Help on a 77 75hp Johnson water pump please

[Desertboater]

Hi to all,

First time at checking the basics you kind folks adviced me to do upon buying my first boat.

I decided today to take the gearcase off and check to see if my impeller was in good shape if not so i can replace it. Upon opening it the impeller was in very good shape but my impeller housing plate had grooves on one side of it so I'll need to replace that.

The part I'm confused with is the housing gasket of the water pump. When I removed it the housing has a "ring" type gasket that goes around it which was in pretty bad shape and didn't really seem to fit properly. I look it up on my service manual so I can order it and it calls for a "flat" gasket not a ring gasket. I hope I'm making sense to you guys. I also checked the evinrude/johnson website to verify the manual and it also calls for the same flat gasket not the ring type. I did notice that the gasket that the manual calls for has the same shape as the housing although the housing has a groove for the ring gasket. Damn I'm confusing myself!! Is it the wrong housing for this motor 75elr77? Or can someone help me as to which one should I buy, gasket that the manual calls for or the ring type that it came with?

Sorry for the rambling guys I apologize for that.

 

[Daviet]

Re: Help on a 77 75hp Johnson water pump please

It looks like the 79 pump uses an o-ring. Maybe someone replaced the pump before and used a 79 pump kit. You can go to johnsons web site and compare the two different pump parts.

 

[Les Robb]

Re: Help on a 77 75hp Johnson water pump please

If the blades of the impeller have taken a curved set, I would replace it anyway, not forgetting the o-ring at the top of the shaft and the water tube gasket. Two things will kill a 2 cycle engine quickly, no oil in gas and no cooling water.

Just my opinion ya'll but $45.00 is cheap insurance for a good motor.

 

[Desertboater]

Re: Help on a 77 75hp Johnson water pump please

I checked the 79 model at the Johnsons website and it does seem to be the water pump housing that I have. It does call for the o-ring.

My next question is, should I leave that alone and purchase the o-ring and impeller housing plate and reinstall. Would that be fine? Or should I purchase the entire water pump assembly for what it actually calls for. I my opinion and I might be wrong, they both look the same but one calls for the o-ring which is the 79 model and the one on my sevice manual calls for the flat gasket which is for the 77 model.

Impeller is fine so I don't need to purchase that.

One other thing I noticed is that Iboats doesn't have the whole kit available for the 77 model and the Johnson website says dealer item only. Maybe the previous owner had a hard time finding one for the 77 model.

Thanks for the help guys

 

[Desertboater]

Re: Help on a 77 75hp Johnson water pump please

I checked the 79 model at the Johnsons website and it does seem to be the water pump housing that I have. It does call for the o-ring.

My next question is, should I leave that alone and purchase the o-ring and impeller housing plate and reinstall. Would that be fine? Or should I purchase the entire water pump assembly for what it actually calls for. I my opinion and I might be wrong, they both look the same but one calls for the o-ring which is the 79 model and the one on my sevice manual calls for the flat gasket which is for the 77 model.

Impeller is fine so I don't need to purchase that.

One other thing I noticed is that Iboats doesn't have the whole kit available for the 77 model and the Johnson website says dealer item only. Maybe the previous owner had a hard time finding one for the 77 model.

Thanks for the help guys

Any taker on this one????? HELP ME OUT ON THIS ONE GUYS

 

[Daviet]

Re: Help on a 77 75hp Johnson water pump please

I would think that if the 79 pump has been working properly, I would go ahead and replace it with the same kind. It's kind of like six of one and onehalf dozen of the other. What ever is easiest to get, use it.

 

[James R]

Re: Help on a 77 75hp Johnson water pump please

Looks like a back yard mechanic has been in here. On the other hand someone could have change the lower unit completely for another year model.
If you go with a flat gasket then you will need to change the pump housing.
Look at the drawings to determine which parts to go with.

 

[Desertboater]

Re: Help on a 77 75hp Johnson water pump please

Thanks guys for the replys,

James I think you hit the nail in the head. I think the prev owner had a hard time finding the 77 model and went with the 79.

Daviet your right about the water pump working before so I think I'm gonna go with ordering the o-ring and the new plate and slap it back on.

Anything else I should take a peek at while I have the gear case off?

Thanks a bunch I really appreciate you guys taking the time.

 

[jtexas]

Re: Help on a 77 75hp Johnson water pump please

You can identify the '79 housing by the indentation on the mating surface, which the seal fits into.

ishopmarine usually has little pieces parts like gaskets, but the shipping cost for a $2 part will eat you up. It's just a plain flat waterproofed fiber gasket.

if your impeller blades are bent at all, then I highly recommend replacing it.

 

[Desertboater]

Re: Help on a 77 75hp Johnson water pump please

Parts have been ordered!!

Thanks a bunch guys

Hey jtexas I liked the ishopmarine website..... You were right about the shipping though. Through them my shipping cost was $20.00 through evinrude/johnson website same parts $7.95.


Thanks again guys....

 

[mikesea]

Re: Help on a 77 75hp Johnson water pump please

i do hope your putting in a new impeller,not doing so would be like rebuilding a car and putting old tires on it,a tire blows and you can wreck,impellers are general maint items that need changing ,in south fl.its suggested yearly bregardless how great your running,i say change plate,impeller and oring,gasket under plate too,might be suprised to find a whole pump kit costs about the same as those parts

 

[Desertboater]

Re: Help on a 77 75hp Johnson water pump please

I agree 100 percent Mikesea, I did check it and it looks in very good condition. No cutting corners!!!

In fact my brother was getting on me for ordering all these new parts for my boat. I just did the carb rebuilt last week, this week I dropped the gearcase to check my impeller so I'm getting there. Once I get my parts in I'll reassemble and change gear oil while I'm at it. I am learning alot and enjoying it along the way.

Learning from you guys Thanks...