Engine and Propulsion
The Exciter 135 was the only single-engine Yamaha jet boat ever built. It was powered by a purpose-built 2-stroke, 1131cc, triple-cylinder Yamaha marine engine that delivered 135hp at 6750 RPM.
This engine was the big-bore configuration of its 1051cc successor used in the 220, both of which were borrowed from Yamaha’s PWC division.
The axial-flow, single-stage, 155mm jet pump of the 135 was also derived from Yamaha’s PWC line.
It utilized a stainless-steel impeller, manual reverse, and innovative clean-out ports integrated into the rear platform. Thanks to their screw-in design, they were less prone to blowing out.
Yamaha used the same 155mm PWC jet pump across its entire 2-stroke jet boat line.
Features
The single-engine Exciter shared most of its features with its twin-engine brothers, including a ski hook, bilge pump, rear reboarding step, drain plug, 32-quart cooler, cleats, eyelets, navigation lights, grab handles, deck drains, and a pump clean-out port.
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Top Speed and Performance
Due to its single engine, the 135 was much less aggressive and playful than twin-engine models.
This is no surprise since the single-pump setup made the boat less maneuverable with fewer opportunities for tricks such as spins.
Yet, its engine power was more than enough to pull a skier or a wakeboarder, while its jet propulsion proved to be much safer than an exposed prop.
According to factory brochures, the claimed top speed of the Exciter 135 was 45 mph, which was 10 mph less than the 220.
In return, the 135 shined in terms of fuel economy and other owning costs.
The WOT fuel consumption of its single engine was only 14 gph and an estimated time of 2.4 hours.
(In contrast, the fuel consumption of the twin-engine Exciter 220 and 270 were 24.4 and 28 gph, respectively.)
If you just played around, its 34-gallon fuel tank lasted around two and a half hours if you were hard on the throttle.
Thanks to its patented hull design and small dimensions, the 135 was extremely maneuverable. It offered an amazing grip and was capable of quick sharp turns.
In tight corners, passengers appreciated the bolstered seats and well-positioned grab handles!
Problems
The main problem with the Exciter 135 was arguably its poor rough water performance.
While it offered a great boating experience on rivers and small lakes, it wasn’t recommended for larger bodies of water.
This is no surprise since its small hull with a low freeboard couldn’t handle bigger waves.
Another common problem with the 135 was the cavitation in its pump, especially in sharp right turns. Since its propulsion system was designed for jet skis, it didn’t fit in a boat hull perfectly.
This design flaw caused the jet pump to suck air instead of water at a certain point in the turns. Since the water couldn’t load the pump properly, it resulted in a cavitation impeller and finally a power loss.
This phenomenon was present on all early 2-stroke Yamaha jet boats, but it was way more prevalent on the single-engine 135.
Although it could not be eliminated, installing an aftermarket impeller could significantly reduce this negative effect.
Aside from this issue, it’s safe to say that the 135 was one of the most reliable Yamaha jetboats ever built.
Due to its single-engine configuration, it had much higher reliability and significantly lower owning costs than twin-engine models.