4hp Evinrude impellor help needed

neilmw

Petty Officer 1st Class
Joined
Jul 19, 2004
Messages
245
I have a 2cyl 4hp rude which i think is about 1985 model, my problem is that i removed the lower leg to change the water pump but the shaft remained in the top of the engine and the leg came of the bottom? i thought the shaft was meant to stay in the bottom as I cannot see how to get the lower unit back on because of the key way for the impellor, if the shaft is meant to come off with the lower leg how do i remove it from the top, or is it meant to stay in the top and if so how do get the lower unit back on?
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: 4hp Evinrude impellor help needed

The top of the drive shaft is splined, and under normal circumstances, it should just pull out of the crankshaft. If it sticks, it's probably because of 2 reasons. Either it's rusted at the shaft/crank junction or there's been metal displacement in the spline area of the junction. You can try inverting the motor and dribble PB Blaster or other 'bust rust' penetrating oil down the shaft. This should be allow to soak. Using a pair of pliers, try rotating the shaft counter-clockwise, then clock-wise to free the shaft. Be sure your pliers are not used on the section of the shaft where the pump or pump housing are located. You don't want to 'knarf'(technical term) the bearing surfaces.<br /><br />Replace the drive shaft back into the lower unit, you may have to slightly rotate the prop to re-engage the lower drive shaft splines back into the lower unit pinion gear.<br /><br />Be sure you grease the upper drive shaft splines before you re-install the lower unit. The grease helps to prevent rusting again and helps the torque loading on the shaft splines.
 

neilmw

Petty Officer 1st Class
Joined
Jul 19, 2004
Messages
245
Re: 4hp Evinrude impellor help needed

yep! you were bang on! left it soaking in some wd overnight then gave it some gentle persuation.<br />all sorted now, thanks for the help
 

Xcusme

Commander
Joined
Apr 21, 2003
Messages
2,888
Re: 4hp Evinrude impellor help needed

Hey!! That's great news. Be sure you grease the splines on the driveshaft only (no grease on the very end of the shaft) when you reassemble things. You certainly don't want to run afoul with a stuck driveshaft the next time you replace the water pump/impeller. Well Done. ;)
 
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