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OS FT 300 twin

Old 09-29-2014, 07:23 AM
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Default OS FT 300 twin

I have an older OS 300 twin which up until recently, started very easily tank after tank. Now, however, the engine still starts easily when cold, but, subsequently will not start hot. If it does start at all, only one cylinder will fire.

Any thoughts?

Thank you!.
Old 09-30-2014, 06:34 AM
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It sounds like the engine is losing compression when it gets warm. That could be due to a worn piston/ring/liner assembly or worn valves that expand a bit too much. If you can hear any air passing through the valves when you prop the engine when it's warm, then you have a bad valve fit. Otherwise, it's in the cylinder. If the engine runs well and still has a good idle and throttle-up, then you can choose to live with this new quirk. It's when the idle and transition start to go that you absolutely need to replace at least the ring and liner to get the engine running well again.

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