Correct rotation for impeller

[Khenders]

I installed a new impeller in an 85 15hp johnson last night. This morning I woke up and something didn't seem right. The shop said to slide the pump down and turn it clockwise. But this twists the fins CW and I seem to recall reading somewhere here that the shaft turns CW. This would mean the fins should be pointing CCW. Right?

 

[Pony]

Re: Correct rotation for impeller

I am pretty sure that either way you put them in, the fins will flip and correct themselves on their own.

 

[OptsyEagle]

Re: Correct rotation for impeller

You want to turn the drive shaft clockwise, not the pump housing clockwise. If you put a slight downward pressure on the pump housing while turning the driveshaft clockwise, the fins of the impellor will end up pointing counter-clockwise (when looking down at it through the pump housing, not that you will be able the impeller this way).

This will be the correct orientation of the impellor. If done wrong it will most likely correct itself ... or the impellor will rip apart in a multitude of pieces your engine will overheat, your powerhead will warp your gasket will blow and your engine will be worth its weight in scrap metal.

It could go either way. Good luck.

 

[mkrupp]

Re: Correct rotation for impeller

i was always told it doen't really matter what way the fins face, if you have soap or some other lube on it they will correct themselves right away with no damage to be done(hopefully). I put mine and didn't check the direction they were facecing so either i got lucky and put them in the right direction or it doesn't matter

 

[Walker]

Re: Correct rotation for impeller

The impellor rotates in and offset housing. On one side the fins get almost 100% straight and on the other side they get bend considerably. The bending action makes the space between the fins smaller forcing the water out into the cooling system of the motor. With a new impellor it will correct itself of put in with the fins bent the wrong way.

 

[Pony]

Re: Correct rotation for impeller

... or the impellor will rip apart in a multitude of pieces your engine will overheat, your powerhead will warp your gasket will blow and your engine will be worth its weight in scrap metal.

It could go either way. Good luck.

I sincerely doubt that would be the case with a new impeller. I think the Service manual may actually even have you install it in reverse and have the driveshaft correct the fins.

 

[perkdp]

Re: Correct rotation for impeller

when put in wrong, bend in the direction of rotation, the tip of a fin can catch on a dry housing enough to flip it back against the tip of the next fin.
This causes a dead space in the water flow. so, if you have a 4 fin impleller, 1 of these could cut the flow by 1/4. two would cut it by 1/2.

as long as all the fins turn back the right way your good.
as long as all the fins stay wrong your good.

 

[Khenders]

Re: Correct rotation for impeller

Thanks to all for your inout. I will put the issue of whether they will correct themselves to rest this after noon (pacific time). Since I now know for a fact that they are bent the wrong direction, being lubed well with soap and not yet placed it in water, I will turn the the shaft CW for a few rotations and then remove the case once again to prove to myself what happens.

I suppose I can let everyone else in on the results with a follow up post.

 

[Gary H NC]

Re: Correct rotation for impeller

You guys are correct, Quoted from the Johnson service manual "Turn drive shaft clockwise while pushing down on the housing over impeller"....

 

[Khenders]

Re: Correct rotation for impeller

Well...survey says...it rotated into the correct position.
Now the nut on the shift linkage is stripped.
At least I have a new impeller.