Listed below are the questions (and their answers) that we are most frequently asked with regards to boat set-up and engine modifications. If you would like more information about our products and services, just give us a call. A technician will be glad to try and answer your questions - free of charge.

"Please do not write for technical assistance. It is impractical to provide detailed and personalized technical guidance by mail."

WHERE DO I BEGIN HOPPING UP MY RIG?

ALWAYS start by examining your basic combination first. For example: Is the hull style suitable for your intended use, speed range and water conditions? Ideally your hull choice will be one that makes the most of available horsepower. You can determine this quite easily by paying attention to what brand and model hulls win in racing classes similar to your combination or by watching what the local "hot dogs" prefer.

There is little sense in pouring hundreds of dollars into trying to hop up a "barge" (unless you have some financial interest in working with that particular brand)! Likewise, make the same examination of your power plant. Almost all late model brands are acceptable candidates for modification. However, if a step up from a 4 to a 6 cylinder would be reasonable on your hull, spending your money there first would be a good idea.

Once you have a suitable hull and engine combination look at the rigging ("set-up"). This means tight steering, rigid motor mounts, and a bottom that is true and sharp ("blueprinted"). It also requires a good wheel (usually this means a LOT of trial and error on an unknown combination). A hydraulic transom is almost a must to optimize the engine height for your hull and blade combination. As speed increases you might also need a nose cone (maybe with low water pick-ups), Torque Tab, and/or exhaust extension ring.

Mix this together with lots of testing to get the most out of all of the above! If, after improving efficiency, you still want more performance (and who doesn't?) work on the basics BEFORE doing major engine modifications. Basics include: louvers on the cowling, velocity stacks, exhaust relief, removing thermostats, optimizing timing (for premium fuel), plastic reeds, and careful on-water tuning.

Only after the above is done should you consider more involved modifications. Unless you must operate on 89 octane or lower fuel, the place to start is with higher compression heads. Raising the compression is about the only modification you will make that actually INCREASES MPG and power THROUGHOUT the rpm band. Keep in mind though, the limits imposed by fuel octane.

WILL MODIFYING MY ENGINE SHORTEN ITS LIFE?

Modifications that increase power output (as opposed to modifications which strengthen parts) normally reduce the service hours of the engine between overhauls or replacement. Fortunately, the resulting life for most properly modified outboards is still very long (unless extremely radical modifications are made).

WHAT'S THE BEST WAY TO GET MORE POWER FROM MY ENGINE? I use my boat for informal lake racing and occasional water skiing. Some of my friends say to just bolt on a few parts, while others are telling me I should tear the engine completely down to the crank. Could I just go with N2O injection or maybe fuel injection?

There is no single BEST way for everyone! "Bolt-on" equipment like louvers, stacks, heads, etc., will increase power if the proper combination is selected. Starting with a properly balanced and blueprinted short block will enhance the reliability and performance of any engine. So if you can afford it, DO IT! However, if a mild engine is being built, the "teardown" is not a necessity.

Whether to go with N20 injection is another matter entirely; it depends on the type of power you want. While it offers a big increase in power, for a small investment, that extra power is only available for short durations. An N20 system which offers a 70 hp increase will only provide a few seconds of "on-the-button" time. If that kind of "power-in-a-bottle" is acceptable, N2O may be for you. Avoid kits that use carb spacers -- they hurt normally aspirated performance. Any improperly designed N2O kits are just melted pistons waiting to happen. Also, remember that your competition may not count a defeat from someone "on gas!"

For serious mega-power (where available) a "big bore" conversion provides the broad range performance improvement that "lake racers" are looking for. Especially since this retains the low-end flexibility of a stock engine! Remember, "There is no substitute for cubic inches!"

See the next question for information on fuel injection.

WHAT WOULD BE THE MOST POWERFUL COMBINATION, MY STOCK V-6 WITH MODIFICATIONS, OR ONE OF THE FACTORY FUEL INJECTED ENGINES?

