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1985 Outrage 18 running a 1985 Johnson 150, mounted two holes up.

I'm currently running an old 14.25x19p OMC SST. With a light load, I’ve seen 45mph at 5000rpm WOT in fresh water at 1140' elevation.

I recently borrowed a 15x17p SST for a saltwater fishing trip. Though there were 3 of us in the boat for most of the trip, my WOT test was done solo, flat water, but with the added weight of a 100lb kicker, 2 Scotty electric downriggers, fishing gear, 1/2 tank of fuel etc., I saw 45mph at 5500 rpm pretty easily. Fuel burn on this trip was noticeably better than the last time I did a similar trip with the same crew but running my 19p prop.

Though it worked pretty well from a speed and rpm perspective, is the 15x17p SST considered a good prop for an Outrage 18?

I ask as I’d like to get a 17p prop to use for fishing trips, and would like to know if I should be looking for a used 15x17p SST, or if I’m better off getting a newer design.

ASIDE: I like my boat’s handling much better without the kicker hanging on the transom. This has me convinced lighter power is better on this hull. When the time comes, I’ll look to repower with an engine that will troll slow enough to not require a kicker. At my current use, it would take me 20 years to wear out a new engine, so am not concerned about the trolling hours.

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If you don't mind spending $449., I would think an 18" pitch Mercury Enertia would be the ultimate prop for your rig. It should give you 47-48 MPH.

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Mark,
It's funny I just came across your thread. I run a 1989, 25' Boston Whaler First Generation Revenge that had twin 115 Yamaha Two Stroke Yamaha Outboards when I first bought the bought as the second owner back in 1997. As usual, corrosion ate the twin Outboards away & I had to repower. The year was 2003 and as with many others I bought a 2003 Yamaha F225. I have LOVED this motor and I LOVE the YAMAHA BRAND most of all for their "Turn Key Reliability".

Unfortunately this year I did have a COOLING PROBLEM WITH MY MOTOR which was due to the improper metal alloy that was used in the Exhaust System in 2000-2004 from what I understand.

At any rate, Yamaha was great in offering me Yamaha Lubricants & Fuel Additives ONLY BECAUSE I HAD VERY DETAILED SERVICE RECORDS of proper service & using only Yamaha products.

I love my Yamaha F225 and look forward to the day I can upgrade to a single F300 on a` Whaler Drive.

YAMAHA IS THE ONLY WAY TO GO!!!!!!!

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Mark -- I got your email. Super busy now. Let me reply here.

Yes, the SST is a fine prop for your boat. Normally, one would run a 19" pitch version, but because of your altitude and the motor's age, this 17" may be more appropriate.

The E-Tec 150 uses the same gear ratio as your current motor but has a slightly higher Optimal RPM range, so it may make use of a slightly shorter pitch prop, but because you are already using a shorter pitch prop, a single prop may work well for both motors.

Sure, try an 18" Enertia if you can find one. Also consider a 19" Mercury Laser II or a 17" Stiletto Advantage or Turbo 1.

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Thank you Larry and Tom. Your wisdom is appreciated.

The altitude boating is at the lake near home, when we are typically lightly loaded. We are always significantly heavier when salmon fishing on the west coast of Vancouver Island.

So it seems the value choices are the 15x17 SST, or the Stiletto Adv 17p.

Does the Enertia (or Laser II) have any particlular characteristic(s) which would make it worth the additional $180?

I'm new to this sort of fine tuning, and do not yet have a lot of experience with 18, but if I was to wish for anything, it would be more stern lift, less bow lift over my current setup.

When travelling on the outside of Vancouver island towards the fishing areas, I'm trying to go as slow as possible on plane due to sea conditions. This is when I'd like additional stern lift, if available. We usually travel with the three of us standing at the console.

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Mark,

I have a 1985 Evinrude 150. Same as your Johnson.

I have 3 props, all older OMC
19 pitch
17 pitch
15 pitch

I also have the Modification on my motor to reduce compression so the motor can run on Regular gasoline. This was an OMC Bulletin back in the day and have a sticker on the motor to show the Mod.
Not sure if you have the Mod or not but all it is, is a thicker head gasket to reduce compression.
My owners manual states to run the motor on premium instead of regular.
Does your manual say the same?

