posted 02-11-2013 10:18 PM ET (US)        

Stiletto 14.25 x 19
- The boat rode with the highest nose attitude with this prop.
- With the angle the boat was riding, I felt the "V" portion of the boat was not doing much, most waves impacted more towards the mid-line of the boat, thus the ride suffered a little bit. When I say that, the ride wasn't harsh, it just gave me the feeling that if the boat were angled differently it would be able to cut the waves better.
- Good cruising speed numbers
- With the boat very heavily loaded (4 guys, lots of ice, fishing gear, down riggers, gear, rods, etc.) the boat struggled to get on plane without the trim tabs.
- The prop did seem to over a lot of trim angle by trimming the engine.

Vensura 14.25 x 19
- Limited time to test this prop
- Complete opposite of Stiletto. This prop made the boat ride as if it was glued to the water. So much so that the boat rode horribly in all trim levels that I tried. Up, down, it did not matter. I only face some small close chop, but the harsh ride was very noticeable. My girlfriend even commented and asked why the boat was hitting so hard.
- The motor seem to spin more easily, sounded less labored in the 3-4000 rpm range.

Mirage Plus 15.5 x 17
- This prop was sort of in-between the Stiletto and Vensura. I noticed that the low speed maneuverability with this prop was good.
- The boat was not "glued" to the water nor was it bow high, running angle seemed fairly level.
- Throttle response was best with this prop. Whether that was due to the pitch or the "grip" offered by it's larger diameter I do not know.
- My boat was able to run with the prop very heavily loaded without issue.
- Using the engine trim did not seem to make as much of a difference in ride angle as the Stiletto, but more than the Vensura.
- Though I do not have a fuel flow measuring device, the end of the day burn total did seem to be slightly higher than with the Stiletto.
- Though the pitch was decreased to 17, I did not lose that much in cruise speed.

Enertia 14 x 19
- Limited time to test this prop (one outing thusfar)
- Noticed right away that this prop made the boat ride very smooth. All of the impacts seemed softer.
- The entire boat seems lifted out of the water with having a high bow attitude.
- Throttle response was not as immediate (compared to the Mirage Plus). Again, I wonder if this is because of the pitch of the prop or because it does not grip as well when accelerating. It also has a much smaller diameter, smallest of the entire test group. With both props I was only able to hit very near the redline of the motor and no more.
- The cruising speed overall and especially around 4000 rpm was very fast.
- This prop gave me the highest top speed of the test group
- This prop surprisingly gave me the lowest minimum RPM to plane
- Very strange, the numbers are showing faster speeds trimmed down vs. trimmed up.

I'm am pretty settled on the Enertia. My only question is whether or not I will have to step down in pitch to an 18". I would prefer to have some better throttle response as I had with the Mirage Plus. Will it work like the Mirage Plus or will it bog down like the Stiletto?

RPM/Speed Numbers: http://i7.photobucket.com/albums/y277/Triton_38/1993%20Outrage%2022/ Outrage22PerformanceSheet2-11-13_zpsf7408bea.jpg

posted 02-12-2013 06:52 AM ET (US)            

quote:

---

So it appears either this Merc 200 EFI is very fast, or the Whaler Drive wastes about 60-75 HP when compared to Honda's latest and greatest.

---

posted 02-12-2013 07:38 AM ET (US)            

Stiletto : 53,2 @5500 for 46,7 actual perf (12.3 % slip)
Vensura : 56,1 @5800 for 47,1 actual perf (16.1 % slip)
Mirage : 48,5 @5600 for 45,8 actual perf (5.5 % slip)
Enertia : 55,2@5700 for 47,5 actual perf (13.9 % slip)

slip for the Mirage seems in the standard range for a SS prop. I'm a bit surprised for the other slip that are over 10%. I thought SS props had very little slip values. I've always heard Stiletto to have near 0% slip.

Perhaps I took a wrong gear ratio.

posted 02-12-2013 10:54 AM ET (US)            

LINK to Photo

I was told that due to the lower pitch and larger diameter, the Mirage should hold better at low speed.

