1978 15hp johnson water tube help.

[SMOKEHOUSEROB]

hello ,i have a model # 15R78B , with the lower end off, i hooked a water hose to the water tube assembly , water comes out the pee hole and some where else up at the top by the exhuast tube at the power head, . Does that meen i need to replace something ? or is that normel, my thats what a shop told me. I thought the water only came out the pee hole. need to find out before i put the lower unit back on, thanks this is my first outboad,

 

[bktheking]

Re: 1978 15hp johnson water tube help.

hello ,i have a model # 15R78B , with the lower end off, i hooked a water hose to the water tube assembly , water comes out the pee hole and some where else up at the top by the exhuast tube at the power head, . Does that meen i need to replace something ? or is that normel, my thats what a shop told me. I thought the water only came out the pee hole. need to find out before i put the lower unit back on, thanks this is my first outboad,

There is a grommet that cracks and breaks over time, it is at the top of the water tube and is in the exhaust housing. The only way to replace it is to pull the powerhead and remove the exhaust tube and replace the base gasket and grommet that sits in the exhaust housing. I will PM you a video I made which shows you what it looks like.

 

[SMOKEHOUSEROB]

Re: 1978 15hp johnson water tube help.

There is a grommet that cracks and breaks over time, it is at the top of the water tube and is in the exhaust housing. The only way to replace it is to pull the powerhead and remove the exhaust tube and replace the base gasket and grommet that sits in the exhaust housing. I will PM you a video I made which shows you what it looks like.

So you are saying if i hook a hose to the bottom of the water tube the only place water should come out is the pee hole?

 

[bktheking]

Re: 1978 15hp johnson water tube help.

So you are saying if i hook a hose to the bottom of the water tube the only place water should come out is the pee hole?

I guess the only other option is that it does not have a thermostat installed or it is stuck open, if it were closed water wouldn't flow through the system. If the stat is in good working order then I would hazard a guess at the grommet I suggested.

Pic courtesy of The Machinest

 

[SMOKEHOUSEROB]

Re: 1978 15hp johnson water tube help.

I guess the only other option is that it does not have a thermostat installed or it is stuck open, if it were closed water wouldn't flow through the system. If the stat is in good working order then I would hazard a guess at the grommet I suggested.

Pic courtesy of The Machinest

that diagram shows that water comes out threw the exhaust tube also. i just dont want to pull the power head and the gromet is good and the extra water coming back down is normel. thanks

 

[bktheking]

Re: 1978 15hp johnson water tube help.

that diagram shows that water comes out threw the exhaust tube also. i just dont want to pull the power head and the gromet is good and the extra water coming back down is normel. thanks

No problem, I think the diagram is demonstrating thermostat open water flow.

http://www.sschapterpsa.com/ramblings/water_circulation.htm

Go here and have a look. The Machinest who is a member on this forum manages that website, he knows these motors inside and out, he says when connecting a garden hose to the water tube:

Using this you should get a water stream out the pee hole & you could also get a pretty good flow of water down the exhaust housing tube if the thermostat has been removed, which would be the total of the exhausted cooling water (minus the pee hole water).


Does it have a stat and does it work?

I'm sure someone else will be along to verify.

 

[SMOKEHOUSEROB]

Re: 1978 15hp johnson water tube help.

No problem, I think the diagram is demonstrating thermostat open water flow.

http://www.sschapterpsa.com/ramblings/water_circulation.htm

Go here and have a look. The Machinest who is a member on this forum manages that website, he knows these motors inside and out, he says when connecting a garden hose to the water tube:

Using this you should get a water stream out the pee hole & you could also get a pretty good flow of water down the exhaust housing tube if the thermostat has been removed, which would be the total of the exhausted cooling water (minus the pee hole water).


Does it have a stat and does it work?

I'm sure someone else will be along to verify.

i am note sure if it has a stat how hard is it to check and what is needed ? sat the video thanks.

 

[Rick.]

Re: 1978 15hp johnson water tube help.

You would have to pull the back stat cover plate to see if you have a stat in place and you would have to test the stat in hot water to see if it functions correctly. Time consuming and a new gasket would be required. To remove it you also need to remove the cowling latch for clearance purposes.


bktheking: Thought to ponder here. I have no idea what water pressure the pump is capable of producing but I would bet it is low especially compared to the pressure in a hose with city pressure. In my town the pressure of the distribution system is approx. 100 PSI. So, I'm just wondering if the water pressure alone (connected to town pressure) could cause the stat to unseat and thereby provide water flow even though the stat isn't up to temperature. This would not be the first time I've gone off track in my thinking but would be interested to here your thoughts. Although I've connected to the water tube myself introducing that kind of pressure to a motor seems almost inhumane to me. Rick.

 

[bktheking]

Re: 1978 15hp johnson water tube help.

I would never put 100psi if pressure through the system unless i were to pull the thermostat out for fear of blowing something out. Normal PSI for these things is low I would imagine, no where near 100 psi. If the pressure were low and the stat closed the only water to be seen would exit out the telltale as it would have no where else to go. When they are at operating temperature the stat opens allowing water to flow through the entire system and back out the exhaust housing, that would be my logic. Water leaking from the exhaust at low pressure may be an indicator that the grommet isn't sealing properly or the base gasket is cracket/missing. If the motor isn't overheating then take your chances. Those grommet's can collapse causing water flow issues and if it's never been replaced chances are after 30 years it has deteriorated somewhat or may be missing.

 

[Rick.]

Re: 1978 15hp johnson water tube help.

So all things considered, I would agree with bktheking. You need to check and see if the stat is installed or not. It is rather common for them to be removed and not replaced although I would not recommend running it for long with out one. If the stat is in place, test it's operation. Best of luck to you. Rick.