I was wondering about those Johnson outboard engines, I have a 91-V4 120hp engine, can you tell me what top speed should be on that type of engine, and does the difference in prop, original prop vs. stainless steel makes a difference in speed. Also does a tail on the the motor to help balance when running slows the boat down, any info would be helpful...

Boat type will have more to do with speed. Yes a whale tail will cost you some top end speed. Yes the right stainless prop will help top speed.

Boat Type,(91-Glasstream Bass & Ski),the prop is the original that came with the boat, any ideal what top speed should be, I'm only getting about 30-35mph on a good day with two people in the boat.What I want to do is increase the speed, but I want to make sure when I invest in that process, that I'm getting it right the first time..Does the carb have anything to do with this/

need prop size and wot rpms to come up with a recomendation

I have a 97 125 on a 17 foot Ranger Fish/Ski and have just gotten it up to 45 on GPS with two people in the boat. 22ish pitch SS prop.

I have a 92 Johnson 115 on 18' Nitro with "whale tail" and SS 18p prop that gets me to 45.

I will find out on the prop size,but I do know the RPM is supposed to be around 5500 or 5600. I haven't had the boat that long...

Thanks for the information, I have a 91 Glasstream Bass & Ski.I figured that it shoul'd at least do 45mph, A friend has a 85hp Mercury on a bass boat and he gets about 50, so I was trying to figure out how a boat with a smaller hp engine can go faster that my boat.. the only solution I coul'd come up with is, it has to be the prop I have which is the original that came with the boat, or that whale tale on the back.

Thanks for the information, I have a 91 Glasstream Bass & Ski,it's starting to sound like it has to do with the type of boat meaning manufacturer, maybe the boat is heavier or possibly the prop. Have you heard anything about the Apollo Prop, that was a recommended prop for that engine..

find ya a 20p Raker for the v4 engine. that will be the best prop for top end speed.

biggest problem you're gonna have is your boat ,being a fish/ski. You have alot more weight farther forward than most other bass boats, that's why your speed is not so good.
i am not sure you'll ever see much over 40ish, but it's worth a try.

I have a 17 ft Alum runabout, but has a lot of weight in it
including built in front and rear decks with tank live well
and 3 batteries running a johnson 120HP with 19P prop with a
cup. Very top with just me is 40MPH normal 35-37 tops I do
have tail on it. Part of it I think is the v4 120 eng has
a cast iron block and is about 100 lbs heavier than the alum
block 115HP Normal rpm is about 4900 top with the setup I have.

Thanks for all the good information, that why I really like this forum, it's a really good tool for the fisherman/boater..

Thank you for all your help and suggestions, do you know who sells those kind of props? if not, where do you suggest I begin to look for one?

go to steves post above and order from the "prop pimp" he da man on here for props.