You can get add-ons that will either tell you the position or retract your tabs when the key is turned off. Both options are covered on Bennett's web site. http://www.bennetttrimtabs.com/

But without that, there is no way to tell. On my boat I just make it a habit to fully retract my tabs when I dock so the next time I go out I know exactly what position they are in.

 

There are pros and cons to a tab indicator. If your boating on a lake with no current and the exact same load on board at all times, they are great. Otherwise...nyah.

My boating is in varying winds and is tidal. Here's how I did it after I got my boat propped correctly. I'd start with the drive tucked all the way in and the tabs all the way down. I bring the boat on plane, bury the nose and raise the tabs until the RPM's went just beyond peak...that is the RPM's as I approach WOT curved from X to Y and started back down toward X. I would then bring the tabs down for a count of one thousand and one (~one second). I'd then trim the drive up until the boat started to porpoise and the prop started to cavitate. I trim the drive back in, again for a one second count and I am at optimum plane and fuel consumption.

I thought about a tab indicator but am afraid I would become to dependent on it as opposed to my gut and my ear.

Now I would change my view entirely if I had flowscans to match my gut to a measurable set of numbers.........Until then.....

 

Caymancanuck: I have a 270 SLX and, at first, had the same issue. Here's what I do:

Before I take off, I count to four while holding both buttons to lower both tabs. Then I raise the port tab for one count. That puts the tabs where I want them when the boat is normally loaded. If the mother-in-law is on the boat, then I have to fiddle with the tabs a little bit to get things even again.

To get an idea of how many "counts" it takes for your tabs to go all the way up or all the way down, have someone watch them while you raise and lower them all the while counting "one mississippi, two mississippi, three mississippi, etc."

If you have any issues that are directly related to a 270 SLX, let me know. I've had mine since August 2005.

 

Thanks 270SLX, I would be interested to know what your expereince has been with top end speed. I have been a little diappointed but I think that is due to some rough weather, new bottom paint and the fact the boat was not properly trimmed. Last weekend, on my own with 50% fuel, I was able to get it up to 44 on the GPS at just under 5000rpms. My props are a little dinged up and I will replace them in the spring as I am just getting over the new owner cash outflow. i am also in the process of replacing the Navman 5500 with the Northstar 550 with Smartcraft Gateway.

Nice to see another 270 SLX owner on the boards, I hope to post pics soon.

 

My 270 SLX performs identically at 44 mph on the GPS but only has the 320 horse 6.2. I would think you'd get 3 to 5 mph more w/ 425 HP.

You might consult Mercruiser. They might recommend a different pitch prop or might even swap yours to get the performance they think ideal.