planing a 390 ec

eagleone

eagleone

Member
Aug 11, 2015
166
lake michigan
Boat Info
390 express cruiser 1985
Engines
2-454 mercruisers
Having trouble seeing over the bow when running at plane can not get bow down far enough. Tried both trim tabs down and up, can see some what over starboard side and nothing over the port side. Boat is new to me this August and got to know it yet. Any help out there in getting the bow down would be nice. thanks 1985 390 ec oh the trim tabs move but not sure they move the full 2.5 ".:smt101
 
I had the same issue with my 300, make sure the tabs are working. Then maybe do some weight shifting.
 
Eagleone, Go to the 390ec thread. One 390 owner developed an extra tab. I think Pietro? is the one i remember. Really not sure but that issue has been discussed. Good luck, JC
 
Does it flatten out any with additional speed? What speed/RPM's are you running? Is the bottom clean?

Is the water around you clear enough to you see your trim tabs from the dock to verify they're both working with their full range?
 
the boat is know foe being under tabbed

I added a second set of tabs between the tunnels
I plane quicker and go down a lot more now i can pull back on the trottles and stay on plane
 
The boats bow doesn't come down at any speed, the bottom was sand blasted and painted this summer. I saw that thread jc before but didn't remember the name, and was wondering if any one else is using the box or did what you did and add a nother tab.
 
I added a second set in between the tunnels. I hit a top speed of 28 mph this summer

Pietro made a fixed tab u can see on his tread.
 

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Something must be wrong with your existing tabs, additional tabs would make it better, however, there are 3 boats I know of out of Whitehall that all run fine with no additional tabs, maybe you have some extra weight from trapped water in the stern.
 
When the boat is at the dock you can actually see your tabs. Just verify that they are traveling down and you hear the pump running. Also try tabs full down than go to WOT

I added drop tabs to my new tabs and exsisting ones

Saverio
 
have checked the tabs for moving not sure it is the 2.5" but they do move. Haven't seen any water in the stern bilge is dry fuel was half full, water was almost full, and gray tank has about 2" in it. Still trying to find the thread with pietro post, I saw the box once I think will keep looking for it.
 
I would think the tabs would move a lot further than 2.5" measured at the end. I think every pair I have do. Are we talking about measuring piston travel or the amount the tip of the tab moves?
 
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