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STEP #1 UNDERSTANDING THE TERMINOLOGY

First and foremost is getting a handle on the terminology that’s used to describe the different products. The listing below is not all inclusive but for the most commonly used terms; (Select blue hyperlinks below to read more)

Engine Rotation - No matter whether you choose a longblock, power-package or complete turnkey bobtail engine the rotation is critical factor to know. Rotation with marine engines is always viewed from behind the engine looking towards the flywheel. Standard rotation (left hand) means the flywheel is turning counter clockwise looking at it from the rear, or another way to think of it is that the harmonic balancer will turn clockwise when standing in front of the engine looking at it. Opposite rotation engines (right hand) were common years ago however not regularly produced today as the later variety of transmissions; Hurth & Velvet Drive both have negated the need for this as the gears can rotate either direction without issue. Read More...

Marine Engine Longblock - This is a great value based option for freeze damage or when you experience any general engine failure but you cannot afford or simply don't need a complete turnkey bobtail engine. This term generally refers to the cylinder block & heads as well as the required internals of the engine. The longblock being classified as a non-complete engine is therefore not regulated by the EPA as the new complete turnkey engines are and therefore forced to use a catalyst system. Generally marine engine longblocks do not include the intake manifold, engine circulating pump, or flywheel. Depending on the brand product the "tin ware" (oil pan, valve covers, timing chain cover) may or may not be included. Much like the flywheel, since the tin ware is not considered a "wear" item some manufacturers do not include this with their marine engine longblock products. NOTE: Please be aware that Marine "Shortblocks" are no longer available. The reason being that the cost difference between a longblock versus a shortblock was insignificant versus the exponentially higher warranty issues that resulted with shortblocks. The two primary reasons for this were that the shortblocks cannot be fully tested after manufacturing as they can with a longblock. The other reason being that re-installing existing cylinder heads that have valve seating issues always causes serious longevity issues when installing these on a new longblock. IMPORTANT: When replacing a longblock it should be noted that none of the manufacturers cover warranty for water ingestion related failures. Therefore if you are replacing a longblock due to freeze damage you need to either be 100% sure your exhaust system (Read More...) is not cracked or replace it. We also recommend replacing youur engine coupler (Read More...) whenever replacing the longblock. The coupler is a wear item that transfers the power from the engine to the sterndrive or transmission and can only be replaced while the engine is out of the boat. Read More on Longblock Products...

Power Package - This term refers to the growing market for partially completed engines. These range from new longblocks with the fuel and electrical system already installed to this level of content but also including the desired exhaust system. Like the longblock the Power Package being classified as a non-complete engine is therefore not regulated by the EPA as the new complete turnkey engines are and therefore forced to use a catalyst system.The real beauty with the power package is they work great for the customer that needs a replacement but most of their ancillary accessories are still in good shape and don't need to be replaced. The other application that the Power Packages work great for is when you have a 5.0L and want to go to a 5.7L, or you have a the older pre-1996 260 Hp 5.7L and want the 300 Hp 5.7L, or when you have a carbureted motor but want EFI. Read More...

Bobtail Marine Engine -   This term generally refers to a complete new “turnkey” engine as required to complete a "drop-in" replacement project when the existing engine and all of the accessories are not in good condition. Depending on the manufacturer of the product in question these products generally come complete with fuel, electrical, cooling, and exhaust systems as well as the engine mounts yielding it ready to drop right in when replacing a “used up” engine. Turnkey bobtail engines are classified as complete engines and as of 2010 are therefore regulated by the EPA and now forced to use a catalyst system (Read More). With the introduction of the EPA regulations in 2010 Mercruiser introduced their extremely successful CPO product line (Read More) for Bobtail Marine Engines and Sterndrives in effort to combat this issue. For the obvious benefit of working around the EPA issue, this CPO product line now makes up the vast majority of repowers being sold. When replacing a complete bobtail marine engine you will need to determine if the existing coupler can be used and if the existing sterndrive or transmission will couple directly to this. In many cases of the engine is more than 10 years old you will likely have to change out the engine harness connection plug as these have changed over the years. It is also common to have exhaust changes since the exhaust systems have changed from 3 inch to 4 inch. There are several different manufacturer options as well as even the option of changing from one to the other if it makes more economical sense.  Read More...

Complete Package - This term refers to the combination of a turnkey bobtail engine (new or CPO), and in the case of a Sterndrive Package it would include the Transom Assembly/Shield (sometimes also referred to as the Gimbal Assembly) along with the Sterndrive. Select this link to read more about Sterndrives versus Inboards. Select this link to read more about Inboard Drive Variations.

Sterndrive - This term refers to the drive system on Inboard/Outboard powered boats. These can utilize a single or dual propeller drive design.  Two manufacturers; Mercruiser & Volvo Penta make up about 99% of all the OEM sterndrive sales worldwide.

Transom Assembly – Also referred to as the gimbal assembly or transom shield in the case of Volvo Penta products this term refers to the connection point between the engine and sterndrive on Inboard/Outboard powered boats.

Transmission – Also referred to as the gearbox this is the drive system on inboard powered boats. These typically come in different gear ratios and also different output flange angle configurations as required by specific prop shaft angles.

Helpful Hint – Be aware that most early twin engine powered inboard boat models used the cast iron body velvet drive transmissions in combination with 1 standard rotation engine and 1 opposite rotating engine. There were very few options as to propshaft angles and therefore the engine had to be installed such that the crankshaft was also at the required prop shaft angle. In the early 1990’s the bi-directional ZF Hurth and Velevt Drive 5000 series aluminum body gears were introduced that in large part negated the need for opposite rotating engines. Therefore if you are looking to repower an older boat that was installed with the earlier setup described above this creates an issue. This stems from the fact that