overheating

[245 LIMITED]

hey a local guy came to me and asked for advise on a problem but i couldnt answer......he has a new 460 ford in a 21 ft boat with a panther jet on it. says when running all is perfect but as soon as shuts engine down temp shoots to 250 deg . once restarted coold immedialy back down .... dont sound normal to me. said has a 3/4 in line comming in and 2 3/4 lines out ...one on each exhaust log.... any ideas

[SmokinLowriderSS]

Man, that's weird, shouldn't happen. Only thing I can imagine is where is the temp sender located at? If it in (for whatever silly reason) in a line near a log exh. manifold, I can see this happening, and it would not be indicative of engine temp. The logs can heat up a good bit at idle and I can see them cooking the water like this. If the sender is in the block (or intake manifold like mine is), I am as confused as you. :cry: