water pump impeller key

[flattop1]

I have a sierra wp kit #18-3393 that is supposed to be right . problem is it has a woodruff key and my 1977 140 has a wedge shaped plastic key.
is there a way to use this or is it wrong. if wrong do you know the proper kit number?
the manual i have shows 1 key 1 roll pin and 1 key looking thing that fits in the flat, in 3 differnt photos or diagrams.
Thanks
Tony

 

[Benny1963]

Re: water pump impeller key

i use the plastic key that came with my sierra kit .
that sierra kit has and oring that gos between cup and housing
isted of the seal that evin uses on houseing at drive shaft

 

[flattop1]

Re: water pump impeller key

benny which kit did you have?
the kit i got has a woodruff key (halfmoon).
The output shaft /lower unit has the plastic wedge.
I have made a square key that fits the recess and impeller would this work?
Tony

 

[5150abf]

Re: water pump impeller key

Can you reuse the part that was on it, use the new impeller and the old wedge?

 

[flattop1]

Re: water pump impeller key

i don't think so as the new impeller has a key way.
the boat shop said they sometimes did, i just do not see a way to make the wedge work. by all indications this is not the right kit for this lower unit,or a mid year change or omc used up old stock on this production run.
Thanks Tony

 

[Benny1963]

Re: water pump impeller key

flat top you will need proper key makeing one is risky at best the waterpump
believe me you dont want to fail ,it will cost you dearly when ya here the buzzer ya usually have done some damage ,
check brps diagrams my motor is a 1983 150 it uses the plastic half moon .

 

[Vic.S]

Re: water pump impeller key

by all indications this is not the right kit for this lower unit,or a mid year change or omc used up old stock

the same part is listed for '78, '77 and 135hp'76 models and it appears to be a Woodruff key

You do need to source an impeller with the correct type of key for your shaft. They will all have to match each other. I have also come across a round metal key (cylindrical) rather than the flat triangular plastic key. Although either could be fitted to the shaft the keys and impellers were not interchangeable with each other.

Maybe your engine is a bitsa or have you had it from new.

 

[flattop1]

Re: water pump impeller key

vic
I have not had it since new, just obtained it, looks to be all original or it had to have been changed at a very early time in its life.
the manual has a key similar to what you described a straight key on a cylindrical base, if i had one off these all would be well.
from what i can see in the online catologs an impelller off a 1979 has the wedge style key. getting this impeller seems to be the solution.
Thanks
Tony

 

[Vic.S]

Re: water pump impeller key

The diagram I am looking at for a '79 model appears to have a round (metal?) pin that sits vertically in the impeller. That's what my original was like. The first replacement (non OMC) had a triangular plastic key. Either type fitted against the flat on the shaft but the impellers were slightly different so each had to be fitted with its correct key.

It will be worth comparing the impeller for a '79 model with your old one to see if they are the same externally and bore diameter (the keyway will be a bit different for the round metal key or the wedge plastic key)


You'd never tell if your engine had been fitted with a later gear box assembly if the paint colour was the same and it fitted correctly and even less likely to be able to tell if the drive shaft had been swapped.

 

[flattop1]

Re: water pump impeller key

vic i agree totaly .
just don't have any thing to compare. will have to take it all to dealer for visual id.
Thanks
Tony