'71 60hp --> No water out, but staying cool

[karrick]

I finally go my boat on the water this weekend to test the cooling system. I placed some thermocouples underneath a head/cover bolt and ran the boat for ~1 hour and never read a temp above 140degF. Should I be concerned that I am not getting water flow out of the two relief holes at the base of the powerhead? Before the water trial I checked to make sure water was flowing (no blockages) through the powerhead and made sure it was getting to the T-stat. Unless someone has a good reason as to why I should worry about it, I'm gonna run it. <br />thx

 

[Joe Reeves]

Re: '71 60hp --> No water out, but staying cool

Karrick... The long housing between the powerhead and the lower unit (exhaust housing) contains a inner housing. The space between the two contains water to keep the outer housing from running red hot.<br /><br />Some engines whereas the inner seals on those housings are perfect will have the water pump fill that area with water even if running on a hose (flushette) but this does not pertain to all of the engines. When actually in the water and underway, you will no doubt see a difference.<br /><br />The purpose of those holes (exhaust relief holes) is to allow exhaust pressure to escape when in the water, otherwise the exhaust could not exit due to water back pressure via the propeller area. Also those holes are an escape for water when the level of water gains that height, otherwise it would be possible for water to gain entrance to the bottom cylinder.

 

[karrick]

Re: '71 60hp --> No water out, but staying cool

thanks for the quick response Joe!<br />