20' SeaCraft re-power
 

This past week was awesome. I scored a good deal on a Suzuki DF150, got it shipped to me and installed all within a week on my 1986 20' SeaCraft. The previous motor was a 225 Mercury Optimax. I was originally looking for a new (inline 4) F200, but there aren't any used for sale and a new one just didn't make sense for the amount of money they are vs. the boat it was going on. Once I gave up on the F200, I quickly stumbled across a brand new 2012 DF150 from Central Marine in St. Petersberg. It has been on the showroom since 2012 and came with 6 years warranty! The initial performance results are as follows:

Running 3x15x21 Solas Prop
Motor mounted all the way down
1 person and 64 gallons of gas

3500 RPM 22 MPH
4000 RPM 27 MPH
4500 RPM 33 MPH
5000 RPM 38 MPH
5700 RPM 43-45 MPH

I'm pumped about how quiet this motor is. I still have to make some adjustments. The throttle is too jumpy to me, but maybe that is the Suzuki controls. The motor will also be coming up 1-2 holes. From there I will start working on some other props.

From this:
https://lh6.googleusercontent.com/1m...w255-h191-p-no

To this:
https://lh5.googleusercontent.com/-_...w282-h211-p-no

And then:
https://lh4.googleusercontent.com/4_...w160-h211-p-no

https://lh4.googleusercontent.com/mC...w160-h211-p-no

https://lh6.googleusercontent.com/1n...w283-h211-p-no

What was wot with the 225 opti and how many mph did it drop by going down to the 150? Just curious cause I am thinking of putting my 225 on my bracketed 20 sceptre. Also what Pitch prop were you running on the 225 @ what rpm wot?

WOT with the 225 Opti was 54 MPH consistently, turning 54-5600 RPM swinging a 21P Tempest Plus. So I have lost about 10 MPH on WOT. I knew I would lose some speed, but am excited that 45 MPH is within reach and I do think with some motor mount adjustments and maybe some more prop switching I will get better. I am currently running a 21P on the Suzuki as well.

Here is a list of other props, that I tried with the Optimax:

Mirage plus 21p: plugs out on prop
3800 rpm 33 mph
4200 rpm 35-36 mph
WOT 53 at 5600 rpm - not hitting the rev limiter with this one

Tempest Plus 21p:
3800 rpm 35-36 mph
4200 rpm 40-41 mph
Wot - its weird because I had 6 people in my boat and got up to 54 mph at 5200 rpm. But with just my wife and I, we get o 52 mph at 5600 rpms.

Thanks for the info... Good luck with the sukie

Would be great to know some fuel burn numbers with that motor. Seems like a great match for the boat. Good luck!

Yeah I hope to have nmea data coming through my garmin in about 2 weeks. Will keep you posted. Also, considering a Merc Enertia Eco prop which might be even better.

Great motor choice that should last you many years. 5700 seems a little low for max rpm. A pitch getting you to 6100 lightly loaded should get you better speed WOT and at cruise. In the end I bet you get at least 4 nautical at cruise.