Also in my original post, the trim down speed being faster than the up is for the Mirage and not the Enertia.

If the prop is vented will the low speed planing characteristics change? That is important to me and the Enertia seems to do it well, would be a shame to lose any efficiency there.

posted 02-12-2013 12:01 PM ET (US)            

From what I have seen of the PVS, I don't think it is particularly useful on propellers of moderate pitch used on boats operating at moderate speeds. I think PVS was intended to allow boats to use propellers of high pitch, say pitches above 22-inch pitch, to allow the boats to reach very high speeds, say over 50-MPH, but to avoid lugging the engine down while accelerating.

I suppose there might be some benefit to carrying a propeller whose pitch was slightly too high for good acceleration, letting the PVS create the rubber-band effect while the boat slowly gains speed, and then being able to lumber along at a plaining speed with the engines running at lower RPM. But the cost of that benefit seems to be this annoying rubber-band effect when accelerating. I also worry about the propeller becoming aerated and losing grip in rough water. The PVS seems like it was intended for bass boats to skim along in calm water at 85-MPH. I do not think it is likely to provide a fantastic solution to operating a 22-foot OUTRAGE in the ocean in large seas and the typical speeds you want to go in those conditions. I think a vented propeller in those conditions would have an annoying tendency to be losing grip.

posted 02-12-2013 12:12 PM ET (US)            

If you are trolling with the main engine, your trolling speed is now limited to a higher speed. You may not be able to slow down to the speed you want because of the high propeller pitch.

When maneuvering around the dock, your slowest speed might be too fast. I find docking is done much more under control if you can move at 3-MPH instead of 7-MPH as the slow speed.

If the goal is to have the absolute highest top speed, the PVS may help. The absolute highest top speed is not particularly useful to me. I find my modern outboard engine tells me its operating speed history; I am only at full throttle a few seconds of each day. I don't really find it an attractive trade-off to get another mile or two per hour of top speed if I have to fiddle with the throttle all the time because of the rubber-band effect of PVS. But, you might be different. You might like it.

posted 02-12-2013 12:46 PM ET (US)            

1. Ride quality
2. Cruising speed
3. Low speed planing ability
4. Fuel economy

posted 02-12-2013 02:20 PM ET (US)            

Is the boat not as responsive due to pitch/power or grip? The Mirage just felt more "grippy" when accelerating. I'm guess it feels like "grip" but is really the pitch.

posted 02-12-2013 02:42 PM ET (US)            

There has been a notion put forth that boat miles-per-gallon can be improved at cruising speed by using a propeller with a high pitch and letting the engine run at low crankshaft speed. This proposal tends to ignore a fundamental relationship between boat speed and engine power: to make a boat run at a certain speed requires a certain amount of power. We cannot reduce the amount of power by trying to trick the engine with a different propeller pitch.

As a corollary to the above, it has been suggested that having really powerful engines and then letting them run at very moderate throttle settings was way to get improved fuel economy. This proposal ignores a fundamental relationship between engine efficiency and throttle. Most engines do not run at their most efficient point if throttled down.

Finding a slight peak in overall miles-per-gallon may depend on aligning several factors. Influences from the engine, the propeller, and the hull will all come into play.

The engine converts fuel into power according to its brake specific fuel consumption (BSFC). We know that BSFC is not constant over all crankshaft speeds, loads, and throttle settings. If we had detailed information for a specific engine of its BSFC as a function of these three variables, we could try to pick an operating range for the engine at cruise where the BSFC was best. This is how a team of naval architects would design the propulsion system for a mega-ship like EMMA MAERSK. The engine burns tons of fuel every hour, so you want to be sure you are operating it at its most efficient point.

Unfortunately, there really is not data available about the BSFC of outboard engines, and it is really hard to predict how a 1998 Mercury two-cycle V6 outboard with simple fuel induction is going to perform at various throttle settings, engine speeds, and loads, with regard to its BSFC. In that regard, I would suggest that if overall fuel economy is really a big concern, get a Honda BF250 four-cycle; it will get so much better fuel economy that you will likely be stunned.

