the computer. Both times after starting it would run at idle but coughed a sputtered a lot.

1st cylinder 150 psi, 2nd-45 psi 3rd and 4th-0 psi, 10 psi with a couple squirts of oil. I finished welding up my second outdrive stand last night. So I am pulling the motors this weekend.