Air into engine is 130-150 deg
 

Have been working on a few issues and took the time to put a remote thermostat right next to the flame arrestor on my 292. I was surprised, that even after 15 minutes or so at 3500-4000 rpm of cruising that the temps just stayed around 140. Did dip to as low as 135, and as high as 150. 165 after shutting the engines off and letting it sit. It was hot today on Cumberland...maybe low 90s.

Engines are 377 mag...or 6.2 320 hp. They have seacore cooling...which works fine, and also cats. All air comes in from side ports through tubing to the bottom of the bilge. For sure this is to help get fumes out, as well as make sure any water goes directly into the bilge.

I would have thought that after a few minutes that the inlet temps would drop to something around 100 deg. I guess all the air passing over the cats coming up from the bilge just heats it up. Not the beast way to have the intake right on top of the engine and then add air that heats up before it even can get to the intake.

Any ideas on how to improve this....or is it expected.

Thanks.

I've checked mine and they dropped to 4-5* over ambient within 5 minutes at cruise. Seems like you might need more air. Or your vent exits could be relocated with hose to be closer to the aresstor

Plain and simple YOU NEED MORE AIR coming into the engine compartment. My SCARAB had the same problem. I had to crack the engine cover for best performance at cruise and WOT.

More vents. Add a couple with grab handle vents on the transom also if you don't already. Ol lady might not like it but install some hatch scoops. My project I got as much air going in as well as out as possible. Double up on the side ones also. Makes a big difference.