The next factor influencing the fuel economy is the efficiency of the propeller at creating thrust. This is not measured by SLIP. It is really hard to measure the efficiency of the propeller. I don't know any way to do it. We usually see the influence of the propeller combined with BSFC and hull influences, and it is hard to say that we can isolate the propeller. The only way to isolate the propeller is the way you have done it: to use the same boat, the same motor, the same test driver, the same conditions as much as possible, and change the propeller. I don't know if in your narrative you tell us about your observations of fuel economy in detail. I would compare the propellers by running the boats at the same boat speed, and then judging the MPG at that speed. As long as the engine RPM was about the same, you could probably conclude that differences in MPG were a result of the influence of the propellers. If there was a big difference in engine throttle or crankshaft speed, then differences in MPG might be due to BSFC influences.

The hull is also a factor. Some hulls may have a particular speed where they are really efficient. This can be influenced by weight distribution, trim, running angle, and so on. In the propeller comparison you should try to keep everything about the hull as uniform as possible. As you mention, with some propellers the hull runs at a different attitude or planing angle. Now the hull is influencing the MPG.

With outboard engines we are stuck with fixed-pitch propellers for the most part. The PVS system is a method for creating a means of psuedo-variable-pitch propeller by intentionally spoiling the propeller blades with aerated water. The problem is this effect is only available in a certain speed range. It only occurs after the boat gets moving forward with enough speed to let the exhaust come out of the hub, and then it stops once the boat reaches a faster speed where the exhaust is being pulled past the vents without escaping.

It may be possible that by experimenting with various sizes of vents, or using different combinations of vents, you could find something that worked to your advantage. I cannot predict this.

posted 02-12-2013 06:13 PM ET (US)            

On that basis, if a particular propeller was able to keep the boat on plane at a low speed, I would tend to think it probably was generating some stern lift.

The stated attributes of the ENERTIA propeller are mainly related to two aspects:

--the material used to manufacture the ENERTIA is special. The alloy was supposed to be protected by a patent. Initial announcements said a patent had been applied for to protect the alloy. I have not seen any more talk about the patent. I don't recall hearing about it. The alloy may be something different, but as far as I know it is not protected by patent.

--the special material allowed for the blades to flex under load. This never made sense to me because previously it had always been mentioned that blade flexing under load was a bad characteristic. Apparently on the ENERTIA it is said to be a good characteristic.

I have no argument with the theory that propeller design is something of an engineering art form. It is clear that Mercury has a lot of experience with propellers. My impression of the whole propeller business is that the people who make them talk in a strange language and use odd ways to describe things. I think they do this in order to obscure the real features of the propellers that contribute to good performance. If they just came out and said, "This works this way because we did this," then everyone would know what they did and could easily copy it. Instead the always talk about "un-obtanium" materials, and strange characteristics like bow lift, stern lift, or simultaneous bow and stern lift, and a lot of other hocus-pocus language.

posted 02-12-2013 06:20 PM ET (US)         

You have never been in my Outrage 25 with highly vented Revolution-4 props. With them, the boat is a completely different animal - it accelerates faster, goes faster and rides much better. Back then, I was still using the original 1989 Laser II props, now long obsolete for large boats like a 25 Whaler, and no longer recommended by Mercury for my application. Blade area on the Lasers is too small for an application like a 25 Outrage. But back in 1989, that was Mercury's best recreational performance prop, with fixed vents before PVS, and Mirage props (Mirage Plus not yet out) were only for stern drives, for which they were originally invented. So your venting comments are from a zero real life experience as far as I can tell, since you use solid vent plugs on your own Mirage Plus. As a matter of fact, most Mirage Plus applications require solid vents because of slippage problems. I have never seen a boat with vented Mirage Plus propellers. Early Mirage's did not have the fixed vents, and the current Quicksilver equivalent does not either.

As for Mercury's vent plugs, on a high tech, highly raked prop like the Tempest Plus, Enertia or Rev-4, they can be of value, which is why they are there in the first place. Since one has this valuable option (that no other brand of propeller offers), why not try it. It's a cheap and easy experiment, and the solid (closed off) plugs are always there as a back-up.

