Help Maintaining Speed on 290 SLX

[Wildcater]

I bought a 2005 290 SLX this summer with twin Merc 350's. I love the size and capacity of this boat and where we boat on Lake of the Ozarks, it allows us to run much farther down the lake where the waves can be 3 to 4 ft on a weekend. But what I've struggled with is being able to find a nice cruising speed and maintain it. For example - I get the boat up on plane, at throttle back to hold my speed at say, 25mph. But slowly it will lose that speed and drop off plane. So I throttle back up and try to do the same thing at 30mph. Once I back the throttle down a click or two, the boat either a) begins to slow again or b) continues to accelerate now that it is on plane. I have tried the trim tabs but that doesn't seem to work well. And trimming the engines up - I quickly get washout. Any 290 owners on here that can advise me?

 

[scoflaw]

Had the same issue with my 280 DA with twin 5.0's. Propped to high. Would have done better with less pitch and 4 blades at that.

 

[Wildcater]

It looks like installing an automatic trim tab system could eliminate the problem altogether along with some other benefits. Does anyone know if the factory trim tabs on a 2005 290 SLX are Hydraulic or Electric?

 

[Lazy Daze]

"Assuming" you still have the factory tabs, they would be Bennett hydraulic. Easy enough to figure it out by looking.

For your issue... I would experiment more before buying anything. Especially if this is your first real go-around with tabs. You have the drive and tabs "fighting" each other as you trim the drive up too high - especially at slow-medium speeds. Also, make sure the tabs are actually going all the way down. Tabs should make a very noticeable difference - if they are not, there's either a mechanical issue or possible operator error.

 

[scoflaw]

Hydraulic run by an electric pump. You could try that out manually first.

 

[Stee6043]

+1 to Lazy Days. You should not need auto tabs to solve this problem. You need to find the proper combination of tab, trim and throttle. More practice....or maybe find someone with a similar boat to show you how they do it?

 

[Woody]

+1 to Lazy Days. You should not need auto tabs to solve this problem. You need to find the proper combination of tab, trim and throttle. More practice....or maybe find someone with a similar boat to show you how they do it?

+1 This