"Inno" wrote in message
oups.com...

This is a 4.3 Volvo Penta by the way, 190 hp.

This is my first boat with trim adjustment. I have been trying to
maximize speed according to the speedo w/o adjusting the throttle. So
you are saying ignore speedo and try to get the rpm up?

Can anyone explain in simple terms what the theory is behind trim
adjustment. I start off with the engine all the way down, right? Then
when I get onto a plane I raise it a bit? How much to raise it is the
mystery for me! Conditions on our small lake are usually fairly calm,
load is usually about 2 or 3 adults = 400 pounds.

Many thanks for all responses!


You have described the basic process. Get the boat up on plane and then
leave the throttle alone. Start trimming the leg out in small steps while
watching the tach (and where you are going!). You are trying to maximize
the engine RPM for that throttle setting with the trim. If you go too far,
you'll know it by hearing the prop start to lose bite and the engine will
start to race. After some practice, you'll be able to do it by ear.

Eisboch