Venus/Merc 150 Setup

I have a Venus with a 92 Mercury 150 Blackmax all stock. 6 inch jackplate, 19" blackmax prop. What is the most I can see out of this motor and boat. I know I have nothing special in the way of the prop and nosecone, No low water pickups ect... My question is how high is the propshaft supposed to be in relation to the pad. Also I am pulling about 5300 rpm's with this aluminum prop, what kind and pitch prop do you suggest...and what numbers can I look at realistically with this boat and motor if I do the nosecone, and better prop. Was thinking of installing Boysen reeds, maybe taking off the airbox and installing some velocity stacks....a friend said this would help. btw I think it does somewhere round 60-65 with its current set-up.   Thanks, Scott



First off realize the Venus is probably my favorite Hydrostream. Just because it's different. Don't do any mods to the 150 as there is a bunch of things to do first. Also removing the airbox will cause a lean condition (without proper jetting) and so much for your motor (seize!). A nosecone will do nothing for you at the speeds you'll run so forget that. Put the propshaft about 2 1/2 inches below the pad. Find a 13 1/2 X  24 laser II prop (the inline/four cylinder prop not the V-6 laser series) and you should be in the mid to upper 60's with that combo. I don't believe you're there now as a 19 at 5300 is barely 50mph. Based on the info you've submitted that's all it would run. Solid motor mounts are the next thing on the shopping list. Next, trim for the steering wheel and a foot throttle if you don't have them. To gain anything that would make a slight difference on the motor side, would require a lot of cash and a porting job to the block. It would be easier to find a 200 on the used market. That would push you 75mph without breathing hard. Lastly, any stainless prop 22-24 pitch would be worlds better than the 19 aluminum. If your rig is going 60+ already then the 19" prop is not a 19 or your tach is severely off. Try the 24 laser II if you keep the 150. 




Please submit whatever questions you have to  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Mark C.


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