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Noel Schembri
Noel Schembri, Marine Technician
Category: Boat
Satisfied Customers: 1954
Experience:  Advanced technical diploma
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I have a mercruiser 5.7 EFI 260 HP I/0 am wondering how

Customer Question

Hi I have a mercruiser 5.7 EFI 260 HP I/0 am wondering how high I can run the RPM's without damaging the engine.. and also what is the very best oil for this engine... thanks. James
Submitted: 2 years ago.
Category: Boat
Expert:  Noel Schembri replied 2 years ago.
Hello James, my name is ***** ***** I will assist you. Mercruiser recommends 4800 as maximum RPM for this engine and the rev limiter goes on at those RPM. thus you would not be able to run the engine at higher Rpm. To do so you would need to bypass the rev limiter which is not an easy job to do as it is programmed on the ECU. If the rev limiter permits though, the engine could be run a couple of hundred rps more but you would be risking. These engines are not made from stock to go at much higher rpm as to do so you would need to replace and modify some engine parts such as the crankshaft pistons etc... Normally the rule of thumb in marine is that if you need more power you go for a bigger stock engine and not upgrade the current engines. As for the oil, the best oil is fully synthetic SAE40 for high temperatures and SAE 30 for lower temperatures. If you need further assistance let me know. Noel
Customer: replied 2 years ago.
Thanks.. It does have enough power. Plenty. Planes out in seconds peaks at 4800 but did not hear the rev limiter yet a friend told me I shouldn't run it over 3800 or 4 so just making sure. Thanks again..
Expert:  Noel Schembri replied 2 years ago.
Ok no problem, If you need more assistance feel free to ask and kindly rate my service. Thanks,Noel