Safe Cruising RPM's

[Bdt 1967]

This weekend was the first time I drove my new (used) boat, it did great but going from an Evinrude high rpm 2 stroke to the Mercruiser 4 stroke 120, it felt real weird, I was used to running my Evenrude at around 4.5-5k pretty regularly for cruising and it had plenty of room to keep winding, but the Merc really seemed to be working hard at around 4k. My question is what is the safe cruising rpm for a Mercruiser Alpha 1 120?

 

[IVAZ]

Re: Safe Cruising RPM's

I dont think there is a magic number. Different hulls will require different rpm's. You need to figure out at what rpm's it planes.

 

[Bdt 1967]

Re: Safe Cruising RPM's

Very low, its just a little 16 foot Glastron Carlson.

 

[Bondo]

Re: Safe Cruising RPM's

but the Merc really seemed to be working hard at around 4k.

Ayuh,.... Probably because the recommended WOT is about 4200/ 4600rpms....

Cruising is usually in the 3200/ 3500rpm range for most hulls....

 

[Bdt 1967]

Re: Safe Cruising RPM's

Perfect Thanks for your help!

 

[Mkos1980]

Re: Safe Cruising RPM's

Ditto to the above. For me I'm doing 40 mph'ish around 3,000 and when I really taking it easy I usually go about 2200-2300 Rpms.