What Is The Small Black 7/64" Vacuum Line For?

[MyName]

Can someone identify what the small Black rubber 7/64" vacuum line is connected for coming down about 1 foot on the starboard Right side of the Mercury 800 80 hp 1978?
It was cracked at the top where it was pushed onto the small fitting located behind the switchbox area so I cut the end and pushed it back on. However, where it connects about 1 food down, difficult to reach to see clearly. So before attempting to pull on that end with a long curved needle nose to pull it off and re-cut/replace along with a few of my choice ' Boat words' Is it a necessary thing, or another one of my 'fix what ain't broke' things, or not?

 

[racerone]

It is an oil recirculation line and it must be installed.

 

[MyName]

It is an oil recirculation line and it must be installed.

Hello racerone,
Thanks for the reply, however it is a two stroke, not jet & no oil reserve Injection, so that does not seem to me at this point to answer the delema. The line also has no sign of H2o, oil etc evèr passing through it. It's just my assumption it may be leading/connecting to the line for the PSI gauge that monitors the water pump Impeller pressure and the teltale peehole' What's your thoughts about this?
Regards
Stephen

 

[racerone]

It is an oil recirculation line.----You must replace it ASAP.-----And I certainly know that a 1978 Mercury is a 2 stroke !!

 

[Chris1956]

Gravity causes oil to settle in the lower main bearing. Pressure from the crankcase, forces the oil on the bearing, thru a brass one way fitting, thru the hose up to the top main bearing, to oil it.

 

[MyName]

This Is A Photo of The 7/64" Vacuum Line In Question

 

[racerone]

It must be replaced.----It is not a vacuum line.

 

[MyName]

.

Gravity causes oil to settle in the lower main bearing. Pressure from the crankcase, forces the oil on the bearing, thru a brass one way fitting, thru the hose up to the top main bearing, to oil it.

Thanks Chris,
It's good to hear from you again. It's been a while & you've helped me and others a lot. I was able to secure that little bugger, no split end where it connects at the lower point, yeah! You know what it's like getting a tool to some of those places, fingers/hands? No way!
Kind regards,
Stephen

 

[MyName]

It is an oil recirculation line.----You must replace it ASAP.-----And I certainly know that a 1978 Mercury is a 2 stroke !!

Yup yup got it, did it, Thanks racerone
Kind regards
Stephen

 

[MyName]

It is an oil recirculation line.----You must replace it ASAP.-----And I certainly know that a 1978 Mercury is a 2 stroke !!

 

[MyName]

Hi racerone, I just referred someone on Facebook to the iboats forum for help with his older 115 Mercury Outboard similar or same to what you had or have because you helped me so patiently and professionally to get my Mercury 800 Thunderbolt going long ago. I couldn't have done it without your help and also Chris1956. Thanks again.

Kind regards
Stephen
Aka iboats
MyName