I have noticed that on larger center console boats, with twin or triple Verados, the Rev-4 and Enertia props are run with solid plugs. But that is probably because the supercharged Verados have instant throttle response and faster more powerful low end acceleration than 2-strokes. So they don't need the blade venting that the 2-strokes do. It takes a LOT of power to turn my highly raked, 4-bladed Rev-4's in 21" pitch. They actually run like 23's. Take a look at these large props - most gearcases can't even handle them:

http://smg.beta.photobucket.com/user/lgoltz/media/Outrage%2025/DSCN1464. jpg.html?sort=3&o=28#/user/lgoltz/media/Outrage%2025/DSCN1464.jpg. html?sort=3&o=28&_suid=13607084472510725645387877184

Note that with these, or an Enertia, trim tab steering torque anodes can't be used on most engines. A flat plate anode is required.

The only way venting will hurt low speed planing is when you are over-vented. Actually, that is what determines how much venting you can take. When low speed planing gets worse, reduce vent size, but not until. On my 25, the super-vented Rev-4's hold plane for low speed cruising the best of any prop I have tried. The boat will cruise along all day at 2000 RPM and 20 MPH. 22 MPH is ideal for an easy ride with barely audible engine sound.

On my classic, easy to plane Outrage 19 hull, with 150 Merc and 19" Laser II running large vent plugs, I suspected low speed plane was too high. So I switched to solid plugs, and low speed plane dropped about 3 mph, with no loss in acceleration. So in that instance, I was needlessly vented. I am going to try an Enertia prop on this boat this season.

Venting is the same as propeller choices - experiment to find the best solution, like LittleBlue has already done.

posted 02-12-2013 06:30 PM ET (US)            

Also, thanks for agreeing with me that the PVS vents should be tried. I think I already said that two or three times.

Larry, you are right that my experience with PVS-vented propellers is limited. I have not tried them on my MIRAGEplus. Although I know a lot of people using Mercury propellers on their moderate speed Boston Whaler boats, and I have driven their boats from time to time, you are the only person I know who uses the PVS vents. I know you have five boats, but I am putting you down on the survey as one person who uses PVS vents, not as five people.

posted 02-12-2013 07:46 PM ET (US)            

I have tried a 20-inch Raker and it is too tall for four people onboard. An 18-inch Raker is great for when I am going to have a full load of passengers and fuel.

I may have to try an Enertia based on your report. Thanks.

posted 02-12-2013 09:44 PM ET (US)            

"Throttle response was best with this prop. Whether that was due to the pitch or the "grip" offered by its larger diameter I do not know."

L H G describes the MIRAGEplus:

"As a matter of fact, most Mirage Plus applications require solid vents because of slippage problems."

I have never seen any sign of the MIRAGEplus losing grip on my boat. One of the reasons I like the MIRAGEplus is its ability to run so well and stay so well hooked-up in the aerated water that is found in my boat hull's wake. (By the way, this is another reason why I don't think PVS vents are necessary for my boat. There is a lot of aerated water around the propeller already, coming off the hull due to the set back of the engine about 2.5-feet and its elevated mounting height compared to being on the transom.]

From the comments of LittleBlue, I infer he is not experiencing any slip.

Perhaps Larry could explain on what basis he has determined that the MIRAPGEplus suffers from "slippage problems"?

Re fuel economy:

posted 02-12-2013 10:06 PM ET (US)            

A few characteristics for the Enertia that I missed.

- The slow speed control was not good at all. Reverse/maneuvering around the docks I felt an immediate loss of control.

- This prop felt closer to the Stiletto in that trimming the motor up and down provided a large range of movement.

The Mirage and Vensura had less movement range.

posted 02-13-2013 06:14 PM ET (US)            

Vent holes can be helpful on some marginally powered boats that have four stroke power where there is not enough torque generated at lower RPM to satisfactorily accelerate a boat onto plane.