Fuel injection is definitely the way of the future, but not because of power increasing capabilities! The fact is, fuel injection itself does NOT add significant horsepower to the engine. The extra power associated with performance fuel-injected outboards comes from the use of higher airflow throttle valve and reed assemblies. The fuel injection allows these modifications to be incorporated without incurring the low rpm bog and throttle response problems that show up with equivalent airflow carburetion systems.

Fuel injection is the answer whenever you encounter throttle response, or fuel control problems that cannot be practically handled with carburetion. So, while the fuel injection is nice, either way you will probably want to bolt on things like heads, etc.

CAN I RUN MY MODIFIED ENGINE ON REGULAR GAS?

If you build the engine with its optimum theoretical compression (above 11.5 to 1 depending on the combustion chamber design) then the answer is no! Such compression ratios require over 95 pump ((R+M)/2) octane. 100-LL aviation fuel is recommended at such high compression ratios. However, you can run super unleaded with the medium compression ratios found in our larger chamber dual plug heads.

MY BOAT NOW HAS MORE HORSEPOWER THAN I CAN USE. WHAT CAN I DO TO IMPROVE ITS HANDLING?

Well on outboards, after installing dual steering and properly adjusting out steering cable backlash, the next step is to add rigid motor mounts to reduce the fish tailing that causes dangerous chine walking. Chine walk is the tendency for your boat to oscillate back and forth between its port and starboard chines.

Installing a dash controlled jack to raise the blades at high speed will help top end and greatly reduce chine walking because it preloads the steering system with blade torque.

A nose cone and torque tab can help reduce the steering torque the driver feels at high speeds that are due to the "paddle wheel" effect of surfacing, high rake wheels, and the angle at which the engine has to run through the water. These modifications also can prevent chine walking.

For stem drive applications the most effective modifications you can make are the Stern-Jack, nose cone, and dual steering. The Stem-Jack improves handling for the same reason a hydraulic jack plates helps an outboard motor -- it preloads out the steering cables' backlash so that at high speeds the drive won't "fishtail" and causes chine walking.

Other items of importance to driving control are a foot throttle and steering wheel trim buttons. They allow you to keep both hands on the steering wheel all the time, and react faster to changing conditions. You will always be able to drive faster and safer under any conditions with these two easy modifications!

HOW CAN LAND & SEA GET MORE HP OUT OF MY MOTOR THAN THE ORIGINAL MANUFACTURER COULD?

A production outboard does not represent the maximum power that the factory COULD get from an engine design! It represents a compromise power level based on production costs, manufacturing tolerances and suitability for varying "user" requirements. The techniques that we recommend to increase engine power are no secret to the original factory engineers! They are, however, either too expensive or too high rpm biased to be considered for general purpose motors. There is "no free lunch" when it comes to modifying an engine for more power!

I HAVE A 300 HP I/0 RUNNING 60 MPH AND I WOULD LIKE TO INCREASE THE TOP END WITHOUT LOSING RELIABILITY. WHAT CAN I DO?

You have two choices to increase your top end after you have found the best blade type for your boat. You can either increase the horsepower or, if your boat responds well to positive trim, add the Stern Jack to increase top end and acceleration efficiency.

The Stern-Jack sets the out-drive back 8 inches into cleaner water and, more importantly, raises the wheel vertically (when you trim out) while it also increases the effectiveness of that trimming. It normally reduces chine walking too. On many boats the Stern-Jack will increase your top speed by 5%-10%.

Since adding 10% more speed takes well over a 20% increase in horsepower you might need to add over 100 Hp to match the Stern-Jack's efficiency gains! Adding that kind of power is expensive and it will cut your reliability, drivability, and gas mileage. So, if it works on you model boat, start with the Stern-Jack. Then, if you still want to go faster after that, start adding horsepower. Since the boat will run faster at any throttle setting, you can won't need full power as often; this can really increase the life of a wild engine!

