Minimum Cruising RPM for a Carver 3607 Aft Cabin (Lake Crawler)

[RGrew176]

I have found on my 3007 twin 270 Crusaders (350's) that about 1400 RPM gives me about 7 to 8 MPH and fuel burn is about as nominal as it gets with this boat. It varies by boat.

[Skydancer]

I appreciate ALL of the advice. Just the information I was looking for.

[Marcq]

This is an old tread but worth bumping up, I was wondering the same with my Santego, I don't want to go fast, I go fast enough on highways. But beside having to change the spark plug more often when running at low RPM, is there other things that could benefit running low RPM? At full RPM the boat takes a beating, when I bought my boat there was a lot of loose screws

Marc..

[km1125]

Lots of advantages to running a lower RPM. Less wear on the engine rings and bearings! Less heat overall on the engine, exhaust and transmission! You also don't have to run really low RPMs to get advantages. The engine might be rated for 4200 or 4400 RPM, but that doesn't mean you have to cruise there. We often cruise at around 3,000 RPM and it's a very comfortable ride. Sometimes we only cruise at 2,500 RPM but if the lake has a lot of chop it's nice if we bump it up a little and get on top of that.

You should not have to replace the plugs more often unless you're running so low you're basically idling it all the time. That's kind of hard but get over 1000 RPM and those plugs should be just fine unless you have some kind of fueling problem.

As an update to this thread, this past Sunday we had a bunch of kids on the boat and some didn't like to go fast. I was able to cruise easily at just over 9MPH (same boat - 83 3607 w/350HP Crusaders) and I could have done that all day and felt comfortable. You don't get much bow rise at all. Closer to 10 you'd notice that.