No Redline

marc5959

Cadet
Joined
Jun 11, 2023
Messages
22
Hey guys, just wondering why there is no red line on the tachometer in my ski boat?
 

dubs283

Vice Admiral
Joined
Jul 27, 2005
Messages
5,322
Generally speaking an inboard engine should run around 4500 rpm wot

Specs differ among boats/engine manufacturers
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,080
Years back, I used some red paint, small pointed brush and some masking tape to add my own !! Being very visual was more noticible than trying to read small numbers !!
 

marc5959

Cadet
Joined
Jun 11, 2023
Messages
22
Years back, I used some red paint, small pointed brush and some masking tape to add my own !! Being very visual was more noticible than trying to read small numbers !!
Is there a way to figure out exactly what my redline should be with my specs, boat, motor, prop? I get on plane easily around 4000, cruise around 2800, tach limit is 6000
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
49,538
Is there a way to figure out exactly what my redline should be with my specs, boat, motor, prop? I get on plane easily around 4000, cruise around 2800, tach limit is 6000
look at the factory literature for your motor (we do not know what you are working on). that motor will have a WOT window of X RPM to Y RPM
 

marc5959

Cadet
Joined
Jun 11, 2023
Messages
22
look at the factory literature for your motor (we do not know what you are working on). that motor will have a WOT window of X RPM to Y RPM
Don't have any literature, bought boat used, no manual, you think a manual that I can download will have that info, 1997 Maxum Bow Rider 19' Merc 4.3 LX Gen+ engine. 2 barrel carburetor 190HP
 

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,080
Adjust your prop to reach max wot rpm with the lightest load you ever run, then when you run a normal load you will be good to go...that is how I have done it for years!!
If you tow toys or have large loads on ocassion, then have a spare prop with 2" less pitch to swap over.
 
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