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1975 40 HP Evinrude, Model 40555C

T

tomfg

New member
When installing a new water pump impeller, I notice the driveshaft splines on the top side are quite
worn. Does the drive shaft splines slide directly into the engine crankshaft, or is there a replaceable
part with the female splines between the crankshaft and driveshaft?
I looked on the BRP catalog diagrams, but can't tell.
If worse comes to worse, I may be able to find a different drive shaft, but if there's mating splines
in the crankshaft that are shot, I'll be rowing :-(
Thanks for any clues!
 
The splines are part of the crankshaft. -------No replaceable coupler there.-----------If the motor has hit something and the exhaust housing is bent , that may account for the wear on splines.--------------On the other hand people refuse to do proper maintenance on motors, those driveshaft / crankshaft splines need some grease on a regular basis.
 
Normally those splines last just about forever. However, for some reason someone will neglect to install the needed "O" Ring in the groove just below the top driveshaft splines and/or (as reacerone mentions) apply grease to the splines which leads to wear. Another disasterous result of not applying grease and that "O" Ring is that water will enter that area and cause the driveshaft splines to rust tightly to the crankshaft splines, practically a weld like condition.

Also Private Message Sent...........
 
Thanks for your replies. The motor is back together already, and tried it out on the lake yesterday. Glad to say, the new waterpump
impeller is working great, and it's running and shifting okay. When I had the lower unit off, I do not remember seeing a o-ring groove on the top of the driveshaft. There was no rust on the driveshaft. Just looked in the manual, and it shows the o-ring in the end of the crankshaft. Anyway, I did re-grease the splines, and will keep my fingers crossed. Thanks, Tom
 
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