Most likely cause of high speed miss?

[dragginanchor]

Hi all,
My bayliner with the 2.3 OMC has developed a high RPM miss above 4500 RPM, but starts and idles great, gets on plane easily, and cruises at 3500 RPM smoothly. Can sometimes take it up to 5000 or 5400 with no miss, but eventually will start to miss. It's erratic, and prevents me from going full speed when I find a smooth stretch of lake :-( Checked plug wires - there all 10k Ohm or less even while bending/moving them. Checked Dist. Cap and points, they appear clean and like new. Checked one plug, it was clean and like new. Whats the next most likely cause ?

 

[Bondo]

Re: Most likely cause of high speed miss?

Whats the next most likely cause ?

Ayuh,... Lack of Fuel,... She's goin' Lean...

 

[dragginanchor]

Re: Most likely cause of high speed miss?

You were right Bond-o , but indirectly. It seems my 2 weeks of trouble were caused by bad fuel -first time I used cheap ethanol fuel. I think the ethanol absorbed water the two weeks it was hot and dewpoints 70-80+ here in MN. This leans out the air/fuel on a carbureted engine. Heck, just the ethanol does too. This caused unburned fuel to get into the engine oil and cause a valve lifter "ticking" sound.
Anyway, an oil, and filter change,(had gained 3/4 qt of oil-smelled like gas) and removing all the old gas from the tank, and 10 gal of good 92 non ox fixed all the problems..

Damn humidity, live and learn..happy boating