I had a free day on my last trip to Thailand and decided to help the guesthouse owner swap the motor in his Thai Longtail Boat. I noticed them working on the motor on the patio and offered to help. They were happy to put me to work.
The default motor used in the larger-sized Thai Longtail Boats is usually some variant of a 4-cylinder Isuzu diesel truck motor. These boats are typically used in the Andaman Sea and other Thai coastlines for tourist excursions. The owner was losing money every day his boat was out of commission, so we needed to get it done quickly. By the end of the day, I'd learned that apart from hoisting the motors to and from the boat, swapping a Thai Longtail Boat motor is relatively easy.