20' Master Angler Repower

[Cptn5245]

So with the help of members here and local mechanics, I decided to go with the 115 hp Mercury 4 stroke with the Command Thrust lower unit. The motor is a little lighter than the Yamaha, highly rated by local mechanics and was about $1500 less than the Yamaha. The dealer will use the old motor for parts and compensate me for that as well.

We are going to try to use the prop off the 150 two stroke Merc we are taking off. If the performance is lacking, we will explore other props.

Brought the boat in on Friday and should have it back this Friday. Will let you know the results. Thanks for all of the help, greatly appreciated.

[fishstu]

I replacing a 150 mercury 2 stroke on my 2001 SC 20 Master Angler - the same boat as yours. Still undecided - will like to hear how you like the mercury 115 4 stroke.

[Cptn5245]

Just wanted to give you an update, boat is running great. We have gotten thru the 10 hours break in period.

Top speed has been 29.5 knots at 5560 rpm with full tank of fuel and a passenger. Cruises nicely at 4000 rpm at about 18 knots. Can stay on plane at 15 knots 3800 rpm or so. Definitely going to add trim tabs as she does porpoise at times.

[JohnC]

I have read others on this forum with the same 115 Merc getting better performance that what you are posting. I believe 72Potter posted numbers over 40MPH. It may be a good idea to do a search and reach out to someone with the same boat/motor. I know mounting height of the motor and prop selection can change your performance significantly. Use the forum search and type in "Command Thrust" (with the quotes). Good luck

[Bushwacker]

Most dealers seem to mount the motors too low, so it's worth checking to see if the AV plate is up above solid water when you're up on plane. If it's too low, you may be able to pick up 2-3 mph by raising motor a hole or two!

[Cptn5245]

Bushwacker and JohnC,

Thanks for the input, I will check it out. We have been running it with a full tank of gas, 70 gallons, my 300 lbs and my son at 225.

[JohnC]

I have less experience on the 20 than many on this forum (mine is still under construction) but they seem to handle a balanced load pretty well, as long as it isn't too far astern. It may sound strange but weight that is forward or in the center of the boat seems to improves the ride while weight that is too far aft is detrimental. I sometimes use a friends 20SF with 225 Opti on the back so maybe it's not that way for boats with a lighter outboard - I can't say. In any event, me and my dive buddy weigh in not much different from you and your son and the 20 doesn't seem to care much (as long as we don't both stand in the corner). We can add 2 sets of dive gear and 4 or 6 tanks in the bow and it cruises very comfortably.
I just hope you can get the most out of your outboard - It really seems to pair nicely with that hull. when I am finished with mine I will likely power with the same motor.

Below is the quoted speed I saw before - not sure if the quote feature will work in a different thread.

Originally Posted by 72potter20

is that a 150 or 115?

My 115 hits 44-45 mph routinely. I saw 47 once in ideal conditions, wind at my back and just me and a quarter tank of gas. That was without the t-top. You?

[Beaver]

When I first got my 18 it was porpoising (even with a light 3 cylinder 2 stroke outboard). I raised the motor up one or two holes and it went completely away. As was mentioned, you may want to try playing with your engine height. A hole or two can make a big difference.