For a two stroke powered Whaler, there is almost no situation where propeller vent holes help *except* for a boat where there is a sudden and substantial added load at the same time you need fast acceleration. When pulling a water skier out of the hole, in others words.

posted 02-13-2013 06:34 PM ET (US)            

Jasper's 1998 Mercury 200 EFI is mounted "One Hole Up"

o
o <-- Bolts through this hole
o
o
o

This is the absolute lowest motor mounting position one would ever mount a single outboard on a 22 foot Whaler. It was the recommended mounting position back in the late 1970s when the hull was introduced and aluminum propellers were mostly all we had. This position will leave the A/V plate solidly buried at planing speeds.

Today that motor should be mounted two or three holes up, depending on the propeller used.

It helps with the testing of these four propellers because it allowed them to all be used at one motor mounting position. I guarantee you that the VenSura will begin to loose grip even if raised one more set of bolt holes. It cannot tolerate any mounting position where the blade tips break the surface. If it does, it just blows out. The VenSura is good on sterndrive powered boats where the drive *is* solidly buried.

posted 02-13-2013 06:39 PM ET (US)            

quote:

---

I've recently become a convert to 4 bladed props. Smoother (less vibration), great grip and midrange. Slight loss in top speed compared to a 3 blade.

---

posted 02-13-2013 06:59 PM ET (US)            

Stiletto Advantage -- 5500 RPM @ 46.7 MPH (12.3 % slip)
VenSura ----------- 5800 RPM @ 47.1 MPH (16.1 % slip)
MIRAGEplus ------- 5600 RPM @ 45.8 MPH (5.5 % slip)
Enertia ------------ 5700 RPM @ 47.5 MPH (13.9 % slip)

This shows that propeller slip is not an absolute gauge of anything; it depends on the model of propeller being used.

The MIRAGEplus has the lowest calculated slip. I would expect that because I typically see a range for this propeller of 5 to 8 percent, so 5.5 is right in there.

The Enertia has the next lowest at 13.9 percent. Again this is not surprising. I typically see 10 to 15 percent slip with the Enertia.

Likewise, the four blade VenSura, at 16.1 percent is in the normal range. I've seen slip between 10 and 18 percent with is model (a.k.a. Mercury Offshore, Quicksilver Typhoon). This also illustrates how general rule-of-thumbs like "a four blade prop grips better" are not always helpful. It depends on exactly what model of propeller you are talking about.

posted 02-13-2013 07:23 PM ET (US)            

I've never fiddled with the engine heights on my previous boats. My 19' Outrage had it's motors mounted with blind holes, I really wanted to raise those but did not want to pay for two sets of brackets.

I'm willing to have the motor raised on this one. I need to pay attention next outing to the AV plate when on plane. For some reason I felt as if it was mounted at a decent height just looking at the gap between the lip of the transom and motor mount (I know that doesn't necessarily indicate anything of value).

Looks like I only have one more hole to go up?

posted 02-13-2013 07:49 PM ET (US)            

http://s7.beta.photobucket.com/user/Triton_38/media/1993%20Outrage%2022/ 26b2d20b.jpg.html

The zincs threw off my perspective in the dark.

posted 02-13-2013 08:34 PM ET (US)            

quote:

---

PVS Vent Plugs: Don't bother testing propeller vent holes on your boat unless you have time and fuel to burn.

---

Tom--I got as far as buying three PVS vent plugs about seven years ago. I think it cost me $5 at that time. I have had them for seven years, and have never gotten around to trying them. I think that is because I don't have that much (boating) time to burn.

posted 02-16-2013 09:21 AM ET (US)            

As far as I can tell, I have complete and thorough understanding of PVS vents. I have read the Mercury literature. I have read many comments about PVS vents. The PVS vents behave as follows:

--they have no effect on low speed performance
--they have no effect on high speed performance
--they have effect only in a limited range of boat and engine speed

At low speed, PVS vents have no effect because there are no exhaust gases coming through the propeller hub. Please refer to my video that clearly shows this. There is no effect from PVS vents.

