I have hot spots in one of my CMI(?) headers on my HP500EFI where the chrome has discolored. My impeller failed about a year ago and I replaced it on the dock. When I returned from vacation I had the motor backflushed and the ECM checked for any overheating codes. No codes found. Since then the spots appeared and appear to be getting worse. Is it the impeller pieces? Also that same muffler tip looks like it also got really hot and is discolored. All of this seems unlikely since I have never seen my temp gage reach more than 170 deg. F.

Wow 36 views and no replies??????

Ok - does anyone else have any discoloration in their headers? At least let me know that. A simple yes or no will work.

No discolor on my CMI headers. Are you getting or does it appear to have the same amount of water out each exhaust? If not you could have a piece of impeller floating around still.

I am not sure where on the header you see discolor. Maybe that will help. Headers are polished stainless and discolor can be polished off once you find and fix the problem. Suggest you have polishing done unless you are a glutton for punishment. It ain't easy.

Is your 500EFI modified or stock? Does it have a water pump or a crossover?

Stock with a water pump.

Can someone tell me the flow path from the impeller to out the tip. i have had the cooling system flushed twice now. i was thinking about removing the header myself and trying to flush it clean.

I fried an impeller a couple years back and had it changed under warranty. After slightly eratic temps I was glad I pulled the hoses for inspection afterwards. I had chunks of rubber wedged in the power steering cooler AND the oil cooler. I was really surprised that these pieces could travel that far down stream through those small openings.
Bottom line is THEY DID. Pull all of your hoses from the seawater pump to the recirculating pump and to the exhaust.
You may be suprised what you find

Later,
Dave

Thanks everyone!

I guess it stands true:

If you want something done right do it yourself.