3.7 4 cyclinder 170 mercruiser bogging please help

I have a 1986 sea ray sundancer 270 with twin 4 cyclinder mercruisers 3.7 liters.. i just bought the boat 2 weeks ago the seller said both motors where rebuilt ( not sure no papers ) and boat sat for about a year an half.. On the port side engine when i go to throttle up at times it will bogg then stall out and a few times when doing 6mph at 1500 rpm it stalled out.. but runs great once up to high rpm.. i replaced the cap, rotor, points, condencer, plugs, wires, fuel filters, acc pump and rebuilt carb and and put new gas in but im still having the problem.( having the problem whilein the water) timing seem to be on point at 8, now im not having the problem with the other engine which both use the same fuel tank. can anyone please help me on this? also i am new to this site and not sure if im in the right place..

Re: 3.7 4 cyclinder 170 mercruiser bogging please help

I have the same exact setup, and it sounds to me like it is a fuel issue. How much old fuel was in the tank when you topped it off? If the old fuel wasnt treated when it was put away you probably have some bad gas.

Re: 3.7 4 cyclinder 170 mercruiser bogging please help

Any luck finding the problem ?I have the same setup and since one engine runs to wide open with no issues and they are both drawing from the same tank I think it is something other than fuel.I just came doen from the cabin in pretty sloppy weather last night and had the issue only above 3000 rpms
below that there was no issue.