At high speed PVS vents have no effect because the exhaust gases are prevented from escaping through the vents by the Venturi effect of the high speed water flow around the hub. I have not recorded this on video, but this is what Mercury says will happen. There is no effect from PVS vents

At some intermediate speeds, where exhaust gases begin to flow but the boat speed has not increased enough to create the Venturi effect, exhaust gases will flow both through the main hub and through the vents. Again, I have not recorded this, but this is what Mercury says will happen. This causes an effect. The effect is to cause the propeller to spin in aerated water. A propeller spinning in aerated water is easier to turn than a propeller spinning in solid water. In the speed range where exhaust gases escape through the vents the propeller is easier to turn. It also produces less thrust. This must be true. Thrust is based on the mass of water accelerated. Since the aerated water is less dense than solid water, it creates less thrust. The effect of the PVS vents is to create less thrust during the boat speed range when exhaust gases escape from the vents.

The above is what I have experienced first hand. I describe it as the rubber-band effect, because the boat behaves like the propeller shaft is a rubber band. The engine spins rapidly, twisting the rubber band. The energy applied does not translate into thrust. Slowly, as the boat accelerates to a faster boat speed, the rubber band effect dissipates and the propeller begins to return to normal. The PVS vents are actually worse than a rubber band. With a rubber band you would store up some energy in the rubber band. With the PVS vents you just lose the thrust in the aerated water.

The whole purpose of PVS vents is to allow engines that cannot handle the full load of the propeller during certain engine speed ranges to temporarily shed the propeller load at those engine speed ranges. This allows the engine to accelerate to a higher engine speed, where the engine can produce more power. The PVS vents then begin to stop venting, returning the propeller load to full.

This is how PVS vents work. It is not necessary for me to explain anything about a particular boat-motor-propeller combination in order to explain how PVS vents work.

posted 02-16-2013 11:58 AM ET (US)            

The Stiletto Advantage, including the one tested by Jasper, have fixed 1/4" drilled vent holes that are no benefit to either Jasper's Outrage 22 or the typical Montauk.

posted 02-18-2013 09:55 AM ET (US)            

quote:

---

...opening up vent plugs on lower raked Mirage Plus props, which are mostly designed to be run fully submerged...is a waste of time.

---

In this comment, L H G seems to be implying that propellers, which are designed to be run at elevated heights with portions of their blades out of the water, may benefit from PVS vents. I think L H G may be correct, but further explanation is required. Allow me to explain.

If a particular propeller is marked with a pitch that is representative of the effective pitch that will be produced when the boat is operating at high speed with the propeller running at a mounting height so the blades are partially out of the water, the pitch marking for the propeller is likely to understate the actual pitch of the blades. The blades probably have greater actual pitch than indicated, but are marked lower in order to compensate for all the lost thrust from running in aerated water when on plane at high speed. At high-speed plane the stern of boat will be dramatically lifted. This is what raises the propeller out of the water.

On these same boats, when not on plane at high speed, the boat will sink much deeper in the water, particularly at the stern. This will immerse the propeller completely in the water. I have never seen a boat where the engine mounting height was so high that at displacement speed the propeller was operating with the upper blade tips out of the water.

For these very high speed boats which will experience a substantial hull lift from their transition to high speed planing from displacement mode, then use of PVS vents may be helpful. The PVS vents will spoil the thrust of the propeller while still fully submerged during acceleration when the boat is transitioning to plane, giving the same effect as a reduced pitch that will occur when the boat finally reaches it very high-speed plane with the propeller operating partially above the water.

This is a reasonable situation where PVS vents may be useful. But I don't find this situation is at all likely in operation of Boston Whaler boats. Generally Boston Whaler boats do not transition to plane from displacement mode with so much hull rise that the relationship of the propeller to the water surface changes so much that the propeller goes from operating completely submerged to operating with its upper blade tips above the water. The result is that the propeller, even on plane, continues to behave as if were fully submerged.

L H G also says:

quote:

---

The higher raked, most recent designs like the Trophy PLus, Enertia, Tempest Plus, Fury and Rev-4 are the ones that MAY benefit from the vents.