I WAS TOLD THAT THE "X-DIMENSION" HAS TO BE RAISED WHEN INSTALLING A STERN-JACK. IS THAT TRUE?

No, that applies to older "stand-off-boxes"! "Stand-off-boxes" did require costly "X-dimension" changes because their location between the negatively angled transom and the out drive caused the blades to be stuffed deeper into the water. But our patented Stern-Jack does NOT go between the transom and gimbal assembly, it goes AFTER the gimbal housing. Thus it provides extra length between the pivot point and blades, so the "X-dimension" is effectively lowered ONLY at negative trim angles while it is RAISED at positive angles! The change in height occurs just when you want it too! It's just like a hydraulic transom jack on an outboard, but one that works automatically as you trim the drive.

HOW MUCH DOES IT COST FOR AN ALL-OUT RACE-MODIFIED V-6?

That is rather like asking "how high is up?" Special heavy-duty parts, inspection processes, etc., GREATLY affect the final cost of an engine. If you give us some idea of what you would like to build, we can suggest the required heavy-duty parts and services that you SHOULD include. Then you can see if it fits your budget.

WHAT DOES BALANCING DO FOR MY ENGINE?

Stock engines have not been what we generally call "balanced." While they do have counterweights on the crankshaft, those counterweights are just compromises. For example, the small bore 150 and 175 hp V-6 engines use the same crankshaft counterweights as certain bigger bore (heavier piston) V-6's! Outboard engines are generally designed with counterweights that minimize crankshaft vibration in the port/starboard plane (at the extreme expense of the fore/aft direction). This is done to reduce perceived vibration at the steering wheel (so the average owner thinks it is smoother). However, balancing the crankshaft to minimize the average peak vibration loads in ALL directions will increase a high rpm race engine's reliability.

Note: Most factory counterweights are too LIGHT. In such cases, weight must be ADDED to the counterweights (and/or removed from the reciprocating parts) to actually balance the crank-train. This is an expensive process and one more reason that the factory does not supply the crankshafts balanced for performance applications.

WHAT IS THE BIG DEAL ABOUT IMPROVING AIR FLOW OF PARTS LIKE REEDS?

Engine power is directly related to the amount of oxygen/fuel mixture it can ingest and burn. The increase in airflow of a large carb or reed cage is what gives an engine more power. All our airflow figures are based on a standard reference vacuum (1.5 inches of mercury) to help you select the parts that will give you the most increase in power for the least investment of time and money.

IF I BUY THE BOLT-ON PARTS, CAN YOU JUST GIVE ME INSTRUCTIONS ON HOW TO PORT MY OWN ENGINE?

Yes, but we will caution you not to use 10,000 drag porting on a family ski rig or bass boat. Just because it takes about the same amount of work to do wild or mild porting there is a lot more to consider. Nothing can make or break your satisfaction with porting modifications like deciding "if a little is good,, a lot is better!

 Once you have some target guidelines, stick to the recommendations. We have spent countless hours on the dyno, flow bench, and water to develop optimum port time/area/flow specifications. During that time we have seen the shape and contour of a single port edge make or break a particular engine. Keep this in mind if you are determined to "invent" your own porting. It is very easy for overzealous grinding to turn your block into an anchor with a couple of millimeters ground off the wrong spot.

MY DEALER HAS A PROP-SHAFT DYNAMOMETER - CAN WE DESIGN OUR OWN PORTING WITH IT?

That depends. If your dealer has a hydraulic "dyno" then NO! These devices do not measure torque which is required to calculate horsepower (nor have the hydraulic dyno manufacturers claimed they would). They only measure pump pressure in a closed hydraulic system, which a mechanic compares with look-up charts and notes to compare with a go/no-go chart for other stock engines in the same power "range".

Since these units do not measure actual torque, you can not make horsepower comparisons between different RPM levels. Also, these systems are susceptible to variables such as the temperature and viscosity of the oil, the gear ratio of the engine, the test rpm, and the list goes on. Without adding a strain gauge or other torque transducer to these units, they are not suitable for performance modification evaluations.

