The height of outboards in relationship with the bottom of the hull is very important. The higher or “drier” the motor is the faster the boat will go until it reaches the point of ventilation “pulling air into the propeller” which will instantly slow you down. Most motors will be set a little bit lower to take off best. The motor can be trimmed, meaning hydraulics will rotate the engine higher at an angle, this will speed you at higher speeds. This works unless the boat front starts to bounce or “porpose” then the motor trim will need to come back down a little bit. Idealy the motor will have a jacking plate that moves the engine straight up and down instead of on a pivot like the trim. The propeller is very important and has to match the motor and boat to obtain the best performance. A prop that limits the motor speed to max rpm at wide open throttle is ideal. Some people use different pitch props to gain acceleration or top speed. Two numbers describe prop pitch the first number tells the diameter of the prop and the second tells the pitch.
A compression test is a way of testing an engine’s condition without tearing the engine apart. A compression tester or tool is used to check the compression pressure. An engine compression test will let you know if there is excessive wear between the cylinder and piston. When the seal between the cylinder and piston rings wear out the engine’s compression will drop. This sealing failure will also cause the vehicle to use excessive oil and the car may start to smoke out of the exhaust. A four stroke engine, usually found in cars, will vary per car but should be around 170-200+ psi depending on the static compression ratio of the vehicle. With high performance cars having higher psi numbers with the exception of turbocharged cars having low psi numbers. Two stroke engines and small garden type engines will have considerably lower compression. Generally these engines will be around 80-140 psi. These are the steps to check your engine’s compression.
The ignition switch lock is not hard to replace. The switch first needs to be exposed by removing the colomn area covering it. Older cars use a clip or a pin that can be pressed, that will allow the switch module to slide out. Many newer cars use a clip and a pin to slide the switch out. Many times you will need to rotate the key to a certain position for the switch to slide out. The older switches use mechanical connections to transfer the voltage from the battery to the starter and the ignition coil. Newer ignition switches use a electronic switch called a proximity sensor. The prox. sensor sees an internal metal tab and will switch the 12 volts on. The switch allows the car engine to spin over, start, then stay running.
A water pump circulates water from the engine and through the radiator to keep the engine cool. Most cars need a water pump somewhere around 120,000+ miles. Some cars like Hondas have the pump by the timing belt and some are driven off of it. These type of cars should replace the water pump at the same time the timing belt is replaced. The water pump is easy to replace in comparison to the timing belt. If not replaced, the water pump tends to die soon after replacement of the new, tighter timing belt. Many newer front wheel drive cars have the water pump on the left side of the engine. The pump is driven off an accessory belt that will need to be removed first. The belt tensioner will first have to be loosened. Many times the alternator acts as the tensioning device.
The turbo has been around for almost as long as engines themselves. Yet turbos are not in the least outdated. The turbo works as an air compressor for the engine. At 14.5 psi the turbo has doubled the amount of air going into a normally aspirated engine. The more air you can put into an engine, the more power potential the engine has. The turbo has two sides to it, one that compresses the air and the side that the exhaust gases pass through. The exhaust must pass by a cone shaped “wheel” of blades to exit the engine. As it does this it spins the wheel very fast. The exhaust side is connected by a shaft that runs to the air inlet side. This shaft is lubricated by oil that passes between the two housings. As the exhaust side spins, it turns a similar looking “wheel” called the impeller on the intake side. This side of the turbo is called the compressor.
Small engines can be purchased for many self hobby types. Places like Northern Tool are great for small engines anywhere between one horsepower to 23 horsepower engines. These engines are purchased for many projects like water pumps, go carts, homemade generators, log splitters and various other projects. Pay attention to your project before purchasing an engine. Some projects require verticle shaft engines where others need horizontal shaft engines. The engine configuration generally will not interchange with the others. You will probably need accessories also to couple the engine to whatever drive system you use. Generally the same store, such as Northern Tools, will have sprockets, and drive shaft coupling parts to connect to whatever parts and components that need to be driven. If you plan to make a go cart briggs and stratton and tecumseh both have race cart series. It would make sense to use the same engine so that you have all the same aftermarket parts available to you. If you plan to build a generator make sure the engine has a good governing system to control the engine rpms. A generator engine should be run around 3600 rpms to keep the cycles at 60 hertz as regular ac power.
