Help!
I have a 2000 Lund 1700 Fisherman with a 2000 150 Optimax. This boat is new to me and the motor is new to the boat. Currently I have a Ballistic 3-blade stainless prop with 17 inch pitch. Normally loaded this configuration will easily redline the motor, something above 6600 on the dash tachomoter. (There is a shrill electric alarm that goes off, but the motor doesn't shut itself down like I expected.) The top speed is 49.5 mph on the GPS.
I have tried a 20 pitch Mercury Eenertia. This helped. The motor still redlines but the top speed is up to 50.5 and most importantly the bow comes up better. At cruising speed he Ballistic prop wouldn't lift the bow out of the water enough - the splash came from about the console and with the Enertia the spray comes from behind the driver's seat.
My primary goal is cruising at 30 to 35 mph. I want to do this with maximum efficiency. All suggestions are welcome.

You are on the right track.
If your engine rpms are too high, your prop is not loading the motor enough.
So, work with a prop shop or dealer and try a bunch of props in the 17-24 pitch range. It really doesn't matter if they are aluminum or stainless.
Get into the range that you need, and then you can dial it in for the final prop.

From the sounds of it, you have a strong engine for the boat. So, you may find that you have good luck with a 19,20,21,22,23, or even 24 pitch prop. You can try 3,4 or 5 blade props.

Also, try these tests with both a nearly empty boat; as well as a fully loaded boat.

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Also, consider the application that you will be using the boat for. If you are pulling tubes or skiiers, you might find that the 17 pitch ballistic prop is the perfect prop for that application. i.e. super hole shot, and the ability to pull a large load.

On the other hand, if you are running by yourself, with a light load and partial fuel tanks, and you really want to fly - you might find that you can actually pull a 24 pitch prop - if you have a lot of lake to get on plane. However, if you can get this prop up to 5300 rpm, you will be well into the 50+ speed.

Experiment, test, try, swap, and retest. This is one of the "fun" things about owning a boat.

Take care
REW

REW - thanks for taking the time to respond.

Starcraft 176 single console w/150 Opti, 2002 model. I run 21 Tempest Plus and 21 Trophy Plus with normal fishing loads, 23 Trophy Plus w/light loads and temperatures below 70 degrees outside. Motor is up 3 notches off the transom and bare hull weight is fairly light at 1140 lbs. Currently the 23 Trophy and 21 Tempest have me at 61-63 mph, r's with Tempest are 5700, w/Trophy it's about 5400. Trophy 21 runs around 61 at 5700. All props are balanced and blueprinted with added cup- Mark did the Trophy's and Boger did the Tempest. I run this rig for river fishing and have only about 100 lbs of gear in the boat, empty live wells, no kicker motor, etc.
Doug

If your looking for overall good performance I would look at the 19p tempest plus.

jclstrike - why the Tempest Plus. Isn't that a three blade prop? Do you prefer that to a four? Thanks for taking the time to respond.

If your looking for overall good performance I would look at the 19p tempest plus.

Me too.
That's what we put on the 1700 Fishermen w/ 150 hp that we sold ( a considerable number).

Me too.
That's what we put on the 1700 Fishermen w/ 150 hp that we sold ( a considerable number).


That is what I am running on my Pike 18, too ... a 19p Tempest Plus on my 150 Opti. It replaced a 19p Laser II.

The last specs I could find for the 1700 Fisherman were in the 2006 catalog. According to that, my Pike 18 and your boat are about the same weight but my boat is 4 inches wider and 9 inches longer.

The Tempest Plus gives me tremendous bow lift and gets more of my boat out of the water. The spray now appears to come from the stern of the boat instead of alongside seats 3 & 4 as with my Laser II. I get about 1 mph more (GPS) than the Laser II and it hooks up better for getting on plane, too. And, I don't get as much blow out during turns.

Great prop.

Hmmm, Tempest Plus 19p - when I used the prop selector utility on the Mercury site one of the suggestions was for a Tempest Plus 21p. I wonder if my tach is reading correctly. My dealer says the motor should "blow up" at 6600 rpm and I've seen 6800 on the tach - that's where the buzzer sounds, 68. Thanks for the suggestion.

I think you mean 5800 RPMs???? 6,800 seems a bit high for an opti! I do know the warning beeper on my 06' 225 Opti comes on a 5750!