On the other hand, with a torque transducer equipped dynamometer, your dealer can compare before and after horsepower readings even when they are at totally different RPMs. This allows evaluation of hop-up improvements (or errors). It still takes a lot of time to work out good modifications, so the shop must be conscientious.

WHAT'S THE DIFFERENCES BETWEEN PROP-SHAFT AND CRANKSHAFT HORSEPOWER? WHICH IS MORE ACCURATE?

Either method of measuring power is fine, as long as you do not mix the two. On a power head crankshaft dynamometer you don't have to worry about things like the style of gears affecting the results. Prop-shaft dynamometers are much more convenient and test the entire engine assembly. Also, comparisons between different models and brands can be made with far fewer changes.

At any rate, if you gain 10% at the crankshaft you will gain 10% at the wheel. If you need to evaluate exhaust changes, a prop-shaft dynamometer (with a torque transducer to actually measure shaft torque) is the way to go.

Actual power losses through the drive train are in the neighborhood of 5%-10% (this will vary slightly with the style of gearing used). This is NOT counting exhaust restriction losses (which can be eliminated by modifying the stock driveshaft housing). Backpressure from a non-relieved stock exhaust system will reduce a STOCK power head's output by 0%-5% and MUCH more on a radically ported power head.

WHY DO I NEED TO SPEND THE EXTRA MONEY ON A HYDRAULIC JACK WHEN I GET THE SAME TOP END FROM A MANUAL SET AT THE SAME HEIGHT?

Any time you preset the engine for improvements in top end you're making sacrifices in your boat's performance at all other speeds. When you jack the engine height up for best top end, you might not always be able to get on plane (because the blades can not get a good bite in the water).

The only way to maintain your boat's performance out of the hole and at cruising speeds is to adjust the engine height for varying conditions. This is impractical to do without adjusting it on the fly.

WHY DON'T YOU PUBLISH TORQUE CURVES FOR ENGINES INSTEAD OF JUST HORSEPOWER CURVES?

Are they some kind of secret? Actually, the torque information is right there. To get the torque of any engine (when you already know the horsepower at that RPM), multiply the Hp times 5,252 and then divide by the RPM! i.e.: Assuming an engine produces 150 Hp @ 4,000 RPM, it has 197 ft. lbs. of torque at that same RPM. (050 x 5,252)/4,000) = 197

WHAT IS BLOWOUT?

"Pro peller blowout" refers to a sudden loss of forward thrust caused by high-speed ventilation of the prop. It's as if the blades suddenly ran into a big air pocket in the water. The motor revs up, the boat falls off its angle of attack, and sometimes the sudden loss of steering wheel torque causes an unsuspecting driver to yank the boat into a left-hand hook. At very high speed, it can be startling and potentially dangerous.

The actual cause of the interruption of clean blade "bite" can vary. Some of the most common causes are:

1) Turbulence ahead of the blades from sources such as: speedometer pick-ups, depth transducers, and barnacles or imperfections along the boat's running surface or gear case. Fix these problems by relocating, removing or refinishing the offending item.

2) A damaged, poorly designed, incorrectly selected, or improperly modified blades. Repair or replace the blades. You won't always be able to tell if a blade is bad without inspecting it on a pitch block.

3) A gear case frontal design that has too high an aspect ratio to allow the water to flow along its surface at high speed without "de-laminating". The loss of laminar flow creates a vacuum pocket ahead of the blades. This is easily cured with a nose cone. It may also be given a "Band-Aid" cure with an exhaust extension or diffuser ring. The ring gives the water flow more distance to "re-attach" to the gear case surface before it reaches the exhaust (which otherwise will rush into the vacuum pocket).