---

I have experience with using the REVOLUTION4 propeller that L H G mentions. My observation is that its marked pitch is lower than its actual pitch. This is based on using a REVOLUTION4 of the same pitch as several other propellers used in testing. The load of the REVOLUTION4 was much greater than the other propellers of the same marked pitch, as indicated by a very significant drop in engine speed at full throttle. The most reasonable inference from this observation is that the pitch of the REVOLUTION4 is marked lower than the actual pitch.

Based on the advice offered by L H G, it would seem that the REVOLUTION4 is probably one of the propellers intended to be run at a high mounting height so that when on-plane some of the propeller blade is no longer submerged.

Unfortunately, I don't think that the REVOLUTION4 is used that way in most applications on Boston Whaler boats, because in most applications a Boston Whaler boat never gets to a planing speed where the propeller is running above the surface.

posted 02-24-2013 01:34 AM ET (US)            

http://i7.photobucket.com/albums/y277/Triton_38/1993%20Outrage%2022/ DC477281-E49C-429D-B418-455E9A580227-2739-000003A50758543C_zps8bc9cd27. jpg

posted 02-24-2013 01:34 AM ET (US)            

http://i7.photobucket.com/albums/y277/Triton_38/1993%20Outrage%2022/ DC477281-E49C-429D-B418-455E9A580227-2739-000003A50758543C_zps8bc9cd27. jpg

posted 03-11-2013 09:58 PM ET (US)            

Larry, anything you suggest I ask the mechanic to look out for on the motor (in terms of servicing)? Last spring I had the typical lower unit oil change, plugs changed, thermostat changed, poppit valve changed, and everything greased/lubed.

posted 03-11-2013 11:23 PM ET (US)         

1. Head gasket deterioration with saltwater use. For an engine the age of yours, it's good preventive maintenance, and not expensive. I had mine done about 4 years ago just to be safe, and they did show a little corrosion deterioration, although probably would not have caused a problem for several more years. It's about $150/engine.
If yours are original, I would consider this maintenance.

2. Look for yoke and steering arm corrosion. With the engine trimmed partially up, grab the lower unit and see if there is up/down play. There should be none, but if there is movement, the yoke (bottom of the engine support on the transom bracket) may need replacement. I'm told that's an expensive job, about $1600, but if it fails underway, you can get the engine powerhead in your lap!

3. Make sure oil injection plastic hoses are in good shape.

posted 03-24-2013 07:13 PM ET (US)            

http://i7.photobucket.com/albums/y277/Triton_38/1993%20Outrage%2022/ DFDE50F3-6A5E-4F30-A7F5-C00370E7E900-1252-0000023DBE8A6896_zps8bc3c867. jpg

http://i7.photobucket.com/albums/y277/Triton_38/1993%20Outrage%2022/ 8E98130A-EE71-4798-B697-0ABA37DD8FEB-1252-0000023DC7E5A17C_zps5fd276d7. jpg

http://i7.photobucket.com/albums/y277/Triton_38/1993%20Outrage%2022/ CCC16E94-E827-4156-8638-76BEC5C3B172-1252-0000023DCDC0B09D_zpsf974bff4. jpg

http://i7.photobucket.com/albums/y277/Triton_38/1993%20Outrage%2022/ 1BA9C413-B322-41BB-9E71-0215680314DA-1252-0000023DD632A435_zps828f8b5d. jpg

Similar conditions to previous test, didn't get speed for each rpm but I did get a new max speed of 48.8 trimmed way up and against the wind. RPM's were slightly over red line at 5800-5900 so I didn't stay there for long.

I did seem to pick up about 200 rpm.

I was able to test in a number of different wave conditions and going in a straight line I did not have any problems cavitating even with the motor trimmed up.

I did experience cavitation when making sharp turns. Trimmed down, the turn was acceptable.

The speed I'm getting out of this prop is really impressive, 4000 rpm is giving me 34-35 mph. I'm used to knowing how fast I'm going by listening to the motor, but with this prop I keep under estimating my speed.