What Did You Do To Your Boat This Week?

Ended up working on the old Mastercraft ski boat while in the Okanagan (5.7/350 TBI motor).

Started to give me some problems last week of the summer holidays. Th boat should be good for +45mph @ 4500rpm, but was topping out at less than 4000rpms with no load, and bogging down at lower speeds when under load (we discovered this when trying to pull me out of the water on a slalom ski).

Replaced the high pressure fuel filter (no effect), and replaced the spark plugs (some good effect), but ran out of time. Its 24 years old, but only has 400 hours on it. Even though it only gets 10-15hrs a year I'm pretty religious about fluid changes, but have let some of the other maintenance items slide. Next up are the wireset + cap/rotor - also going to buy an OBD1 scan tool. These motors are know for fuel pump issues (has a mesh inlet screen that gets clogged) - so that is likely coming off as well over the winter and will buy a fuel pressure gauge. Annoyed with myself that I couldn't fix it while still in the water.
 
Finally bit the bullet on a new prop. Enertia ECO 16x19P which was recommended by Alberni. I’ve been running a 14.5x19P regular Enertia prop. Was happy with performance but always figured the motor had a little more to give, hoping to improve fuel economy too.

Currently I get 2.4mpg average, cruising 28-30mph, which is about 12-13 gal/hr. So for a guy who puts on about 100hrs cruising every season, it should pay for itself in a year and a half… well see

Side note, the blades on a brand new prop are deceivingly sharp
 

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Finally bit the bullet on a new prop. Enertia ECO 16x19P which was recommended by Alberni. I’ve been running a 14.5x19P regular Enertia prop. Was happy with performance but always figured the motor had a little more to give, hoping to improve fuel economy too.

Currently I get 2.4mpg average, cruising 28-30mph, which is about 12-13 gal/hr. So for a guy who puts on about 100hrs cruising every season, it should pay for itself in a year and a half… well see

Side note, the blades on a brand new prop are deceivingly sharp
how big of a motor is that on? and boat or rough weight?
 
Finally bit the bullet on a new prop. Enertia ECO 16x19P which was recommended by Alberni. I’ve been running a 14.5x19P regular Enertia prop. Was happy with performance but always figured the motor had a little more to give, hoping to improve fuel economy too.

Currently I get 2.4mpg average, cruising 28-30mph, which is about 12-13 gal/hr. So for a guy who puts on about 100hrs cruising every season, it should pay for itself in a year and a half… well see

Side note, the blades on a brand new prop are deceivingly sharp
You definitely put some miles on. The optimum prop makes a lot of sense.
 
My buddy runs a yami 250 on his 22 sea sport and doesn’t get near 2.4mpg. Looking forward to your report once you have ran it for a while!
Gimme 2-3 round trips to Sandheads and I’ll have a good idea lol.
I can’t stand the googan show at the boat launches (No.2 and MacDonald) when all the rookies come out in Sept. I’d rather launch at Pitt Marina right by my place and come up the river (about an hour each way at 28 knots)
Now I have an excuse to burn the extra fuel.
 
Gimme 2-3 round trips to Sandheads and I’ll have a good idea lol.
I can’t stand the googan show at the boat launches (No.2 and MacDonald) when all the rookies come out in Sept. I’d rather launch at Pitt Marina right by my place and come up the river (about an hour each way at 28 knots)
Now I have an excuse to burn the extra fuel.
I’m running the eco enertia 16X17P on my Seasport 19, weighs 4500lbs plus or minus. It’s on my new Merc Seapro 225, 4.6L v8.
I’m getting 3.5-4.0mpg. Very happy with performance and economy.
Here’s a pic from the other day, running at 30mph, 8gph, 3570rpm….3.7mpg
 

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I’m running the eco enertia 16X17P on my Seasport 19, weighs 4500lbs plus or minus. It’s on my new Merc Seapro 225, 4.6L v8.
I’m getting 3.5-4.0mpg. Very happy with performance and economy.
Here’s a pic from the other day, running at 30mph, 8gph, 3570rpm….3.7mpg
That’s great. I should be similar overall but not quite as good, you would think.

If I can even get to 3mpg average I’d be thrilled.
 
I’m running the eco enertia 16X17P on my Seasport 19, weighs 4500lbs plus or minus. It’s on my new Merc Seapro 225, 4.6L v8.
I’m getting 3.5-4.0mpg. Very happy with performance and economy.
Here’s a pic from the other day, running at 30mph, 8gph, 3570rpm….3.7mpg
Curious, have you verified that ie tracked actual fuel usage vs miles travelled, or just trusting your gauges.

Because my gauges suggest I’m getting 2.6 to 2.7mpg average but I just carefully tracked my last month or so (around 700L of fuel worth) and as I suspected, it’s actually 2.4mpg.
 
Curious, have you verified that ie tracked actual fuel usage vs miles travelled, or just trusting your gauges.

Because my gauges suggest I’m getting 2.6 to 2.7mpg average but I just carefully tracked my last month or so (around 700L of fuel worth) and as I suspected, it’s actually 2.4mpg.
I’m just going by the Merc vessel view gauges. I believe they are all in US gallons.
 
Are you going by the Smart Craft gauge to get this mpg? Do they read in US gallons?
Yes they read in US gallons but I’m using that in my calc as well (3.84L) Also not confusing nautical miles with miles (x1.15) when applicable… but it just seems off. Not surprising. I’m a technology conspiracy theorist lol
 
I’m just going by the Merc vessel view gauges. I believe they are all in US gallons.
Just checked to make sure.
AI Overview
Yes, VesselView systems that display "gallons per hour" (GPH) use U.S. gallons by default, as this is the standard unit for marine fuel consumption in the United States and for the global market. The VesselView platform, developed by Mercury Marine, is designed for this market and uses common U.S. units of measurement, including U.S. gallons”

If you use imperial mpg it would be higher mpg as an imperial gallon is larger.
Conversion factor for us gallon to liters is 3.785
 
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