1800 SR Cruising Speed, WOT, and GPH Questions

[prosunseeker]

Hello Guys,

New owner here of a 1992 1800 SR. I acquired the boat from a mechanic and it runs like a top. I've never boated too much so I'm very green and I'm afraid of making costly mistakes. What is the cruising speed of my boat, max speed, cruise rpm, and max rpms? I've taken the boat out and it "feels" fine to cruise at 30 MPH for 5-10 minute squirts at 4,000 rpm. Am I damaging it? This is with 2 people on board, little wind, and flat lake water. I do not know what kind of prop I have.

Also, how long can someone go at WOT? Seems like mine tops out at 35mph with only me on board and at 4400 RPM the engine sounds like its reaching the end. Can boat engines sustain above 3500 rpm for long periods like over 20mins?

[mmwjr]

What engine do you have?

Running at WOT should not be used as a cruising practice. Running at 3500 rpm is with-in cruising range and I run my boat there for hours at a time.

[prosunseeker]

Originally Posted by mmwjr

What engine do you have?

Running at WOT should not be used as a cruising practice. Running at 3500 rpm is with-in cruising range and I run my boat there for hours at a time.

I have a 3.0L mercruiser.

[brian0128]

Originally Posted by prosunseeker

I have a 3.0L mercruiser.

Because of the variable design of different boats and how much weight is in it, the top speed will vary. All that matters is that your engine is operating in the correct RPM range at WOT.

If you have the 3.0, it has a factory recommended WOT RPM of 4400-4800. The best cruising speed would be about 3000-3500rpm after you were on plane for that motor.

[mmwjr]

+1 what brian said, seems like you are dialed in pretty close.

[cuzins101]

Originally Posted by brian0128

Because of the variable design of different boats and how much weight is in it, the top speed will vary. All that matters is that your engine is operating in the correct RPM range at WOT.

If you have the 3.0, it has a factory recommended WOT RPM of 4400-4800. The best cruising speed would be about 3000-3500rpm after you were on plane for that motor.

Brian - Do you have a resource to recommend for specs like these?

[brian0128]

I got the WOT rmp from the Mercruiser 3.0 manual and the cruising speed rpm is what is recommended for the 3.0 from an articlie in boating magazine.

[cuzins101]

thanks!

[shrew]

With a Max RPM range of 4400 - 4800, you should be able to cruise that boat at 4000 all day long, conditions permitting of course.

[brian0128]

Shrew is right that the motor could handle the higher rpm. The reasons the magazine stated that rpm for cruising was for the best fuel milage at speed. I cruise in my boat up to 4000rpm when I'm in a hurry.

[deanries]

prosunseeker -

I have been the owner of a 1992 1800SR with the 3.0L Mercruiser since 4/15/92. The information given for WOT and cruise speeds is legit. The WOT on my boat has been in the 4400-4500 rpm range. If you bend a blade or more, 3 blade 19 pitch prop on mine you will notice the change. I usually cruise in the 4000-4200 rpm range which gives me about 30-32 mph (depends on boat load). Max speed with just me on a flat water river was 38-39 mph but that was going with the current (light though). I am just short of 1300 hrs with my 1800SR and love it a lot, best money I have ever spent. Take a look at my album which is public. I think you will like what I have done?
deanries (Go Big or Go Home)