boat won't plane out

Peg_O_My_Heart

Coming back for some advice.  Our 310 2002 Rinker with MPI's and B3 outdrives won't get above 3000 rpms and plane out even at full throttle.  Tune ups have been done over the last two years and this last winer, the fuel injectors were cleaned on one engine.  Trim tabs work and are down, but boat won't pop out of the water.

I'm not a mechanic, but I feel there isn't much response in the throttles after they are 3/4 way open.  Boat is mostly empty and gas tanks only 1/2 full.

Anyone have ideas for what to look for?

raybo3

Maybe have a dirty bottom. Doesn't take long for marine growth to form and it will kill your performance. Even slim can cause problems. 

Ian

I have the 2003 version of the same and never use tabs to get on plane. Out of gear does it go over 3k? How do you start - slow increase or hammer down?

PickleRick

How deep can you dive into the OBD of the MPI?

If the bottom is clean I'd want to know if there are any codes, any stores codes in history.  Check all running parameters,  with twin engines compare one to the other.  

Then to basic things,  fire engines up after dark, look for arking around plug wires.  Check/change fuel filters.  Check spark at every plug wire. Test fuel pressure.   Check coloration on all the plugs.  Verify plug wire routing marches firing order.  Compression test if nothing else works.  

Pat310

I’m with Ian. My 310 doesn’t need tabs to get on plane. I know you said you had a tune up over the winter but i would also check cap and rotor along with @PickleRick ‘s suggestions 

aero3113

I would take a look at your cap and rotors again. Sometimes the contacts corrode pretty quickly.

YYZRC

Strange that both motors are behaving the exact same. I would lean toward something hull related. 

Aqua_Aura

How old is the fuel? As said previously if it is bothe engines than look at what they share. Hull bottom and fuel. 

Peg_O_My_Heart

I am going to get the boat pulled out and power washed to see if that helps