OMC waterpump Question

[Metalwizard23]

Ok While im doing OTHER things on my lower I figured time to do the impeller and pump housing..

THe guy at our local parts place said this is the correct part. (see image the one with blue plastic plugs in it) even though its different. but then again he looked at me funny when he asked if it was electric shift or mechanical and said "I don't know what that means" so my confidence in him is pretty low.

anyways can I use this new housing with the plugs in it to replace the one without plugs?? it seems to me that it would not seal correctly because there is a relief by those holes..

 

[Bluedogfishing]

Not sure with an answer but is that hole in the new one offset?

 

[Metalwizard23]

all of its offset. they only go in one way.. any of the other three ways NOTHING lines up..

the offsets are the same on both..

 

[Redrig]

yup , that is right , the impeller housing on all stringers are the same, use the plugs and new impeller and grease all of the splines while you have everything apart .

 

[kenny nunez]

It took me a little while to remember the purpose of the plastic pugs.
When OMC was selling inboard marine engines the belt driven raw water pump used that same aluminum housing enclosed in a cast iron housing.
Electric shift units were made until 1977 and 1978 was the first year of the 400-800 series.

 

[Metalwizard23]

yup , that is right , the impeller housing on all stringers are the same, use the plugs and new impeller and grease all of the splines while you have everything apart .

Thanks again. just wanted to be sure..

Yep everything gets grease etc! just wanted to be sure that housing was ok to use! hate to create a leak inbetween the exhaust and the cooling water...

 

[Metalwizard23]

OK I feel REALLLLLLY stupid now

What direction does the impeeler go..

Its been a week since I took it apart and i cant for sure remember...

the book say turn to the right... does that mean turn the shaft to the righ from out side or the impeller to the right from the inside.

anyways Im attaching a picture tell me if im correct or wrong....

thanks... i feel pretty dumb now

 

[Metalwizard23]

Im pretty sure that picture the impeller is backwards.

I must really be having a brain fart

where the HECK does the BIG oring go.

if you put it around the impeller housing it does NOTHING it does not seal against anything.. but that is the only place it seems to fit..

ARRRRRGH im loosing my mind.. something so stinking siple and I messed it all up

 

[kenny nunez]

The large “O”ring goes around the outer of the pump housing to seal out exhaust gasses. Use #2 Permatex to seal both sides of this stainless plate. Do not worry which way the impeller is facing, when you start up the engine it will sort itself out.
Just be real sure that the 1/2 moon key is tight in the slot, I always “dimpled” the shaft to tighten the key slot.

 

[Metalwizard23]

ok with the oring on the outside of the impeller housing.. it does NOTHING nothing closes tight enough to seal against that oring... theres like a half inch gap between the two pieces...

 

[Metalwizard23]

OK so looking at the assembled pump INSTALLED in the housing.. you see the oring its touching the bottom of the swivel housing.. but there is a good 1/2" to 1" space between the swivel housing and the upper gearcase housing... how is that sealing ANYTHING???

 

[kenny nunez]

I know what you mean about the gap, but that is why it is used and I agree with you and often wondered the same thing.

 

[Metalwizard23]

Thanks Kenny so Thats how it goes in there... crazy that aint going to seal a dang thing LOL stack 20 of them maybe LOL

I guess years of wrenching makes you go... HUMMMMMMMM that dont work

as for the impeller.. I was able to look at the old plate and see a little "imprint" of the old impeller. Im sure I have it going the right way now.. (opposite of the picture I posted)

also once installed I turned the ball gear in the direction it travels.. and that seems to be the correct direction... im sure the vanes on the impeller Drag behind the hub... not push in front on them..

thanks everyone for the help... Ive got NO ONE out here that has a CLUE on OMC stuff its good to have people that are willing to help.. (good or bad LOL)

cant wait to get this girl in the water! I got one Test run.. and WOW is she fast.. until it stopped shifting (see my other thread... im converting to mechanincal shift the hydro went kaboom LOL )

 

[kenny nunez]

The water pump goes from a positive style at slow speed and a circulation style when on plane , the blades actually fold in from the pressure of the forward movement of the boat. That is why they last for years.
Good luck with the lower gearcase.

 

[Metalwizard23]

OK I have an OLD electric shift in my junk pile.. I went and looked at it... in the picture I posted showing the ORING.. on my mechanical... you can see where I put the oring..

On the old electric.... its not there.... I can see an oring.. so I think i still have this wrong

anyone have a picture where that big o-ring actually goes... none of the 3 manuals I have show it it just says to put it on the housing..

 

[Metalwizard23]

I found a picture in one manual that shows what I THINK is an oring.. it LOOKS as if it goes BETWEEN the impeller housing and the flat metal plate... if so I need to take this all back apart.

I really need to know where this o-ring goes.. HELP!

 

[Metalwizard23]

OK in this image... PART NUMBER 76..... where does that go??? between part number 32 and 29???? or does it go one the OUTSIDE of 29... because it fits AROUND 29 (impeller housing) but seems to seal nothing...

 

[Redrig]

It does go around the impeller housing ,I just checked my manual and its sealed with permatex like kenny said. Then when the swivel portion is put on it should be fairly tight in there when torqued to specs

are you sure that you have the impeller housing fully seated ?

 

[Metalwizard23]

im 100% sure its seated... theres still almost an inch before it touches the oring..

So you are saying it goes around the impller housing. to seal to the SWIVEL housing. thats what I have and like i said theres nothing to crush that o-ring.. LOOK AT THE PICTURE I POSTED BEFORE.. ill reattache it.. I can see it through the exhaust port.. LOOKING at my OLD electric shift I see NO o-ring in that location...

 

[Metalwizard23]

OK I just pulled apart the Electric shift that I have... NO BIG ORING like that anywhere..

Just weird...

im guessing that or-ing has to be for the OTHER side... where the pinion gear is

I guess im leaving it like it is and hoping for the best...

How can something so simple be so complicated..