Canbt get RPM above 4000 on 1990 Indmar 351 engine

Just purchased 1990 mastercraf

Just purchased 1990 mastercraft Tri star 190 and can't get more than 4000 rpm and about 35 MPH out of the boat.Talked to previous owner they said it should rev to 4600 RPM and go 41 MPH. Tried replacing fuel filters still the same. Did test run on lake with engine cover off to look at carb secondaries and they fully open. Previous owner said boat was wooking great at end of last season now it won't rev out to max power. What could happen over the storage period? Thought the mechanical advance in the distributor could be the problem? The engine has holly 4 barrel carb. The carb was new middle of last season as well previous owner put electronic ignition in at that same time. Anyone have any ideas?

"The gas is older than last ye

"The gas is older than last year, there's no guarantee that they used any storage additives, the seller could have changed the prop, the advance springs could be bad/the weights could be sticking or the seller could have changed the prop. Gas loses octane when it sits for that long with or without additives and that can keep it from performing as well as it normally would. Do you trust the seller completely?

Go to www.tmcowners.com and do a search for Tristar or other Mastercraft topics. It's the Mastercraft owner's forum."

"old gas, might be gummed up c

"old gas, might be gummed up carb"