The 17 pitch performs best for my boat and allows me to reach the operating RPM's

The newer props are different today and not sure which one I would buy for my motor if needed.
Let us know which one you get and how it performs.

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Thanks Joe.

I recall your prop selection and engine modification and this, along with my WOT rpm with the 19" SST, inspired me to try the 17" from my friend, who runs it on his Outrage 22 custom.

I unfortunately don't have the manual for my engine, so don't know if the low compression mod was ever done. I will scour the engine for a decal when I get the chance. It does sound fine on the regular non-rthanol fuel we have here, and I have not noticed any detonation.

I've been reading a lot of old prop discussions this morning, trying to learn more about the suggestions made by Tom and Larry.

Clarification to my notes above about lift: I think part of the challenge is that the old OMC 150 doesn't trim down particularly low. At mariginal planing speeds, the boat wants to sit on step bow high or jump right on to plane and take off. This is the situation where I'd like to get the stern up and bow down to push more water to keep a more level attitude at a slower speed than I can now. I probably just need more negative trim, and expect I will get this when I'm able to replace the old 150.

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Hard to kill those old 150's.

Like the energizer battery bunny. It just keeps going and going.

Hard to justify $12k or so for a new motor when mine in running fine.

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I hear ya! My engine, though a little noisy, runs better now than ever with the new power packs.

I'd like the new technology partially for green reasons, partially for fuel economy, partially because they run clean enough to troll, and for confidence in reliability when we spend a few thousand on travel and lodging to go on a saltwater fishing trip. All these things, plus the fact I'm not always rational, contribute to me wanting to repower in the next year or two.

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Mark -- If you need to maintain plane at slower speeds, don't worry about negative trim, buy a good stern lifting propeller. More blade area and a larger diameter will contribute to stern lift.

Try a Mercury 14-5/8" x 17" Revolution 4. This propeller excels at holding a boat on plane at minimum planing speed, or even mushing along. It's not the fastest prop out here for WOT work, but for your situation, it might work very well. They are plentiful on the used market.

It's a big heavy prop though so you may want to use a Solas Rubex hub kit to soften the shift clunk.

The Rev 4 will tolerate a higher motor mounting height. The motor should be two, or maybe even three holes up with this prop. The higher motor mounting height alone will go along way to reducing bow rise.

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Thanks Tom. This is what I'm looking for, for our fishing trips, as we rarely run much more than about 33mph in optimal conditions. The offshore running is typically between 13-23 MPH.

Our use is so varied, that I think having two or more props in stock is the way to go. I likely need only consider that my prop inventory work well at a common engine height.

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Now that we know a little more about your conditions, I would seriously consider the Mercury 4 blade Vensura (used to be called "Offshore" until the Rev-4 came out). I have two friends who run them on their V-6 Yamaha powered Whalers, and they perform very well. One is a 19 Outrage II (same hull as the Outrage 18) with Yamaha 150, and the improvement in overall performance, ride comfort and planing at lower speed, was remarkable compared to the Yamaha SST. He has been running it for 10 years now and loves it. It is on a 6" setback Detwiler jackplate, and the anti-vent plate is running about 1" above water flow. No slippage at all, anytime. and the boat runs about 43 MPH top end (remember this is a much heavier boat than the outrage 18) Mercury specifically markets this prop for offshore center consoles up to 24'.

I know Tom does not like the prop, but in my opinioin it would be more suitable than the Rev-4, which I think is too large a propeller for a lightweight Outrage 18. And your engine gearcase would have a hard time handling it. I have experience with both of these 4-blades, and Rev-4 is for heavy boats with big HP. Twin Rev-4's are too much for my relatively light wieght Outrage 25 with 400 HP.
The Vensura is for more general use. On my classic Outrage 19 with single Merc 150, The Vensura was about 2 MPH slower, and exactly the same, as an aluminum Black Max. Both ran 45 MPH. With the Laser II, the boat runs 47 MPH.

I would definitely try to find a used one and give it a try. They are available in 17" pitch and up to 23". This prop would be my next choice recommendation after the Enertia.

For your offshore fishing on the Vancouver Island west coast, I would not recommend a Laser II. They are not good for slower speed running in big seas.