Mercury Prop Advice

[krono]

ESSENTIAL DATA REQUIRED:

1) Performance issue you are trying to correct: Planing (Holeshot)? I have an 18' fish and ski, and it takes it too long to plane when skiing. Boat will be used 80% watersports/20% fishing.

2) Current prop manufacturer, model, aluminum or stainless as a minimum. Mercury LaserII SS.

3) Current prop diameter and pitch (required): 3 blade, 22 pitch, 13.5" diameter.

4) Wide open throttle RPM and speed with an average load (very helpful): 5,200-5,600 on motor label...had it up to 5800 on water. Hard to tell top speed as speedo is not working. Guessing around 50+. Previous owner sez he had it up to 58 with just him on very flat water. Not sure how accurate that is...though.

5) Engine/drive make, model, year, and HP: 1998 Mercury 150 EFI w/oil injection. No jack plate, but has some sort of metal bracket reinforcement.

6) Boat make model, year, length and weight. VIP 180 18" Fish & Ski. NADA says it weight 1730 lbs (assuming w/o trailer). Also have 3 batteries, trolling motor, skis & accessories and about 900-1000 lbs of peeps on board.

 

[steelespike]

Re: Mercury Prop Advice

Too long to plane is a little vague. Is it minutes or seconds.
You do trim down for hole shot, right?
According to the tach your already overeving with a light load. My info is a max rating of 5600.
The easy way out is probably a prop change.
Speaking very basically a 4 blade ss prop in the same pitch should help hole shot and keep rpm closer to 5600. There are others more acquainted with larger horsepower setups they should chime in soon.

 

[krono]

Re: Mercury Prop Advice

Certainly not minutes. More like 30 secs when pulling a heavier skiier.

 

[krono]

Re: Mercury Prop Advice

Trim down also for hole shot. Heard a 4 blade would be good, but in a lower pitch. Thoughts?

 

[krono]

Re: Mercury Prop Advice

Also corrected prop diameter to 13.5".

 

[krono]

Re: Mercury Prop Advice

Anyone else care to take a shot at prop type, size, pitch to get? Also, the bow seems (to me) to be at an extreme angle when first trying to pull a skier...and motor seems to be bogging down...if that makes sense.

 

[krono]

Re: Mercury Prop Advice

Ttt

 

[QC]

Re: Mercury Prop Advice

This is kind of a fact of life with higher speed boats. Very hard to have a single geared entity that can run 58 MPH and also get decent hole shot. With that said, your 150 should have plenty of power. What you might need to consider is carrying a 19 or 20 inch 4 blade for skiing. Or even a 19 inch High Five. These props are fantastic for water sports.

BTW, a deepwater slalom skier, big ones especially, is one of the highest load items you will ever deal with. Many boats struggle, even reasonably powerful ones

 

[fishrdan]

Re: Mercury Prop Advice

Is your prop vented, or have changeable vent plugs. The vents allow the prop to slip more during hole-shot, RPM's come up on the outboard quicker and the boat get on plane faster.