Mercury 20HP Idle relief plate question

[mmf]

I have a 1980 model Mercury 20 HP, serial 5610105. Motor runs great
and pumps water good and a good pee stream. Motor does not run hot but I noticed it does not spit water from the two exaust ports on the upper drive shaft housing like my 1973 model 20 hp does. Is there a reason for concern here? I noticed on the exploded parts diagram for the 1980 model that there is an "idle relief plate" mounted to the bottom cowl at power head bottom. Is this plate supposed to divert water to the exaust ports at idle? Maybe my idle relief plate is not functioning correctly, anyone with experience on this plate?

 

[7920hpMercury]

Re: Mercury 20HP Idle relief plate question

This is the last year for the old 20hp design and I would bet that your idle relief system is plugged up with exhaust carbon/goop/oil. There is a plate screwed with 2 small phillips head screws to the mid section and 2 plastic tubes with holes installed just like your 73. Also if overheated in a past life, the plastic tubes can melt and plug it. Either way, exhaust can exit.