Impeller reminder for 3.9 4 5 7.5 ...Mercs

Crosbyman

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I have been battling against my new impeller for a 1975 7.5 hp Merc. Lining up the impeller sqeezing the fins lining up to the "greased" & loose impeller key can be challenging with big fingers .

So simple a job after a few utubes....

The drive shaft is off-set from center in the small impeller housing.

The trick is to orient and align the impeller key using the widest gap side between the shaft and the housing itselft.

insert & bend the fins CCw in the narrow side of the housing and the extended fins will bend and slide nicely in the wider side over the key !

...voilà... easy as pie.. no cursing to :) Common knowledge for the old timers ..I know
 

saltchuckmatt

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Sorry guys, this is for the Crosbyman....can't send a pic in the im side of this platform.
 

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Scott Danforth

Grumpy Vintage Moderator still playing with boats
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Don't forget there are two different kits. You must know your shaft diameter
 

racerone

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And these impellers need to be replaced more often than other motors.----Especially if run in near freezing water.
 

Crosbyman

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yep I got the fat shaft sized impeller fits perfect. Freezing water ? ... that is for duck hunters... .I do not do duck anymore :) those impellers are tiny to say the least !
 

tpenfield

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I hate replacing the impeller on these motors (mine is a 1969 7.5) . . . and they seem to be short-lived. I'm getting about 3 years on an impeller.
 

Crosbyman

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it was a good learning. I do not recall having so much finger trouble on other small mercs. Garage is filling... 3.9, 4.0 on the boat, got what looks like a sailboat 4.0 and now this 7.5 which size permitting.... may replace my faithfull 4hp kicker
 

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racerone

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I twist the impeller as it is pushed down.----Making sure that keyway then lines up.-----Never an issue.----Have done more that 1 of these.
 

racerone

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Dec 28, 2013
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These little Mercury motors are actually very nice runners.-----Need a little more patience to work on them.
 

Crosbyman

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Latest 7.5hp revived new skeg, pump, carb job, nicks touched up, comp 120s waiting for ice out ( can't trun image ?)

1708375371806.jpeg
 
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