Hello all, first post for me.* I'm working on a 36' International with twin Ford Lehman 80s.*** We weren't getting much water from the starboard exhaust, so after checking the strainer we opened up the sea water pump and found a damaged impeller.* After replacing it, we checked for impeller pieces in the rest of the system.* Salt was caked very heavy on both inlet and outlet sides of the heat exchanger for the engine water cooling system.* Maybe meaning there's been low flow for a while?*
After getting out as much debris as we could find, we started it up and initially got good flow.* Then at higher rpm (1800) it would start to heat up.* It would cool off at 1200 or so.* Back to the dock, checked the intake, did find some sea growth and cleaned it all out.* Rechecked the strainer, found some shellfish, cleaned out.* At this point, I was sure flow would be restored, but unfortunately was disappointed.** I opened both sides of the transmission and engine cooling water heat exchangers, both still look good.* The oil cooling heat exchanger is hard to get to, but its up stream of the seawater pump and I think flow is fine there.*
The seawater pump is Jabsco.* I've seen in other threads that a change to a Johnson is recommended.* With the cover to the pump off, and turning over the engine with the stop button depressed, the impeller does turn and is still undamaged.* There's around 2500 hours on this engine.
So, my question is, Is it possible the pump gearing is slightly damaged and thus causing low flow?* Or is it more likely one of the heat exchangers is internally clogged?* Any suggestions for further troubleshooting?
Thanks in advance for any replies!
After getting out as much debris as we could find, we started it up and initially got good flow.* Then at higher rpm (1800) it would start to heat up.* It would cool off at 1200 or so.* Back to the dock, checked the intake, did find some sea growth and cleaned it all out.* Rechecked the strainer, found some shellfish, cleaned out.* At this point, I was sure flow would be restored, but unfortunately was disappointed.** I opened both sides of the transmission and engine cooling water heat exchangers, both still look good.* The oil cooling heat exchanger is hard to get to, but its up stream of the seawater pump and I think flow is fine there.*
The seawater pump is Jabsco.* I've seen in other threads that a change to a Johnson is recommended.* With the cover to the pump off, and turning over the engine with the stop button depressed, the impeller does turn and is still undamaged.* There's around 2500 hours on this engine.
So, my question is, Is it possible the pump gearing is slightly damaged and thus causing low flow?* Or is it more likely one of the heat exchangers is internally clogged?* Any suggestions for further troubleshooting?
Thanks in advance for any replies!