I spent several days last week in Virginia at Norfolk Marine, filming outboard engine how-to videos with a Yamaha Marine Master Tech. The Yamaha Master Techs are cream of the crop mechanics, and there are only four or five dozen of them in the entire country. I’d hoped to learn a bit and I surely did – but the most surprising thing I discovered was that when it comes to outboard engine maintenance, in some ways, we’ve gone back to the future. Let me explain.
Remember when we used to pull the fuel line from a carburated two-stroke outboard, and run it out of gas at the end of every trip? All of the manufacturers recommended this, in order to keep the carb from gumming up. But as time went on, this practice was dropped from the maintenance regime. With modern four-strokes, a lot of guys said, this wasn’t necessary.
On a whim, I asked the Master Tech what the most common problem he saw was, these days. “Fouled up carburators,” he said, “from letting the engine sit for too long without running the fuel out.” Then, I asked him what he meant by ‘too long’. “A couple of weeks is all you get with today’s fuel,” he responded. “Three weeks should be considered long-term storage.”
Naturally, adding a good fuel stabilizer (as we discussed in Duck Boat Blues) helps. But even with the additives, if you’re not going to use your boat in the next week or two, run that gas right out of it. You may have flash-backs to days gone past and old two-stroke operation, but going back to the future is worth it – especially when it can save you from going back to the dealership for service.