This may be it. There is a spring on the opposite side from where the spark plug goes in that helps control the speed of the engine. It could be bent, stretched, or loose. I got around some bushes with my HU775L and suddenly the engine speed went from full power to an idling speed. Finally figured out the spring got bent & stretched. Sort of fixed it with needle nosed pliers. Came here looking for a replacement spring and a GOOD diagram of the engine parts.
Still looking for that info.
Well, since it was such a simple fix and the mower is so powerful, I decided to keep it. I may put a cover to protect the innards this time, but meanwhile, the spring I put is not the exact one and it seems to be running the engine too quickly. Lars did you ever get ahold of the original spring or find a suitable replacement? I'll post back if I find one, as well.
Jon,
You can get in touch with our customer service representatives and give them the specific product number and they can find the OEM part for you. Just call 1-800-487-5951.
I hope this helps.