Hello to all, and Waterpump/Impellerquestions.

[rookiedave]

Hello all,

I am green as grass where boats and motors are concerned. I bought a old boat that I have been repairing and an old 7.5 hp dealer said about mid 60s era. serial begins 345. anyways, I know next to nothing, except what I have been reading on this site. You guys and gals have already been a huge help to me and my learning of my new hobby. Anyways my problem is this. I bought the old 75 (used of course) the guy said that there is nothing really wrong with the motor it only needed an impeller. Sooooooooo I bought the old motor and after all of your help, I was able to drop the lower end and get at the Water Pump. Well, there was only half or the waterpump in the lower end! So I found a Merc dealer and orderd the parts and finally after 3 weeks my parts came in I attempted to put the water pump back together. I followed the diagrams that the dealer provided and of course the practical advice from you guys. I found a thread about installation of the impeller which I followed....and after fighting the silly key for about an hour I finally got the impeller in the little cup in the lower half of the pump. then when I attempted to place the skid plate and top half on the impeller it would not sit flush with the bottom half. I was able to only close the water pump by using the 2 bolts and nuts to kind of squish the impeller into the housing. it closed and sealed but...... Is this the way it should be? I placed "according to the diagram" a little rubber gasket kind of thing around the shaft directly under the new impeller. should this spacer have been placed inside the little water pump cup? Now when I pull the starting cable it seems to me to be a lot harder to pull than before I installed the pump. I really do not even know how to get the thing started so if anybody could explain it to me a little more in detail I would love it also.
I have never been more frustrated in my life but at the same time I have been having a hell of a time knocking my little boat and motor back into shape. This site really is addictive..I run from my computer to my garage and try what I read here. then run back for the next difficulty.
Thanks again to you all, you really have been a great help already to me.
dave

 

[14pointer]

Re: Hello to all, and Waterpump/Impellerquestions.

Try going to youtube.com and you can watch some guys installing impellers sure helped me out seeing it instead of reading it...good luck...

 

[rookiedave]

Re: Hello to all, and Waterpump/Impellerquestions.

Thanks 14pointer, I will do that.

 

[Wingedwheel]

Re: Hello to all, and Waterpump/Impellerquestions.

If the gasket your talking about is kinda thick it could be the one that goes on the shaft after you install the cover. Thats a "silt slinger" and basically keeps crud off your drive shaft. There is a seal under the impellor, but it should have a nice flush fit to allow your impellor to seat in the cup.

 

[rookiedave]

Re: Hello to all, and Waterpump/Impellerquestions.

yes it was a little thick. the diagram i had said to put that one in the cup. the dealer did not give me any other gaskets that would fit around the shaft. only a few little brass ones for the cover and a little nylon brown gasket. there also was a thin little gasket that i thought went at the top of the shaft near the motor like a oil seal. there also was a plastic and metal combination gasket that placed at the top of the cover.

i fired up motor and had water come out steady tell tail (before I read this post) water not hot, but lower area shaft became warm very fast so i shut down. should i drop lower again?

 

[turtles11756]

Re: Hello to all, and Waterpump/Impellerquestions.

you need to see and compare with a parts list for your 1973' 7.5 hp merc. go to the parts catalogs at crowley marine.com look up your model and check you have ALL the parts.the impeller is installed with key way on shaft then the housing fits down on top. turn the driveshaft clockwise and apply hand pessure and the impeller will turn right into it's housing .grease everything lightly ,splines ,impeller , housing ,cup.check the gear lube in the lower and see what it looks like after changing it while your at it

 

[ss von scalliwag]

Re: Hello to all, and Waterpump/Impellerquestions.

Dave,
Just to let you knowI replied to your othe post regarding starting and cooling of the engine.
The rubber seal you discribed goes on the driveshaft ABOVE the water pump as previously mentioned.

 

[rookiedave]

Re: Hello to all, and Waterpump/Impellerquestions.

Thank you all, I went to the dealer today and ordered the correct parts. the tec there told me that the parts person gave me the wrong gasket and the told me the correct one should be in later in the week. I also ordered a new impeller since i am sure i cooked the other one. Since this is my first time I would not know the diffrence anyhow.
I would really like to thank all of you for your advice, I would not have tried this without all the help you guys have given me.