Thought I'd post my experience and ask for comments to see if I diagnosed and fixed this correctly.
twin BF250s, 2 1/2 years old, 260 hours, had 200 hour service 4 months ago.
MFD and gauge always read the same for both engines. At start and then through idle they tracked the same. At 4800 rpm temp was 205. During 200 hour service I asked about this and the tech said he'd check. He reported back that the temp was 160F and in spec.
So three months later and 30 hours run time mostly poking around the indian river, I noticed the port engine temp gauge was 10-15 degrees below the starboard. Consistent after idle and warm up. 10 degrees below cruise speed and 15 degrees once on plane and running for a few minutes. Only on one run did the port temp come back into line with the starboard. Then next time we went out the temp dropped back down.
This engine had an on and off again partially clogged pee tube that I regularly cleared with 100# test pushed into the pee tube. This usually fixed the problem. but not this time. Even after cleaning it the stream was not quite as strong as the starboard engine. Same results when flushing the engines via the hose connection. definitely a weaker pea stream from port.
First i checked the two water jacket sensor connections. They were clean and seemed to connect correctly.
Diagnosis: Started with a cold engine. Eventually I disconnected the two thermostat water hoses from their respective water jackets and turned the hoses up so the openings faced up. I filled each with fresh water. Looking at the engine from the front, the right side just took all of the water i could pour in. The left side filled with about half a bottle of water. So I reasoned the right side thermostat was stuck.
Once opened up I noticed that first, the right side thermostat screws had some white powder corrosion on the bolt threads 1" up from the bottom of the two long bolts. So no antiseize on the bolts during assembly??? next the right side thermostat was stuck open. due to brown and green corrosion.
Replaced both thermostats, used anti seize on all bolts and spraying CRD heavy on all bolt heads. reassembled, started it up a the pee stream is strong. Let engine idle and brought up to 2000 for 10 min. No leaks and temp rose to 160. Have not been out so I'll check and update after I run on plane.
I have photos but could not get the system to accept the uploaded files. Kept getting a "!" after each upload.
twin BF250s, 2 1/2 years old, 260 hours, had 200 hour service 4 months ago.
MFD and gauge always read the same for both engines. At start and then through idle they tracked the same. At 4800 rpm temp was 205. During 200 hour service I asked about this and the tech said he'd check. He reported back that the temp was 160F and in spec.
So three months later and 30 hours run time mostly poking around the indian river, I noticed the port engine temp gauge was 10-15 degrees below the starboard. Consistent after idle and warm up. 10 degrees below cruise speed and 15 degrees once on plane and running for a few minutes. Only on one run did the port temp come back into line with the starboard. Then next time we went out the temp dropped back down.
This engine had an on and off again partially clogged pee tube that I regularly cleared with 100# test pushed into the pee tube. This usually fixed the problem. but not this time. Even after cleaning it the stream was not quite as strong as the starboard engine. Same results when flushing the engines via the hose connection. definitely a weaker pea stream from port.
First i checked the two water jacket sensor connections. They were clean and seemed to connect correctly.
Diagnosis: Started with a cold engine. Eventually I disconnected the two thermostat water hoses from their respective water jackets and turned the hoses up so the openings faced up. I filled each with fresh water. Looking at the engine from the front, the right side just took all of the water i could pour in. The left side filled with about half a bottle of water. So I reasoned the right side thermostat was stuck.
Once opened up I noticed that first, the right side thermostat screws had some white powder corrosion on the bolt threads 1" up from the bottom of the two long bolts. So no antiseize on the bolts during assembly??? next the right side thermostat was stuck open. due to brown and green corrosion.
Replaced both thermostats, used anti seize on all bolts and spraying CRD heavy on all bolt heads. reassembled, started it up a the pee stream is strong. Let engine idle and brought up to 2000 for 10 min. No leaks and temp rose to 160. Have not been out so I'll check and update after I run on plane.
I have photos but could not get the system to accept the uploaded files. Kept getting a "!" after each upload.