2004 Optimax 115 for 72 Seafari 20

[McGillicuddy]

Happy New Year!

Found a 2004 Optimax 115 for fair money w/ smartcraft controls/gauges. 350 hrs.

Questions:
1. are my rotary ride-glide steering and Commander controls compatible with the Opti?

2. does the usage printout show break in chronology or just hours at each rpm range?

3. general opinions on the year or motor model?

4. What is fair price range for such a motor?

Thanks!

[Fr. Frank]

Great find! Your controls and steering will work just fine. You may need a new key wiring harness, though. I don't think the cannon plug connectors are the same.
I don't recall what the difference was, but when I bought my 90 Opti, I had to specify whether I wanted a SMARTCraft version of the engine, or mechanical/analog version. I chose the manual control version. (The SMARTcraft engines actually say SMARTcraft on the back of the cowling in '06)
So if this 115 was being run with SMARTcraft controls, you may have to do something to convert it. I'd ask Tim about that. (Bigshrimpin).

A quick search on Craigslist and ebay found 6 Mercury 115 Optimax motors between 2003 and 2007 model years. Lowest asking price was $3150 for an '05 with over 1000 hours on it. Highest asking price I found was $5300 for an '07 with under 100 hours.

NADA says $3130 avg. retail for an '04 115 Opti.
BoatUS says $3370 avg. retail for an'04 115 Opti 20" non-power steering with a saltwater history, $3510 for a freshwater motor.

So, (going out on a limb here), $3,000 to $3,500 is my guess.

[McGillicuddy]

Thanks for the input, Fr. Frank.
Happy New Year! May the dawn of a new decade bring grumpy grouper and plenty of water time.

Price is right between the NADA/BUS numbers you mentioned.

I have a call in to the resident Merc Wizard of MA and CSC.

A few more questions for you when you have the time:

Is your 90hp a 20 or 25" shaft. How does she sit(wet feet without plugs) in the water?

Did you move batteries forward? And what are you using for a starting battery - my understanding is that these motors require 1000 MCA or 750 CCA?

Do these motors really sip the gas at trolling or idle and lower "hunting speeds" (say 2500 to 3500rpm or 15 to 22 mph). I've heard silly stuff like 8-9 mpg at 1000 to 2000 rpm... T/F?

The irony is that this motor is currently on an SF20 that I nearly bought in 07 when I found my Seafari. Almost bought both at the time just to get the boat and motor that I wanted...Present owner is looking for a 175 hp class Merc, like an XR2 or an XR4.
Full circle, baby...

[Fr. Frank]

My 90 is a 20" shaft.

Yes, if I take out the deck drain plugs, my feet will get wet.

For a starting battery I have a single group 29. I used to have two group 24's, but twice I had trouble starting because of the lack of amperage. If you don't have the juice, the motor spins, but no fire.

My battery is in the original battery box at the starboard corner of the hull and transom below seat hatch. It just barely fits because of it's large size.

According to my mechanic, his reading of the computer says that at 1200 rpms (about 4.8 mph) I am burning about .65 gallons per hour, or about 7 mpg, not the 8-9 mpg others have reported. On the other hand, I get just over 5 mpg at cruise of 24-25 mph and 4500 rpms.

I fall off plane at about 19-20 mph and 3500 rpms, even trimmed down. I really need trim tabs.

From experience - if you don't have 900 cranking amps available the computer on the Opti will not allow it to fire. As FrFrank said - it will turn over but not fire. You have to have a good cranking battery. And if you plan to anchor and fish offshore, make sure your cranking battery is isolated from your "other stuff" battery. Trust me - that other stuff will draw the battery down enough to prevent the Opti from firing. Been there, done that, been helped in.

[castalot]

From experience - if you don't have 900 cranking amps available the computer on the Opti will not allow it to fire. As FrFrank said - it will turn over but not fire. You have to have a good cranking battery. And if you plan to anchor and fish offshore, make sure your cranking battery is isolated from your "other stuff" battery. Trust me - that other stuff will draw the battery down enough to prevent the Opti from firing. Been there, done that, been helped in.

are you kidding me i would look into a different motor i don't know i would trust it drifting around rips or night fishing are all new motors like that

[McGillicuddy]

Thanks again, guys.

Sounds like I better start saving for trim tabs and reconsidering the "vortex."

When I re-wired I set-up separate "starting" and "house" batteries using a Blue Sea Systems ACR/SI ("add a battery" unit). I've been very pleased with the system thus far. I'm ready for a new starting battery anyway, so that $170 upgrade is accounted for. If I get this motor I'll probably go with a Deka group 31 AGM. Or whatever offers 1000 cranking amps.

Required starting amperage aside, are there other concerns about the 115 Optimax?

I tend to think I can keep my old steering, but the motor comes with its own ignition harness so I imagine that changes out.

Does anyone know if my old Merc Commander shifter controls would be compatible with the Optimax?

Thanks again.

-Gillie

[Fr. Frank]

The Optimax uses the same Merc control cables that have been around for 52 years. So yeah, your MerCommander controls will shift and move the throttle.

BTW, since going to a group 29 battery, I have had no problems with the Optimax starting. My group 29 battery says "965 CCA". The battery I have hooked to my diesel generator at home is much bigger, and says "1475 CCA". It weighs 120 lbs, though. With my twice-rebuilt back, I can't move it without a shop crane, otherwise I would have used it.

are you kidding me i would look into a different motor i don't know i would trust it drifting around rips or night fishing are all new motors like that

I did learn this the hard way - my Merc mechanic learned me up on it when I took it in to him after being helped back in. This was a 1999 200, so maybe something has changed in 11 years. I have different boat and a 150 ETEC now with two batteries with a Perco switch. I don't know if it has the same cranking amp requirements as the Opti, but I am cautious anyway. I start on battery one and head out. When I get to my fishing grounds, I switch to battery 2 to anchor, troll or whatever. Runs radio, GPS, bilge pumps, baitwell, etc. Then I have battery one ready to crank at full charge again because it charged all the way running out - sometimes a two hour run. If battery two won't crank it to head back in, I can crank on battery one, then switch to "both" and run back in, charging both batteries. I also have an on-board charger system and I charge both of them the night before I head out.

But - to be honest, I have never had a situation where either battery would not crank the ETEC, even after a day of fishing. Maybe I am over-cautious with what I do, but I sure don't want to be stranded again. Maybe someone else knows the ETEC requirements? I can't find anything in my owners manual that covers it.

[Bushwacker]

One of my 2 batteries has been weak for last year or so and never comes up to more than about 50% of max capacity, I think about 12.4 volts, unloaded. I always run on it and keep the other one in reserve. My E-Tec always lights off within 1 revolution with the weak battery. I think it's started down as low as 12.1-12.2 volts; can't remember exactly, but it's never failed to start.