496ho gremlins strike again
 

Hi all , went on my longest ride since i got the boat ,95mile round trip , every thing running great ,runnig at 3200rpm which was good for the conditions ,10 miles to go and starboard motor started to cut out jumping from 3200 down to 2000rpm and it got worse and worse, i let the boat idle for a few min and set off again ,running geat again for about 4or 5 min did it again ,it did this all the way back to ramp ,the last mile i just tried to see if i could run more than 3200 and it could. put scaner on no codes 100%power . only codes that come up are the codes from the 10 pin plug at the back of the motor not beeing used the last one beeing code 191 , i am sure it did it on the port motor once ,just the first time it started happening . 2001 496 ho 143 hours , all gauges read nor at the time, i was haveing a great time , think i smiled too soon, any help on where to start first would be great, regards paul

buy a fuel gage,,,and check fuel pressure running,,,,

Where do you put the fuel pressure gauge on the 496?

I see a brass 45º fitting on the back of the engine is that where we hook it up?

There is a fitting on the fuel rail ,looks like the dust cap on your tyres,

its next to the coolant tank,,,you have to take out two 1/2 in bolts and push it to the side to see the schrader valve,,,its ez

Correct. There is a schrader valve on the fuel rail. Easy to get to.

Thank you guys!!

definately check the fuel pressure, but Id suspect the IAC motor. If you have access to a merc scan tool or the Rhinda software you can test them. sometimes they can appear ok at idle, but cause other issues while running.

Thanks guys, i will check F/Pr . i do have a merc/scan tool but no codes came up .How do you do a check for iac with scan ?? . can any one tell me the best place to buy iac and boost pump ,even if they are not the prob cant hurt to have them as spares as they are bound to break sooner or later . Thanks again Paul from England

Ok i took the boat out , and had the fuel gauge hooked up ,i checked presure before i fired it up and it read 47-48 pounds ,took it for a test out at sea and it ran perfect for 40 minutes fuel presure stayed at 47- 48 psi , it would just not break down . not sure how acurate the gauge is as its on about 4or 5 psi befor i hooked it up it never goes back to zero , i will try the gauge on the other motor tomorow and see if it reads the same . i allso have another gauge i can take off the car and try that . but i recon the psi is about right 43psi if the gauge is starting at 4 psi ?? only ran the boat to about 4200rpm it just ran smooth as silk, got a feeling this one is going to give me grief . dont fell like takeing boat on any long Jobs , any one got any sugestions . thanks