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Impellor replacement

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alexdyer

Contributing Member
i am replacing my impellor on

i am replacing my impellor on a johnson 1980 70hp 3 cylinder and have a question!
the new impellor has come with 2 wedge shaped keys to fit it with!
My original has a single slot that a half moon shaped key fits into to hold it in place.
do i need to put the orginal key in aswell as the wedge shaped bits? if i only put the half moon key it takes the slack up and holds in position however i am unsure as to weather it will stand up to the forces of the motor turning it! if i turn the shaft in a counter clockwise direction i can feel that the shaft moves free of its holding position.
any help will be greatly appreciated
 
The package comes with instruc

The package comes with instructions. However it has to do with the same part being used in OLD / NEWER engines.They no longer use a metal key. It may well be that you have an older driveshaft in your motor and you may need to see a dealer and get the correct impeller.Your shaft should have a flat area for the plastic drivers to work.
 
"Hi thanks for your reply.
Th

"Hi thanks for your reply.
The new one did not come with any instructions which i thought was strange, i thought i must just be missing the point!
so thought i would ask for some advise.
the shaft does seem to be round though and the part was direct from an omc dealer"
 
You either have the wrong impe

You either have the wrong impeller or the wrong shaft in the motor.Take the parts to a good dealer to get a quick answer / solution.
 
unfortunatly my closest dealer

unfortunatly my closest dealer is more than 100 miles away! I have to do everything by post.
thanks for your help though i'll give them a call.
 
Take a grinder and carefully m

Take a grinder and carefully make a flat surface that the new 'plastic' wedge will fit on to. The old impeller with a key-way slot might be difficult to find.
 
Hi Morten thanks for the advis

Hi Morten thanks for the advise!
Would you grind a flat opposite the key slot or to the side?
 
"I usually grinded ON the slot

"I usually grinded ON the slot to avoid weakening the shaft more than needed. Watch out for heat and sharp edges. If the shaft is still in the gearhousing, cover the seals so no 'dust' gets there."
 
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