www.iFourWinns.com

Hello All, once again I'm new to this forum so please give me any constructive critisim needed to get the advice I need and also to help anyone else I may be able to.

My '93 Sundowner 215 has the OMC 5.0 EFI that runs like a champ until I hit about 30mph and then it just decelerates. Sometimes it continues to decelerate until I decide to let off the gas, sometimes it just quickly sputters and re-accelerates. It doesn't make any weird noises except for one time where it sounded like it may have backfired.

I have taken the boat out about a dozen times this year and it has only done it the last 2 or 3 times. Again, it runs like a champ below 30mph.

So far I have:
Checked all fluids - was good
Cleaned flame arrester - was fairly clean anyways
Replaced fuel filter - some debris, no water
Ran through about 10 gallons of gas with Sea Foam
Plugs = 2 years old

Any questions? Comments? Advice?

Much appreciated,

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1993 Sundowner 215
OMC Cobra 5.0 EFI
South Hadley, MA
Connecticut River Rat for life

Fuel pump.

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1996 205 Sundowner DLX
5.0FL Volvo SX Cobra
Tow Veh: 2012 Nissan Frontier Pro-4X

Yes, it sounds like fuel starvation (since you said it looses power but is not rough).

Most likely is fuel pump. Lots of threads about fuel pump problems on this forum

Other possibilities include:
Anti-Siphon valve at fuel tank clogged
Clogged fuel filter (but you already changed it)
Leak in fuel line allowing air in (not likely without visible fuel leakage)
Clogged fuel tank vent (not likely unless it takes a few minutes to loose power)
Exhaust leak in engine compartment (causing oxygen starvation, not fuel starvation)
Timing problem... vacuum hose broken going to distributor?

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"Knot Easy" 2000 Horizon 240 Volvo 5.7GS /SX
tow: 2017 Honda PILOT EXL-AWD
prev. boats:
'87 Chaparral 198CXL 4.3 OMC Cobra
'69 Jetstar 16ft Ski Boat, 115hp Yamaha
'68 Aluminum Jon Boat, 3hp Sears
'64 Water Wings