On Engine Air Filters

"When I changed the air filter on my Beta Marine 1505 air filter recently, I recalled the claims of other manufacturers that their engines didn’t need an air filter for marine applications," writes Jay Bietz, who sails his Westsail 32 Pygmalion out of Alameda. "After seeing all the black stuff on my filter after only 155 engine hours, I’m glad the Beta Marine includes one on their engines. And thanks for the diesel maintenance article in the November issue!"

Jay’s instinct to change his filter after just 155 hours turned out to be a good one, because, as Tom List of Sausalito’s List Marine noted in January’s Letters, the denser the filter on your air intake, the more it needs to be cleaned or replaced. But the fine black residue on Jay’s filter wouldn’t be likely to damage a non-filtered engine.

"Diesels used in agriculture or in cars and trucks often are used on dusty roads, which can damage the inside of an engine," Tom explained to us. "Dust is very abrasive and will score the metal, but boats don’t normally have a lot of dust. Virtually nothing in the marine environment will damage a diesel engine, except water — even cat hair will go through just fine."

So while we’re glad Jay is thrilled with his engine — and that he’s taking such excellent care of it — we’re not worried that our Yanmar will kick the bucket any sooner for not having an air filter.

Marine engines — as with every piece of equipment we buy for our boats — are highly personal so you should choose the one you like the best, then maintain it regularly. If you do that, you’re going a long way toward ensuring your engine will run well for as long as you own the boat.