Riser Temperature Difference FWC 454XLbs

"Symptoms: At idle speed belo

"Symptoms: At idle speed below 1200 RPM, port engine runs 145 and starboard runs 120 on the bridge gauges. At cruise RPM both engines run exactly 145-150F. At idle speed I can measure a 40 degree temperature differential at the riser and exhaust bellows with an infrared temp gauge. At cruise both engines at the same location are within 5 degrees of each other. Should I be concerned and start looking at removing the riser and/or U-Cooler for cleaning or just monitor further. Engines are installed in a 1993 Silverton ACMY with 800 hours."

Starboard may have a thermosta

Starboard may have a thermostat not closing completely.

"One of mine does that nonsens

"One of mine does that nonsense as well. 'Long as it finally comes up to temperature, I let it play its little games.

Jeff"

I am assuming these are raw wa

I am assuming these are raw water cooled? If so I would just monitor since temp is staying within limits.

"Could be one of those infamou

"Could be one of those infamous bypass valves isn't closing, too.

what are the specifics on the 40 deg temp delta - high, low, etc?"