Yes, unfortunately I do mean sixty-eight hundred rpm. I know it's supposed to limit well before that, but that's what the tach says. How do I check the accuracy of the tach? Is there some cheap/easy tool to use? My old dwell/tachometer only reads to 2000 rpm. Is there something that will hook up by clipping around a spark plug wire like a timing light would?

Hmmm, Tempest Plus 19p - when I used the prop selector utility on the Mercury site one of the suggestions was for a Tempest Plus 21p. I wonder if my tach is reading correctly. My dealer says the motor should "blow up" at 6600 rpm and I've seen 6800 on the tach - that's where the buzzer sounds, 68. Thanks for the suggestion.


Tom, I don't know about the settings on tachs for certain. But I have seen posts on this site that say there are multiple attachment spots for wiring on a tach. That is apparently meant to make a given tach work for all boats with all motors.

From the sounds of it, I would think you need to have someone make sure your wiring is hooked up to the proper receptors on the tach. My 150 Opti tops out at 5450 rpm on my Pike 18 with the Tempest 19p and was about that same level with the Laser II if I recall correctly.

Hey, thanks again. I have been checking around and I find there are several settings on the back of the tach - 4c 2p, 6c 3p, 8c 4p, 5p, and 6p. I'm guessing the 4c 2p means 4 cylinders 2 pulses, etc. Thus the 4c 2p would be for a 4 cylinder 4 stroke motor. The logical extension is that I need to "turn the pointer" to 6p neaning a 6 cylinder two-stroke that has 6 pulses per revolution. Does anyone know for sure?

Actually, the P stands for the number of alternator poles on the motor.
Your tachometer countes the number of pulses coming from the alternator tach lead.

You might check to see what your tach reads at idle.
Most outboard motors -- if the idle is set right and if it sounds right - idle at about 800 rpm.

See if your tach reads UNDER 1000 rpm at idle. If so - it is likely that your tach is set correctly.

To be sure, you can always have a marine shop put their tach on the motor - either electrical or a mechanical tach that contacts the top of the flywheel with the cowel removed.

From the sounds of it, I would surely get the tach checked and calibrated or reset if necessary - before making any significant prop changes.

p.s.
Note the following from Teleflex:

http://www.teleflexmarine.com/library/marinedirectory/TMTechCat-Instruments(v4_0)Tech%20Reference.pdf

This document indicates that your tach should be on the

3P switch setting.

The document indicates that your motors alternator has 6 poles.

Take care
REW

p.s.
The setting - should be - as you posted the

6c - 3p

Take care
REW

REW - thanks again. Yes, the tach must be right first. But here's a new problem. Since I started this thread I've started receiving several unwanted pronographic emails per day. Is there something I've done wrong in registering? Is there a tool for blocking these? My more tech savy son says this is what happens on message boards...
Best regards,
Tom

Tom,
If you don't already have - get some good anti virus software with its built in spam blocker.
Also, if you have windowns, make sure that you keep your windows firewall turned on.

REW

jclstrike - why the Tempest Plus. Isn't that a three blade prop? Do you prefer that to a four? Thanks for taking the time to respond.

sorry for being late...its a three blade...I tried a four blade and it didn't perform to my liking on my last boat so i changed to this prop. This 3 blade gives decent top end, nice out of the whole and does well under a load...

i can easily rev my johnson 140 to 6200 rpm with a 20p stainless on a 1700 fisherman. I would sure think a motor with as much snot as a 150 opti would be able to pull a 23p.

My previous boat was 1700 fisherman with 150 merc carb. The boat came with the 21p merc aluminum prop. Would not recommend it as if you turned your head the merc aluminum prop would blow out. Put on a turning point hustler 21p prop. While an aluminum prop, it is designed like a SS prop (vented, high rake...). Was a 53 gps combination for me.

The fisherman is a light, wide hull that is easy to get on top of the water with 150. Would not go down in pitch because other hull designs need that lower pitch.

My 2 cents.

With the 19 im turning around 5700 with 2 guys etc THe max rpm for my 175 Opti is 5750 and with me and no fuel etc I can get the boat over the max rpm. Performance wise I don't think I can do much better and going to a 21p for a few mph doesn't mean a whole lot to me.