How to backflush...

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Hoyt79

Petty Officer 2nd Class
Joined
Mar 26, 2011
Messages
172
1972 50 HP Johnson...just wondering if there is a way to backflush the water cooling system? I think I may have a partial blockage in the system...it spits water out of the exhaust ports during any RPM combination above idle but very little at idle in the lake.
 
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Daviet

Fleet Admiral
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Sep 24, 2008
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8,958
Re: How to backflush...

Nothing easy, you could remove the thermostat and try to force water backwards through the engine. Is it overheating? I don't think you will get very much out of the exhaust ports at an idle. Water coming out of the exhaust ports is associated with engine RPM, water pump spinning faster.
 
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wilde1j

Vice Admiral
Joined
Apr 15, 2002
Messages
5,964
Re: How to backflush...

Or, if you have the LU off, you could blow water or air up the water tube. Pressure should dislodge anything in the water pasages.
 
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Hoyt79

Petty Officer 2nd Class
Joined
Mar 26, 2011
Messages
172
Re: How to backflush...

wilde1j said:
Or, if you have the LU off, you could blow water or air up the water tube. Pressure should dislodge anything in the water pasages.
Click to expand...

I may do that next time I have the LU off....I think it is working ok, I ran it for an hour solid on the river the other day with no problems, just would make me feel better to backflush it if I could somehow. I am going to limit the idle time on the motor, because it doesn't spit any water out of the exhaust ports while at idle, the prop is not spinning at idle so no water.
 
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Daviet

Fleet Admiral
Joined
Sep 24, 2008
Messages
8,958
Re: How to backflush...

The water pump is driven off of the drive shaft which is turning when ever the engine is running. Sounds like your pump is operating properly.
 
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