Mercury 115 4- stroke stuck on 4800 rpm

[sea dollar]

Just bought a 24' North River hard top with twin Merc 115 EFI Saltwater 4-strokes. It came with 13x19 props but only turns 4800.Dealer recommened 13x17,still turned 4800,but lost top end speed. One tach was 200 rpm slow ,but the other was right on. It is an aluminum boat with 120 gal. fuel.Both props hole shot well.Could i get the rpm with ss props?

 

[jim dozier]

Re: Mercury 115 4- stroke stuck on 4800 rpm

You should be able to get these engines into their operating range (you need to find out exactly what that is, probably around 6000 rpm) with any PROPER aluminum or stainless steel prop. Sounds like you need to go to a lower pitch (the theoretical distance 1 prop rev will screw into the water).

 

[quantumleap]

Re: Mercury 115 4- stroke stuck on 4800 rpm

Something doesn't sound right here. The 17p should provide higher than 4800 rpm. If you went down in pitch and there was no change then theres something wrong with the tach, motors, or throttle.