I am building a 115hp Murcury Outboard the stripes are silver and red and
says oil injected. I was curious what year this motor is. Does this
powerhead have the boost ports in this year. I have two other motors. One
motor is on my boat 1984 90 hp brown stripe runs but has 90 psi
compression across the cylinders. and I have a good Mariner 115 hp
powerhead with 145psi across the cylinders and 115 hp carbs which I was
going to drop on the 90hp lowerunit. Is the lower unit have a different
exhaust chamber or will the 115 hp powerhead work fine with the 90hp lower
unit. If there is any one out there to give me some advice I'ld appreciate
it. I have not been able to find much on porting and performance tips
online.
I have been building two stroke and four stroke race engines for
motorcycles for 30 years. This is a fun new direction. I had a blast this
summer with an 18'Chris Craft Caper with the tired 90hp. Know its time to
freshen things up to make it realy fly.
Thanks,
caperman

isnt your mariner a four cyl.and the 90 a 6 .im in the process of getting
115merc sounds like the one you described which is supose to be an 86.
best to match the serial # to year.ive seen this on another web site.as
far as the boost port this was on the150 hp

[posted and mailed]

"caperman" wrote in
lkaboutboats.com:

I am building a 115hp Murcury Outboard the stripes are silver and red
and says oil injected. I was curious what year this motor is. Does
this powerhead have the boost ports in this year. I have two other
motors. One motor is on my boat 1984 90 hp brown stripe runs but has
90 psi compression across the cylinders. and I have a good Mariner 115
hp powerhead with 145psi across the cylinders and 115 hp carbs which I
was going to drop on the 90hp lowerunit. Is the lower unit have a
different exhaust chamber or will the 115 hp powerhead work fine with
the 90hp lower unit. If there is any one out there to give me some
advice I'ld appreciate it. I have not been able to find much on
porting and performance tips online.
I have been building two stroke and four stroke race engines for
motorcycles for 30 years. This is a fun new direction. I had a blast
this summer with an 18'Chris Craft Caper with the tired 90hp. Know its
time to freshen things up to make it realy fly.
Thanks,
caperman


You're on the wrong newsgroup for an Inline Six question.

There is a newsgroup totally dedicated to inline 6's care and feeding:

The NNTP server is: news.kraits.org and the newsgroup is:

bigweek.mercury-inlines

In Outlook Express use: tools/accounts/add/news and then follow the
prompts to join us there!

The Cap'n