How fast should I get?
 

I have a 1983 v20 with a 1981 150 Johnson. I have been working with the throttle/idle etc. and I was wondering how fast I should be going on this set up. We maxed out with 2 of us and no gear in a light 1' or less chop the other day at 34mph(non gps , this was the boats speedomoter). Is this correct or do I need to idle it up some? Thanks. Craigan.

I don't think the idle setting will change the top end. I would say you should be running about a 17" pitch prop for good performance. Try a gps. The boat speedometers are highly inaccurate. I had a 150 merc on my V20 and I maxed out at 42 mph with a 17" pitch four blade prop. There's a bunch of guys on here with your same setup. You should get some great feedback. Good luck.

Seaccrets right on all counts...w/ the right prop your V oughtta be in the low 40s and be able to cruise at around 30 or so...check your prop's numbers and see what you got...

Hey...where is Westville?...

It's just north of Camden, Sc. We're about 20 min. from lake Wateree. I grew up in Woodruff though and spent a lot of time in the spartanburg area.

ditto you should be in the low 40's light with a 17". theres no way you would turn a higer pitch unless you had a 4 stroke.

Like they said!!
For that motor.
19" for a real light loaded V.
17" pitch is about normal, full gas, 2 people full of a days fishing stuff.
Either prop, with that motor, should suck about 22gph at WOT but do between 41-43mph, if you got the motor at the correct height.