Cruising speed/RPM's on AJ290 or SD290???

[Youngin19]

I have been trying to figure out where I should be cruising at on my 290 Amberjack. It is set up with inboards. I have been cruising at 4000 RPM's, anything less I seem to fall off plane. At 4000 RPM's I dont think it is running at its best fuel efficiency.

What is everyone cruising at? Speed and RPM's.

 

[papertrail]

i have the 290 AJ although i have sterndrives. I cruise about 3500. This seems to be good for me. 5.0 mercruiser BIII

 

[Redhook98]

I had the 5.0 with B-II's in mine. I cruised at 3350-3400 withno problems. A friend with the inboards cruised at 3800 for the same speed. He had to use lots of trim on the tabs to keep it on plane at that RPM. On occasion, he could get it as low as 3500 or so. He has the 6.0-litres in his.

 

[Groucho]

Single 8.1 with b111's. I cruise @ 3600. it falls off plane @ 3300

 

[Youngin19]

We are looking at 4000 RPM and 22 MPH. We took a trip over the Memorial Day weekend and I burned a lot more fuel than I thought I was going to at 400 RPM's but it wouldnt stay on plane without it. I figured I should be cruising somewhere around 3600 RPM's but its not happening.

Any other imput???

 

[Groucho]

@ 3,600 I'm @ 29-30 mph.

 

[skolbe]

I have a 320, with the same motors and transmissions and the boat likes to cruiser from 3600 to 3800 rpm's

 

[Great Escape]

I know we are talking different animals however I have 6.2 with supercharges and B3's, cruise at 3000 rpm/ 30mph full gas, water, gear and two adults. The boat will actually stay on plane at 24 mph with the same load without trim.

 

[barrowgv]

log on to Boat Test.com. they test run many types and have the Searay you have.

 

[magster65]

Yes... boattest has very accurate specs. Mine are almost exactly what they reported.
My 2 x 5.0's like 3500-3600 rpm @ 32-33 mph...

 

[b_arrington]

We are looking at 4000 RPM and 22 MPH. We took a trip over the Memorial Day weekend and I burned a lot more fuel than I thought I was going to at 400 RPM's but it wouldnt stay on plane without it. I figured I should be cruising somewhere around 3600 RPM's but its not happening.

Any other imput???

When was the last time you checked your bottom and running gear for fouling?

Drag from growth (esp. hard growth) on the bottom and props really adds up quickly and can hurt your performance.