Two-stroke troubles

Two-stroke engines require oil to be mixed with gasoline to keep the engine lubricated. Forget that critical step and you’ll end up with an expensive anchor. Photo courtesy

December 2023

By Randy Randall

Dad’s first real powerboat was a Corson. The boat was made of fiberglass, 15-feet-long, with a windshield and steering wheel and an 18-hp, two-stroke Evinrude outboard. In those days all outboards were two-stroke. Four-stroke motors were just coming in, but they were rare. We used the boat a lot, launching it at the local ramp and chasing mackerel all over Saco Bay.

One day I asked Dad if my friends and I could take the boat out by ourselves. To my surprise, he said yes. Maybe he was convinced that I’d been aboard the boat enough to know how to operate it properly. Maybe he was confident that I knew the Saco River and Saco Bay well enough. Maybe he just thought we all have to grow up sometime. Anyway, he said “yes.” We boys practiced being responsible by carefully backing up the trailer, launching the boat and parking the truck. We even stopped at the local marina and filled the tanks with gas.

I don’t remember all the details of the day, but I imagine it was a beautiful one in which we caught mackerel and stripers. On the way back, however, the motor died. We had no idea what was wrong. It had run so well all day. Somehow, by playing with the choke and squeezing the bulb we made it back to the ramp and hauled the ailing boat home. Well, as you have probably guessed by now, when we filled up with gas, we forgot to mix in the oil. In our enthusiasm for the day ahead, it completely slipped our minds. The fuel mix that was already in the tank, when combined with the straight gas we added, must have been enough to keep us going for a while . . . until the motor eventually overheated. The cylinder head warped and caused an expensive repair for my dad. Simple mistake for sure, but we all didn’t feel quite so adult when Dad told us the bad news.

That was the first time I ran a two-stroke engine without oil, but not the last. In the ’60s and ’70s most small engines were two-stroke. Beyond outboards everything from lawnmowers, to chainsaws, to snowmobiles ran on a mix of oil and gas. If we didn’t know the correct mix of gas and oil we defaulted to 50:1 and the engine usually ran. We even had a Saab 96 car that had a two-stroke engine. You poured a can of 30-weight oil into the tank every time you filled up. One innovation for two-stroke outboards was the invention of the oil-injection systems. These motors had separate tanks you filled with oil and a pump metered out the correct amount to mix with the gas and lubricate the engine. Something like that would have saved my butt more than once.

The years went by and while living in Bangor I had a friend who had a sailboat in Bucks Harbor. It was early fall, and he needed to bring the boat up to Hampden to have it hauled out for the winter. He asked me to go along, and so we drove the long miles to Bucks. His Catalina 22 had a 5-hp outboard mounted on a bracket hanging off the transom. We sailed out and around Cape Rosier, past Castine and into the mouth of the Penobscot. We skirted Verona Island and noticed the fuel was getting low. He had been running the little outboard for quite a while as the wind was on the nose and the boat needed help making headway against the river current. In the town of Bucksport we decided to stop for fuel. We found a dock and tied up and carried the three-gallon tank with us as we searched for a gas station. That went well, and soon we were back on the river heading for Bangor. Right away, and contrary to the way it had been performing earlier, the motor began to falter and stumble. We worked frantically to keep it going and bit by bit gained on the Hampden marina. A few days later my friend called and said the outboard was toast. We’d forgotten the oil. Once again, I’d slipped up and tried to run a two-stroke motor on raw gas.

The old two-strokes are getting harder to find these days. If you visit Grant’s Kennebago Camps on Kennebago Pond, in Western Maine, you’ll find 30-or-so old Johnson outboards chugging along because the guests there like things the way they were.

When we have a new employee at the marina, I quiz him on what he knows about two-stroke vs. four-stroke motors. But it’s always a one-sided conversation. I think these days we have two gallons of two-stroke oil for sale in the marina office. When that’s gone, I doubt we will be stocking any more.

Frequent contributor, correspondent and friend, Randy Randall is co-owner of Marston’s Marina in Saco, Maine and a dreamer and waterman of the first order. Just don’t loan him your two-stroke outboard.