I have been trying to cure my acceleration problem for 2 years and nothing I have done has had any effect.*It doesn't get any worse but it doesn't get any better either.*The problem is when I move the handle forward to accelerate from idle it wants to bog or stall unless I hit the choke and give it a shot of gas.* Then it takes off and runs fine.* Sometime it will take off and run OK the first time when I leave the launch ramp but after that initial takeoff it will revert back to its old ways on subsequent takeoffs. Then if I don't hit the choke on acceleration it will just die.* The motor is on a 1985 Grumman 5.0 which is a fairly heavy aluminum boat for its size. Once I get past the bogging and it takes off I have no problem getting up to 5000 RPM and 25-29mph*depending on how many lard bellies I have on board.
*My compression is between 120 and 130 on all 3 cylinders.*
*I have totally disassembled, cleaned and rebuilt the carbs twice, including pulling all the soft plugs, soaking in solvent, shoving wires thru all the orifices, examining under magnification etc.
*I removed the high speed jets (both times)*and made sure they were clean and even tried putting in slightly oversize ones.
*I have checked the synchonization of all 3 carbs. *
I bought a spark tester and I have a 7/16 bright blue spark on all 3 cylinders (I replaced all 3 coils anyway out of frustration since nothing else worked).
*I have replaced the VRO pump and all the hoses attached to it.*
*I have checked the timing at idle and fully advanced (using a method found on this forum).* When I checked the timing I made sure the pointer was set right on TDC using a depth mike to make sure the piston was all the way up. *
I am at wits end and ready sink this boat to create an artificial reef.* Judging from posts I have been reading on this forum for the past 2 years this seems to be a common problem with this motor. Is there anything else I should try?