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View Full Version : What is The Mercathode on a 7.4 MPI



BloodShot
08-20-2002, 11:21 AM
I have a Solid Red 2000 Crownline 225BR with a 7.4 MPI, Bravo I outdrive and a 23P Mirage plus prop..My boat will only go about 54-55 mph@ 5200 rpm....Just wondering what the mercathode does, because some of the wires are not hooked up at all..The boat shit out on me this weekend...It was fine, then it started slowing down gradually until it was stopped....Now it will ony half ass start, hesitate, and pop....Just would like to know if it was fuel or ignition.....Also input on more top end would be nice....Thanks, Derek frown

BloodShot
08-20-2002, 11:25 AM
Also, all input will be rewarded with very nice pics of the previous weekend when the boat was running.... eek!

shockwaveharry
08-20-2002, 12:52 PM
There are sacrificial cathodes on your trim cyl's, prop shaft (behind the prop) and in the lower unit directly above the prop tip. They are designed to corrode over time instead of your boat parts. All four wires on the blue module should be hooked up. This system should have no effect on the way your engine runs though. Sounds like a plugged fuel filter would be the first thing to check, than go from there.

BloodShot
08-22-2002, 06:37 PM
Boat's Fixed, It was the fuel pump.. Well, at least it runs. Now, It is leaking something into the oil...I just drained about 15 quarts from the pan.. eek!

shockwaveharry
08-23-2002, 08:22 AM
http://www.dynamicdesignintl.com/images/dropjaw.gif
Think this guy has something to do with your bad luck?

SchellSchock
08-23-2002, 09:51 AM
If your fuel pump was pushing to hard and flooding the carb what is in the oil could be gas, flodding through intake past rings and into crankcase. Smell it, if it is gas it should smell like gas. MAke sure the new pump isn't causing the problem, refill with oil, start, run short time, and check oil again. If it isn't way thin and doesn't smell ya' shoulb be good to go.

BloodShot
08-23-2002, 11:21 AM
just cleaned the motor up and put fresh oil in it... It ran for about 15 minutes with full water going to it and the oil is still fine so far...Guess we'll see this afternoon at the water....
Shockwave, That imp is a pic of me when the bayliner was pulling me in!!!
I hid in the ski locker until we got to shore..
:D
Derek