25 Johnson

[Mark Noteware]

I have water flow at idle speed and as motor approaches about 3000 rpm, the water flow from the exhaust ports stops. Tattletale keeps flowing.<br />Now the weird part..... I have replaced the water pump and still have the same problem, and I have replaced the thermostat and still have the same problem. An old sage told me to check the head gasket as if there is a break between the compression and the water jacket, the exhaust pressure could possibly restrict the water flow. This has been replaced also. Any ideas ?<br />Thanks in advance.<br />Mark

 

[angus63]

Re: 25 Johnson

What year? What model? Welcome to the forum!!

 

[Mark Noteware]

Re: 25 Johnson

Originally posted by angus63:<br /> What year? What model? Welcome to the forum!!

 

[Mark Noteware]

Re: 25 Johnson

Thanks.<br />1989.<br />Manual start.

 

[Mark Noteware]

Re: 25 Johnson

My mistake... it's a 20 hp., not a 25.<br />Mark

 

[angus63]

Re: 25 Johnson

Not sure, but I believe that will happen at higher rpms because the thru the hub exhaust has a venturi effect and draws the cooling water out of the hub only at high speed. Please check with someone more knowledgable with your specific motor. Do you know someone with a similar motor that you can compare flow with?<br />Good Luck

 

[Mark Noteware]

Re: 25 Johnson

Thanks for the info. I'll have to make a comparisson to another engine.<br /><br />Mark