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BP1330
04-01-2003, 05:08 AM
I am trying to find the max RPM for a 1981 175hp Mariner outboard. And also prop size. Any info of links would be greatly appreciated.

Boat Racer
04-05-2003, 12:58 PM
Need more info. Like boat size, and any mods to motor....
Unless you work on the: port timing, exhaust & heads, your max. powerband will be at the factory revs...
One last thing, cutting the heads, will make it a little stronger. And it's pretty simple to do, but I 'd recommend (1)pulling the can and drilling holes in the mid-section(2) increase the jet size by .002
[ April 05, 2003, 01:03 PM: Message edited by: Boat Racer ]

BP1330
04-06-2003, 07:16 AM
Its on an 18' Nordic. No extra work stock engine. I am just looking for the red line.

Boat Racer
04-06-2003, 11:40 AM
I 'd recommend (1)pulling the can and drilling holes in the mid-section(2) increase the jet size by .002 [/QB]And play with prop size + or - 2pitches!!!!

Boat Racer
04-06-2003, 11:41 AM
http://www.***boat.com/image_center/data/500/344motorplate.jpg
[ April 06, 2003, 01:01 PM: Message edited by: Boat Racer ]

Tom Brown
04-06-2003, 12:14 PM
BP1330:
Its on an 18' Nordic. No extra work stock engine. I am just looking for the red line. The red line will be 5500 but it will be no problem at all to occasionally spin it to 6K. :)

Tom Brown
04-06-2003, 12:29 PM
My manual shows that the 2.0 liter 1981 - 175 hp Merc should turn 5300-5800 at WOT.