water pump

[kwoolard]

I am replacing the water pump in my 1974 40 hp, 2 stroke Johnson. The water pump kit that I took out apparently was an updated model since the water pump kit I purchased to replace was manufactured completly of steel. I was told the purchased kit was the factory kit. However, I am a little concerned because this new water pump kit did not come with any seals for the pump plate or the drive shaft even though the kit I am replacing did. Is this a problem or did this motor not have any seals in the original factory water pump kit.

 

[Dhadley]

Re: water pump

Tell us what you mean by "manufactured completly of steel". What brand of pump is it? Whats the part number on the box?<br /><br />Good luck!

 

[kwoolard]

Re: water pump

The water pump cover or housing is all metal, unlike the one that I am replacing which is plastic and has a metal housing insert for which the pump rides in. However, my concern is should there be gaskets and shaft seals for the factory pump kit? <br /><br />Outboard<br />Model # 40EL74S if it helps.

 

[S.T. Marine]

Re: water pump

Depending on the new style it might not. I would assume it should have a seal for the driveshaft. That is always common. As to the casing its just an updated case probably made from stainless. It might not need a gasket... does it have a o ring seal or just flat...? Wouldnt hurt to throw some perfect seal around it if thers not gasket good Luck!!

 

[ob]

Re: water pump

kwoolard,Bombardier/ OMC redesigned some of their waterpump assy and some don't use the seal"Oring" between the impeller and housing cup.My 95 70 hp is one example.On mine the impeller also changed from a six to a three flute.Never seen one with a metal pump housing. <br /><br />pump kit Here's a shot of the pump kit from one supplier for your motor.

 

[kwoolard]

Re: water pump

what about the flat seals between the gear casing and the impeller plate. i don't have any seals for that either. it just seems strange that a pump would not have any seals, especially a shaft seal???????

 

[Dhadley]

Re: water pump

Again - What brand of replacement pump is it? Whats the part number on the box?<br /><br />Lets start with the basics.

 

[kwoolard]

Re: water pump

The water pump is OMC brand 391741. This is the kit with housing. The dealer claims it is the original pump kit that was on this 1974 40 hp johnson. The kit came with an impeller, impeller plate, housing, and impeller key. No impeller plate seals. And I don't see a place for a drive shaft seal. If it doesn't need a shaft seal please explain how the exhaust pressure will not interfere with the pump. <br /><br />Thank you guys for all of your help, it is really appreciated.

 

[ob]

Re: water pump

Kwoolard,Without being able to see the impeller and housing assy I can only assume that the impeller itself provides for seal between housing and driveshaft.I don't think engine exhaust would play a part in pump operation as the cavity where pump is located keeps pump housing submerged while running.If you feel that the kit you purchased falls short of a seal kit then I would ask dealer to pull up a fiche drawing and review the installation with one of his mechanics.

 

[clanton]

Re: water pump

Numbers check ok. If pump housing does not fit, may be different gear case. If the kit is a orignal OMC kit with instructions that has a kit parts list with kit, and you have correct gearcase it should work. The houseing is probley aluminum, and the only seal is the rubber inpeller that is molded around the impeller hub. this part of the impeller seals against the wear plate and housing. You can see the wear marks on the old housing and wear plate. Some of the later model engines had different drive shaft, and some of the kits came with 2 different impellers for the different drive shafts, and the only way to know which drive in the engine, was to remove gearcase and look at drive shaft.

 

[Dhadley]

Re: water pump

OK - now we know where we are. That is the correct standard kit for a 1974 40 hp model number 40(R,RL,E,EL)74. The impeller plate does not require seals. There are 2 seals under the plate (which may be superceeded to a double lip seal) in the lower unit housing itself. There is no seal required in the top of the pump housing. <br /><br />What you removed is what is refered to as a "chrome kit". A plastic housing with replaceable liners. The liner kit is 390342 and the impeller kit is 390286. Either will work.<br /><br />Good luck!

 

[kwoolard]

Re: water pump

Let me recap. For this model there is no shaft seal(the impeller serves as the seal for the shaft and the impeller plate) and there are two seals under the impeller plate(the gearcase side). <br /><br />These seals are shaped similar to the impeller plate and seal between the impeller plate and the gearcase?<br /><br />Where can I get these two seals?

 

[ob]

Re: water pump

Kwoolard ,The only seal under the plate that is of concern is the driveshaft seal.This prevents water intrusion into lower unit.It is likely a round "lip seal."As long as you have it apart I would recommend installing a new one. Dealer should have it .