MattinTally
Seaman
- Joined
- Dec 6, 2009
- Messages
- 58
Over the past few years, purchased all the parts needed to convert a '63 18hp shortshaft to longshaft. Only part I couldn't find was the 5" longer water tube.... So, went to Lowes, purchased copper tube and coupler to match the diamter of the shortshaft water tube. Cut a 5" length, cleaned and sanded, fluxed, and silver soldered the two together using a standard copper coupler. Tested for air leaks and the solder job was tight.
Reassembled my freshly-rebuilt lower unit (all new seals, rings, bushings, impeller, oil, etc.). It took about 45 minutes of finese to get the driveshaft, shift shafter and water tube realigned. The first attempt yielded the "new" water tube was too long. Removed the L.U. and cut the modified water tube 3/8" shorter. Another 30 minutes I had it back together. Ran in barrell and no water was pumping after about 10 seconds. Shut down and removed lower unit again, found the water tube grommet on the lower end was pinched. Straighted it out and after another 40 minutes, had it back together a 3rd time. Still, no water. I'm absolutely positive the water tube is seated correctely on both ends.
I dropped the lower unit AGAIN, removed the water pump, housing, & plate and re-inspected the brand new (Sierra brand) impeller. Everything looked good. The driveshaft key was there. So, I then checked the water passages on the block.... Rigged up a water hose to another piece of spare copper... inserted it into the upper water grommet. Water passed immediatey thru the system and exited thru the exhaust port. Just to make sure, I removed T-stat plate & gasket and confirmed water was passing freely there (it was a new T-Stat & gasket anyhow, but I wanted to make sure). With my "test hose" rig, I was able to fire the motor up and it ran fine connected directly to a water hose (with the lower unit still removed). Block was very cool, could leave your hand on it forever.
Everything looks fine to me. I'm puzzled. This is my 3rd lower unit rebuild on the '58-'72 Fastwin era. I've never had trouble like this. Water in the barrel was the same height as I always run these motors in the past.
Is there any way to (while the lower unit is removed) test the water pump to make sure its functioning? I'm wondering if the driveshaft key isn't seating at idle? The last "funky" problem like this was the brass center ring of the impeller spun loose from the vanes - kinda like a spun prop. Had never seen that before (another Sierra brand part).
Any help would be appreciated.
-Matt in FLA
Reassembled my freshly-rebuilt lower unit (all new seals, rings, bushings, impeller, oil, etc.). It took about 45 minutes of finese to get the driveshaft, shift shafter and water tube realigned. The first attempt yielded the "new" water tube was too long. Removed the L.U. and cut the modified water tube 3/8" shorter. Another 30 minutes I had it back together. Ran in barrell and no water was pumping after about 10 seconds. Shut down and removed lower unit again, found the water tube grommet on the lower end was pinched. Straighted it out and after another 40 minutes, had it back together a 3rd time. Still, no water. I'm absolutely positive the water tube is seated correctely on both ends.
I dropped the lower unit AGAIN, removed the water pump, housing, & plate and re-inspected the brand new (Sierra brand) impeller. Everything looked good. The driveshaft key was there. So, I then checked the water passages on the block.... Rigged up a water hose to another piece of spare copper... inserted it into the upper water grommet. Water passed immediatey thru the system and exited thru the exhaust port. Just to make sure, I removed T-stat plate & gasket and confirmed water was passing freely there (it was a new T-Stat & gasket anyhow, but I wanted to make sure). With my "test hose" rig, I was able to fire the motor up and it ran fine connected directly to a water hose (with the lower unit still removed). Block was very cool, could leave your hand on it forever.
Everything looks fine to me. I'm puzzled. This is my 3rd lower unit rebuild on the '58-'72 Fastwin era. I've never had trouble like this. Water in the barrel was the same height as I always run these motors in the past.
Is there any way to (while the lower unit is removed) test the water pump to make sure its functioning? I'm wondering if the driveshaft key isn't seating at idle? The last "funky" problem like this was the brass center ring of the impeller spun loose from the vanes - kinda like a spun prop. Had never seen that before (another Sierra brand part).
Any help would be appreciated.
-Matt in FLA