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Until a week ago my engine was running very well - idle ~700, a little rich but I was happy with that. I changed my plugs, which I last did in 2015, switching back from Autolite to Champion (due to availability). They are gapped to 38 and I have points.
After I switched the plugs the engine idled around 1,200 rpm. I decided to adjust the idle mix and the set screw, and the engine would bog down and stall out ~900rpm.
Here's what's weird though - WOT in gear is now > 2,900 RPM (tied to the dock). I chickened out before hitting the stops but it felt as though it would have comfortably gone over 3k, which I've never gotten even close to before.
I have a clean prop (Lake Ontario, and splash was late April) but before now I'd top out at ~2,600 RPM on a really good day early season before the prop got dirty.
I didn't change anything apart from the plugs, and to my ear the engine sounds like it's at low idle when the tach shows ~1,100, and 3K really baffles me.
I have no reservations about taking the carb apart and checking it's clean, but before I do, is there even a small chance that the tach is randomly high? The only thing that points me that direction is the really high RPM at ~WOT.
Prop is a 12*X (I think 9).
Everything else is great, 40-60PSI oil pressure, temperatures after 45 minutes running were 130-140, a little smoke but nothing untoward.
After I switched the plugs the engine idled around 1,200 rpm. I decided to adjust the idle mix and the set screw, and the engine would bog down and stall out ~900rpm.
Here's what's weird though - WOT in gear is now > 2,900 RPM (tied to the dock). I chickened out before hitting the stops but it felt as though it would have comfortably gone over 3k, which I've never gotten even close to before.
I have a clean prop (Lake Ontario, and splash was late April) but before now I'd top out at ~2,600 RPM on a really good day early season before the prop got dirty.
I didn't change anything apart from the plugs, and to my ear the engine sounds like it's at low idle when the tach shows ~1,100, and 3K really baffles me.
I have no reservations about taking the carb apart and checking it's clean, but before I do, is there even a small chance that the tach is randomly high? The only thing that points me that direction is the really high RPM at ~WOT.
Prop is a 12*X (I think 9).
Everything else is great, 40-60PSI oil pressure, temperatures after 45 minutes running were 130-140, a little smoke but nothing untoward.
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