1979 Johnson 4hp Water Pump

[Ranger Dave]

When do I know when its time to replace the impeller for the water pump?

 

[alcan]

Re: 1979 Johnson 4hp Water Pump

Hi Dave<br />The water pump empeller on an outboard is a annual service item. Most will run longer. The trouble is varing conditions. I don't think anybody knows for sure how long. Sometimes the rubber vanes will degrade and block up the cooling system. Quite often the hub of thhe empeller will delaminate from the rubber. In this case the empeller will look fine. The trouble is the hub spins inside the rubber and doesn't pump. As these parts are relatively inexpence compared to the possible damage that can occur, they are hardly worth taking a chance on. The L/U should be removed and the driveshaft splines,propshaft lubed and gear oil changed at least annually any way.

 

[Ranger Dave]

Re: 1979 Johnson 4hp Water Pump

Thanks.<br /><br />Is there away to clean out the water tube that runs up to the block?<br /><br />My gear case top seal started leaking and I replaced the seal but gear oil got everywhere. I'm think some of the oil may have been pumped up to the block and maybe not allowing a good flow of water.

 

[alcan]

Re: 1979 Johnson 4hp Water Pump

Hi Dave<br /> Sure, you can blow compressed air up the pipe or run some water up there with a garden hose and a home made adapter. How ever I don,t think gear oil or any other type of oil would cause a problem. I would think it would do more good than anything. Be sure that you check the water tube gromets and that all else with the pump seals nicely. Did you in fact install a new pump kit?

 

[Ranger Dave]

Re: 1979 Johnson 4hp Water Pump

No. I replaced just the driveshaft seal and the propshaft seal. The driveshaft seal leaked after replacing it so I replaced it again. When I took the pump a part to get to the seal the water pump was full of gear oil.<br /><br />I'm going to call and see if they have an impeller for this trusty motor. I use it on a 14' canoe.

 

[alcan]

Re: 1979 Johnson 4hp Water Pump

Hi Dave<br />In your case you may need the pump kit. this would include a plate,gromets,screws, etc. Of course the empeller.