A Reader Asks: I use AMSOIL Interceptor 2-Stroke Oil in my snowmobile and I’m wondering if it can be used in our older Mercury outboard engine?
Answer: The short answer is no. AMSOIL Interceptor Synthetic 2-Stroke Oil is the best possible choice for your snowmobile, but it is not appropriate for your outboard engine. While both your boat and snowmobile have 2-cycle engines, it is easy for many to assume that any 2-stroke oil is cross-compatible. This is not the case as notably different 2-stroke oil chemistry is required for each application.
The water cooling, relatively low RPM and tame tuning of outboard engines means that combustion chamber temperatures of your outboard are drastically lower than the internal operating temps in your snowmobile engine.
Because of this difference, outboard engines require a two-stroke oil with the NMMA TC-W3 designation. TC-W3 oils have “ashless” detergents that keep the combustion chambers, exhaust ports and spark tips clean. Ashless oils are designed to prevent deposit build-up and spark plug fouling in the outboard engines.
Your snowmobile requires a “low-ash” two-stroke oil which is usually identified by the API TC specification. Low-ash detergents form a trace amount of ash deposit upon combustion that is promptly ushered out of the exhaust pipe. Low-ash detergents do an outstanding job of keeping the combustion chambers, variable exhaust power valves and spark plug tips clean in hot-running, high strung snowmobile engines.
Using a low-ash 2-stroke oil formula in your outboard would be inviting deposit build-up in your exhaust ports and potentially fouled plugs. Over time, this is a recipe for very poor performance.
Conversely, ashless 2-stroke oils for outboard engines are ill-equipped for the high-heat, high RPM existence of snowmobile engines. Ashless TC-W3 marine 2-stroke oils are optimum for outboard engines, but will form very troublesome deposits in snowmobile engines.
Here are some better AMSOIL 2-stroke options for your outboard engines.
HP Marine Synthetic 2-Stroke Oil- AMSOIL’s elite offering for NMMA TC-W3 applications. An appropriate product for the latest DFI outboards or older engines. Can be used in oil injection systems or as a premix.
AIO Injector Synthetic 2-Stroke Oil- AMSOIL’s entry level synthetic oil that is ideal for older outboards with oil injection or premix.
Saber Outboard Synthetic 2-Stroke Premix- An ashless 2-cycle oil for premix applications only.
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