4) A gear case that is "dragged" through the water at an angle (either trim angle or steering angle). This causes a vacuum pocket to build on the trailing side of the gear case. Changing the boat's balance, blade style, or engine mounting position can help reduce trim angle induced blowout problems. Crescent leading edge nose cones are designed to help in applications where trim angle must remain high. Torque tabs let the boat run straight without offsetting the drive angle, thereby helping reduce steering angle-related blowout problems.

HOW MANY MPH WILL A NOSE CONE INCREASE MY SPEED:

Since we introduced our original nose cone kit in 1973, dozens of shops have come and gone making exaggerated claims about nose cone speed increases. To set the record straight, the only time you are guaranteed to see large speed increases from a nose cone is when it prevents blowout.

For example, let's say a boat's top speed is limited by blowout to 85 MPH. If a nose cone prevents this blowout and allows the boat to run 91 MPH, some would say the nose cone reduced drag to add 6 MPH. This is not really the case. The extra 6 MPH potential was there, the cone just prevented the blowout so you could get to it.

Assuming a rig is NOT blowing out, a nose cone might still show speed improvement (or loss) from the bow or tail lift characteristics (depending on the installation) imparted by the cone. A nose cone with a low water pickup can also allow you to raise the engine and thereby decrease drag and increase speed.

In addition to the low water pickup, Land & Sea's nose cone exclusively has a built-in speedometer pitot tube which reduces the drag (and vulnerability) of standard pitot tubes. Figure about gaining 1 MPH from this alone on a fast boat!

HOW DO I SELECT THE CORRECT JET SIZE?

First, install jets that are large enough to insure that you are on the RICH side of the jetting vs. power curve (see graph). If the engine's jetting range is unfamiliar to you, it is best to start with jets large enough to cause the engine to "four-stroke" (indicated by very low power output, a flat "blubbering" high speed sound, and wet plug readings). If you do not know how to recognize these signs, remove the high-speed jets from the carbs and make a run, then you will have a feel for what four-stroking is.

Next, proceed to test each jet combination by bringing the boat up to top speed, for at least a full minute, and taking an accurate speed and RPM reading. Cut the engine off clean, and without any further running of the engine, inspect each plug insulator (and piston dome if necessary) for color. Assuming the plug color shows you are still rich, drop down ONE jet size and re-test, comparing the speed and rpm with the previous run. Continue dropping down ONE size at a time until the performance stops improving OR until plug (or piston) color shows a lean condition.

HINTS:

GOOD engine power will be found about one jet size smaller than the last jet size which four-stroked. MAXIMUM power will then be found a couple of sizes smaller still. Warning: See the next hint for more information on this. Crankcase charged two-stroke engines enjoy a slight increase in volumetric efficiency with a mildly over rich mixture (due to the fuel's latent heat of vaporization cooling the intake charge). They tend to have a flatter air/fuel ratio range over which good power may be expected (as compared to a four-stroke engine). So, if maximum fuel economy is not imperative, running the engine at the "rich" end of the safe jetting zone is a good way to get some extra insurance against thermal engine failure.

A charcoal or dark brown plug insulator color usually indicates that a smaller jet size can safely be tried. Once the plug insulator begins to show a light chocolate or tan color, further leaning can be risky. A light tan or white color indicates too lean a mixture (assuming that the plug is of the correct heat range, timing is correct, etc.) and must be immediately corrected by jumping to a jet several sizes larger!

DO NOT CUT CORNERS! Jets may seem expensive, and this procedure is time consuming, but the alternative is poor performance and/or MELTED pistons. Now that's expensive! You do not have to trim the boat out on the ragged edge to do this testing! In fact, for consistency it is best if you do the testing without even touching the trim setting between runs. For jetting, as well as evaluating other tuning changes, consistent test procedures with good INSTRUMENTATION are the key to success. Learn to do this testing accurately and you will find this "poor man's dynamometer" your best friend in getting peak performance. SAFE JETTING ZONE

You can save a great deal of time jetting by using a dynamometer. This will allow you to see the power curve change with each set of jets. It is much faster doing all of the sparkplug checks and jet changes on dry land.

