Ehxaust relief

[wynjim55]

What does the exhaust relief look like, and where would I find it, on a 1978 Yamaha built 2 cylinder Mariner 55? What does it do?

 

[fastjeff]

Eases pulling it over when starting. Consists of holes drilled through the cylinder wall into the exhaust area.

Jeff

 

[racerone]

It is the exhaust that comes out above the water when motor is idlling.---------Saves the motor from having to push it all the way down to the prop.-----Look for the smoke at the back of the motor.

 

[fastjeff]

That's another definition. The usual reason for it--and Yamaha uses it regularly--is to ease starting effort.

Jeff

 

[racerone]

Exhaust relief above the water ( for better idling / starting ) has been used on Mercury / Johnson / Evinrude ------For , like well over 70 years.

 

[wynjim55]

Is the outlet found as part of lower unit or the mid section?

 

[fastjeff]

I stand corrected! You're talking about 'exhaust relief', and I was thinking COMPRESSION relief.

Look carefully in the photo and you'll see what a compression relief looks like--that tiny cut out above the exhaust port. Other motors have a hole drilled into the exhaust cavity to relieve the compression on starting.

Jeff