In the last couple of weeks I have had one issue I've never come across and another I have seen only three times. Both of these incidents are preventable..
Sherwood M-25 Raw Water Pump Seized
I have seen this one happen twice before and, go figure, once with this same crappy Sherwood raw water pump and the other time with a Johnson pump.
In both cases the pumps were allowed to sit for a winter, or longer, with antifreeze left in them. While the Sherwood pumps on the Universal motors are rather horrible, and feature an iron pump body as opposed to proper bronze, the event here could have likely been eliminated. Had a quality antifreeze been used AND the impeller was then removed for winter and the pump left empty, this event likely never would have happened.
On this one the antifreeze used was the cheap Wal*Mart ethyl alcohol blend with no anti-corrosion package. The boat sat for nearly two years until it recently went under contract. I was called in when they could not get it to pump water.
No kidding it would not pump because the RWP shaft completely corroded & froze solid to the pump body. When they cranked the motor over it literally sheared the end of the RWP shaft clean off......
The seller narrowly avoided a repair that could have cost nearly as much as what the boat was selling for, had it been the timing gear driven shaft that had broken or one of the timing gears...
While the gear driven engine shaft is clearly marred and slightly damaged it should still easily drive the new Oberdorfer pump that will be replacing the crappy Sherwood pump.
Had this shaft broken the repair is likely well into the four figure territory!!!
Moral?
#1 Don't use cheap antifreeze
#2 Remove the impeller after winterizing
#3 Get rid of that Sherwood RWP and replace it with a better quality Oberdorfer.
Oberdorfer Rebuild Fail
I was called to this boat for a lack of pumping water & a funny noise. The owner "recently" had the pump rebuilt which really only included the seals to stop sea water from dripping on the engine. D'oh..
Sadly the person rebuilding this pump never fully inspected parts like the cam for signs of corrosion. The threads holding the cam into the pump body literally corroded and rotted away at which point the cam began spinning around the inside of the water pump with the impeller.
Forget a rebuild the pump body is now destroyed and the owner now needed a complete new RWP.. When "rebuilding" something this means "rebuilt" as in every piece that could wear or fail must be fully inspected and or replaced. This cam was totally dezincified and very weak hence the failure of the threads. This owner also has Drive Saver which isolates his engine from the prop shaft zincs meaning his only anodic protection was the teeny tiny HX zinc which was no longer even there... There is good reason the ABYC requires the shaft NOT be isolated from the engine and this is but one of them.
I know the pic does not do the dezincification justice but the coppery color around the screw hole and towards the edges is frail metal due to the zinc being eaten out of it. Any tech, who actually understands marine corrosion, even a little bit, should have spotted this galvanic damage in seconds and replaced that cam as part of the "rebuild"......
Sherwood M-25 Raw Water Pump Seized
I have seen this one happen twice before and, go figure, once with this same crappy Sherwood raw water pump and the other time with a Johnson pump.
In both cases the pumps were allowed to sit for a winter, or longer, with antifreeze left in them. While the Sherwood pumps on the Universal motors are rather horrible, and feature an iron pump body as opposed to proper bronze, the event here could have likely been eliminated. Had a quality antifreeze been used AND the impeller was then removed for winter and the pump left empty, this event likely never would have happened.
On this one the antifreeze used was the cheap Wal*Mart ethyl alcohol blend with no anti-corrosion package. The boat sat for nearly two years until it recently went under contract. I was called in when they could not get it to pump water.
No kidding it would not pump because the RWP shaft completely corroded & froze solid to the pump body. When they cranked the motor over it literally sheared the end of the RWP shaft clean off......
The seller narrowly avoided a repair that could have cost nearly as much as what the boat was selling for, had it been the timing gear driven shaft that had broken or one of the timing gears...
While the gear driven engine shaft is clearly marred and slightly damaged it should still easily drive the new Oberdorfer pump that will be replacing the crappy Sherwood pump.
Had this shaft broken the repair is likely well into the four figure territory!!!
Moral?
#1 Don't use cheap antifreeze
#2 Remove the impeller after winterizing
#3 Get rid of that Sherwood RWP and replace it with a better quality Oberdorfer.
Oberdorfer Rebuild Fail
I was called to this boat for a lack of pumping water & a funny noise. The owner "recently" had the pump rebuilt which really only included the seals to stop sea water from dripping on the engine. D'oh..
Sadly the person rebuilding this pump never fully inspected parts like the cam for signs of corrosion. The threads holding the cam into the pump body literally corroded and rotted away at which point the cam began spinning around the inside of the water pump with the impeller.
Forget a rebuild the pump body is now destroyed and the owner now needed a complete new RWP.. When "rebuilding" something this means "rebuilt" as in every piece that could wear or fail must be fully inspected and or replaced. This cam was totally dezincified and very weak hence the failure of the threads. This owner also has Drive Saver which isolates his engine from the prop shaft zincs meaning his only anodic protection was the teeny tiny HX zinc which was no longer even there... There is good reason the ABYC requires the shaft NOT be isolated from the engine and this is but one of them.
I know the pic does not do the dezincification justice but the coppery color around the screw hole and towards the edges is frail metal due to the zinc being eaten out of it. Any tech, who actually understands marine corrosion, even a little bit, should have spotted this galvanic damage in seconds and replaced that cam as part of the "rebuild"......
