2.4L mercury Nightmare. Assistance needed

I'm Back Gentlemen,

I have had problems with this lemon of a motor since I bought it. It was a 2.5L 200 mercury that someone rebuilt and put a 2.4 powerhead on and switched over to EFI. Here are my problems as well as the test and parts I have already put into this. First, the motor would never turn over 4300 RPM's and would kill the motor after 10 minutes because of the stator overheating and shutting down. Neither the volt reg or stator were charging the batter. Stator and volt reg tested bad according to specs so Replaced both volt reg and stator. Fixed that problem So now the battery charges but the boat is still EXTREMELY rough out of the hole and not running good at WOT. Almost seems if it is bogging down. Once up to WOT it only gets 4500 RPMS max and is missing slightly. Took it to a mechanic and he adjusted the throttle and told me the 25P prop was incorrect for this 2.4L merc and I needed a 23p. So traded in for a 23P Tempest plus and it is still not running right. Could I have a problem with my switchboxes since it lacks power? Motor always fires right up and idles like a champ. Have 120 compression accross the board with spark on all cylinders. Any assistance with this would be helpfull as well as keep my wife off my back about this boat.

Re: 2.4L mercury Nightmare. Assistance needed

Yes, you could have a problem with switch boxes or the stator or the coils but you won't know until you do DVA tests. Find a better mechanic or get a DVA adapter and an analog meter and follow the CDI guidelines for testing.


Your mechanic pulled a dumbass move telling you to go from a 25 pitch to a 23 pitch. What did he think that was going to accomplish? A good running 200 HP 2.4 or 2.5 should be able to spin up to a 27 pitch prop with a light hull no problem. Plenty of bass boats out there turning 25 pitch props behind 200 HP Mercs.

No one ever follows my advice but here it is. Do yourself a favor. Sell the injection crap and buy yourself a set of 200 HP carburetors and a carb front end . You'll come out bucks ahead and your life will be much less complicated. A good running injection system runs like a dream. A bad running system is your worst nightmare. There is no huge advantage to a Mercury EFI over carbs anyway. Both get about the same mileage and make the same power. The EFI starts easier.

Re: 2.4L mercury Nightmare. Assistance needed

Thats what I was afraid of on the prop. Now I'm out on a prop and still have a bad running motor. Sometimes its worth taking it to a dealer and having it checked out professionally. I'm going to check the switch boxes tonight since I highly doubt its the stator. The stator and volt reg are brand new. Coils checked out good. So all thats left really is the switch boxes, injectors, reeds, and the part Im not looking to get into, the powerhead.

Re: 2.4L mercury Nightmare. Assistance needed

Youve stated you had spark . You could be losing it on the top end though. Your compression is fine for a fishing motor. Reeds almost never go bad and really only make engines run bad at lower RPM when they do go bad. Injectors do get dirty though and can make your life miserable. Tony Brucato can make yours run as good as new at a minimal cost . Brucato High Performance Products and Service. Brucato SVS (air intake system) and PCU (adjustable ECU) for Mercury EFI Outboards.