350 MERCRUISER CUTTING OFF AT HIGH RPMs
 

Hello all -

I have been battling an issue over the past 2 months and the boat has been in and out of the shop twice at Sea Ray of Greenville (Hall marine) in Greenville, SC. My boat runs great at low RPMs and cruising speeds around 3k RPM. When I decide to hammer down on the throttle and run wide open at 4500 RPMs the engine will cut off, sometimes it will not shut off completely and sometimes it will not. First time in the shop they replaced the part where the plug wires hook up to. Its a long piece about 10-12 inches and has a "rotor" that spins on it. ($600 part). They also replaced the plugs and wires at the same time and my total bill was around $970 after parts and labor. That did not fix the problem!! So they do some more tests and called me and said it was my fuel pump. So they replaced that at no expense to me and now it is STILL doing it! It is EFI so I am guessing now it has to be something electronic maybe?? ... Anybody else experience this problem? its a 96 Z220 Talari.

Re: 350 MERCRUISER CUTTING OFF AT HIGH RPMs
 

I dont know if you are still experiencing this issue but you might want to check your knock sensors. Should have one on each side of the block. Make sure they are connected and if they are you can pull them off fairly easily and test them.
I put a new set of exhaust manifolds on my 7.4mpi and in doing so I broke a connector off of my starboard knock sensor.

Re: 350 MERCRUISER CUTTING OFF AT HIGH RPMs
 

Check your fuel vent. High fuel draw could be causing a vacum in the fuel tank if the the vent is plugged or not functioning properly.