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Is My Outboard Engine Choking?

With the lid closed on my outboard motor well is it starving for air?   A question came in from one of our readers the other day about their outboard engine that is mounted in a well and is covered. The concern is whether or not the engine is getting g enough air to ensure proper combustion. Over the years this has been a concern on a lot of small boats that ran with outboard engines in a well. I owned one such boat myself about 20 years ago. The bottom line with that boat was that the only ...
Boat engine-cutoff lanyard in use.
Outboard engine David Gillespie

With the lid closed on my outboard motor well is it starving for air?

A question came in from one of our readers the other day about their outboard engine that is mounted in a well and is covered. The concern is whether or not the engine is getting g enough air to ensure proper combustion.

Over the years this has been a concern on a lot of small boats that ran with outboard engines in a well. I owned one such boat myself about 20 years ago.

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The bottom line with that boat was that the only way I could be sure the engine was getting enough air was to run with the cover open on the well area in the transom of the boat. The key to checking this is really easy. Run your boat at speed with the lid or cover in place and look for excess smoke exiting behind the boat. No smoke? That’s a good sign. Smoke could mean inadequate air getting to your engine. Also, make a mental note of the engine sound. Now lift the lid on the engine box. If the engine seems to perk up and smoke goes away, its a sure sign that the engine is not getting enough air with the box closed up.

I recommend adding a louvered air vent in the side of the box versus running with the lid off. Ready made louvered vents are available in a wide range of configurations at just about any marine supply outlet.

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