1974 Evinrude 40 HP impeller change

[buddhapi]

I'm needing to replace the water pump impeller on a 1974 Evinrude 40455S. OMG!! do I need to pull the drive shaft out and install the impeller and housing from the bottom?? thank's; Greg

 

[JDusza]

Re: 1974 Evinrude 40 HP impeller change

Are there screws in the top cover of the water pump?
You may be able to access the impeller from the top. How's the drive shaft look, rusty?
If the drive shaft comes up from the gearbox, it should slide back down, picking up the pinion.
How's the lower unit oil look?

 

[buddhapi]

Re: 1974 Evinrude 40 HP impeller change

there are 3 bolts about an inch and a quarter long that hold the water pump housing down to the lower unit. the top of the drive shaft is about .060 bigger than where the impeller slides on. the only way I see is to pull the shaft. there are Allen head bolts holding the 2 lower unit cases together. I'm going to change the lower unit lube when I get this motor up and running. there doesn't seem to be excessive play in the lower unit. I got this boat and motor from a good friend, and he swears it has no issues. this motor was bought new, and transferred to a 1986 boat later in life, that they also purchased new. I got it all for free because the stealership told him they no longer made water pump impellers for this type of lower unit. I bought all the pieces I needed! the drive shaft is rust free

 

[boobie]

Re: 1974 Evinrude 40 HP impeller change

Something is wrong. I've never heard of having to remove the d/s from the lower unit to replace a water pump impeller. Better recheck things.

 

[buddhapi]

Re: 1974 Evinrude 40 HP impeller change

Okay. this is what I incurred today!! it looked to me like the upper shaft is pressed over the lower shaft, so I grabbed a brass drift and started to tap the shaft upward by the split. the whole shaft came out of the lower unit. this is definitely not Mercury @$$anine design! I put the impeller in the cup, and inside the upper housing and slid the assembly onto the shaft. I then installed the key and slid the assembly down, and commenced to lower the shaft back into the lower unit. I soon realized that the shaft doesn't drop in the last 3/8", where I can see the lower seal used to ride on the shaft. does anybody know what I did wrong? where to go from here? I can shift R N F, and the prop shaft moves the drive shaft, but it doesn't seem like it goes all the way down into the lower unit. the impeller housing definitely isn't down far enough either.

 

[boobie]

Re: 1974 Evinrude 40 HP impeller change

Have you got a model # of this mtr ?? I'm confused.

 

[buddhapi]

Re: 1974 Evinrude 40 HP impeller change

40455S it comes out as a 1974 40hp Evinrude, but I don't know if the lower unit is original to the motor, although, it has been running for years as a complete unit.

 

[buddhapi]

Re: 1974 Evinrude 40 HP impeller change

well, I tried again today, and I cannot get the drive shaft back into the pinion gear. I even lightly tried to tap it down with a rubber mallet. it does not look like my splines are burred up at all on the bottom. even the pinion spline look's nice and clean...what I can see with a flash light.