1976 Evinrude Model 40R, Manual start tiller controlled outboard runs great. Started first day of boating season and no cooling water coming out with the exhaust in the back. Shut engine down before over heat and pulled lower unit to replace impeller, body, plate, gaskets etc. Cools great now. BUT... When throttle is advanced just to the point of resistance on the tiller twist handle the engine runs great and appropriate power is delivered to the prop. When throttle is advanced further (i.e. the spark timing is being advanced) then it seems like the powerhead and lower unit disconnect and the engine revs and the boat slows down. I searched the archives and found a fix that required adjustment of the coupler for the shift shaft. I adjusted so that maximum forward throw was achieved while still allowing a solid reverse(don't have to hold shifter in reverse)and it works much better but still slips. Any suggestions? I did check the shear pin also. This prop is a solid prop no thru-hub exhaust so there is no hub to slib. It is shear pin through hub through shaft through hub and then held on by a slip on cap with cotter pin to hold. This is my crabbing motor and the season is upon us here on the Oregon coast. I need my 16' Valco and outboard!!!! Thanks in advance for any help. One last thing I just thought of. When I replaced the water pump the drive shaft extended WAY out of the lower unit where it normally runs. I had to push it down more than a couple inches to get the keyway for the pump impeller to line up. Does this help? LF<br /><br />Loren
<br />The brass pin has a lower shear strength, so it will shear prematurely. Also, if your operating in salt water, your brass pin may dezincify (if it's yellow brass instead of admiralty, that is). This would cause it's strength to be lost over time...<br />Anyway, carry some cut-up nails and tools until you get some SS ones.