WHAT IS BLUEPRINTING?

"BLUEPRINTING" is racer slang for bringing anything like the engine block, blades or bottom of the boat to specific dimensions. When mass-producing parts, manufacturers allow some deviation from the original design specifications or "blueprints." Racers re-machine parts to reduce these "errors," and that process is called "blueprinting."

i.e. When a stainless wheel is investment cast, a soft wax blade set (called a "plug") is made from a master mold. All deviations found in the original mold are transferred to each "plug." Further, while this wax plug sits waiting for the next step (ceramic coating), gravity will slowly sag its wax blades. The time between de-molding and ceramic coating (or how long coffee break was) can affect how different each blade on a finished wheel will be from the engineer's original design.

Depending on how far off a part's tolerances are (and in what direction), a performance gain is often realized when the deviation is reduced. At any rate, it makes for much easier tuning when every part is built to known specifications.

I STILL USE MY PERFORMANCE RIG FOR SKIING AND FAMILY CRUISING, WHAT CAN I DO TO IMPROVE OVERALL PERFORMANCE? I don't want to make motor modifications or turn it into a single purpose race boat.

Check out the very first question again. There are lots of items that actually ADD flexibility to a setup, and these are the things you should look at first.

A hydraulic transom jack or Stern-Jack lets you increase top end AND the ability to pull skiers!

Low water pickup nose cones allow you to run virtually any gear case height without fear of melt-down, and they improve handling.

HOW DO PLASTIC REEDS IMPROVE MY ENGINE'S PERFORMANCE?

That depends on what type of reeds you mean. The thick OEM single-stage fiberglass reeds actually represented a loss of horsepower and life expectancy over stock stainless steel reeds. Their only advantage was safety. Unlike steel reeds, if an engine ingests a plastic reed there will be little or no damage to the engine.

The performance of the single-stage reed improved as they were made with thinner with better materials to be more flexible and lighter than the steel reeds. The lower inertia of the lighter reeds needed allowed them to respond to the intake track pulsing quicker, so less charge was lost.

Further gains came about from the plastic reeds dampening ability, which makes them less susceptible to resonate frequency flutter. Still these gains over steel reeds were minor.

Then, Dual-Hinge™ reeds were introduced. These reeds do significantly increase the horsepower of an engine by promoting greater airflow, especially at higher RPMs. Recently, we started manufacturing our reeds in carbon fiber too. They are even thinner and lighter than the fiberglass reinforced plastic reeds. This latest generation of reed has the lowest inertia ever, and therefore are more responsive and less restrictive to intake flow.

Plastic reeds only significant shortcoming are that they do not last as long as the stock steel reeds.

I HAVE AN ENGINE WITH LOW HOURS. LAST SEASON I LOST THE #5 CYLINDER. - DO I HAVE TO BORE THE WHOLE ENGINE?

No, you do not need to oversize all the cylinders simply because you have to do one. Many people falsely believe that the engine will become so far out of balance (running with one oversized piston) that it will damage the engine and will intolerably rattle the boat. The fact is that the manufacturer's balancing specification are so loose that you will never tell the difference, it might even get better.

The fact is that the outboard engines are usually compromise balanced to reduce perceived shake in the port/starboard plane (at the expense of the fore/aft plane). The added weight of a typical .015" or .030" oversize piston probably falls within weight tolerances for the standard piston!

And as for the increase in displacement, the power of the one "big" cylinder versus the others is negligible. The change is just too small to worry about even in a performance engine.

For example, a Mercury 2.5 liter that has a bore of 3.5" and a stroke of 2.65" means that each cylinder has a displacement of 25.52 cubic inches. That means that a .015" oversized piston increases the displacement by only .22 cubic inches! At the most that piston might make 1/4 Hp more than the others!

In fact, boring the single cylinder is all that the OEMs provide warranty coverage for.  Keep the extra dough in your wallet!