2008 200 HPDI

[stevenflanagan]

long time viewer, new member. I have a 2008 200 hpdi. I was having problems with #3 plug fouling. several shops looked at this and all fuel systems were checked and every filter changed with no fix. well eventually the motor blew up. i recently had a brand new power head put on and i told them of the issue they checked everything and said they see no issues. everything checks out great on the computers. well 1 hour of run time and the issue is back. no codes on the computer etc. just a fouled #3 plug. I have swapped coil packs to eliminate this and the problem remains with #3 plug. Im really leaning towards the injector not properly firing or the plug not properly firing. the spark plug is a black sooty like carbon. after reading on the web, im thinking possibly and ecu, injector driver or the pulsor coil. I believe this is a intermitten issue, because i can turn the motor off and sometimes it will clear up for a few miles.also, when the issue arrives, i notice my voltage dropping from 13.3 to roughly 12.8v if that helps any

entire fuel system has been checked and cleaned, all injectors have been tested by 2 separate companies. I strongly feel like this is an electrical issue, and im not sure what or where to check. any insight?

 

[ondarvr]

Check for spark on that plug when it's acting up, you can put an inline test light on it or a timing light.

 

[stevenflanagan]

you mean like check it while im going down the lake at roughly 40 or 50mph. just trying to figure out how that would be possible?

 

[ondarvr]

Put the inline tester on there and have someone else drive the boat, or a timing light will have enough wire to typically reach around the front of the motor. A cheap induction tach will do the same thing and may reach the drivers seat.

 

[stevenflanagan]

i wil try to get this tested. the issue seems to occur when im running between 4500 to 5k rpm so its a bit dangerous to stand back their while running beings its on a bass boat.

Wouldnt the black soot on the plug, mean more of a lean issues, like the fuel injector is not firing? i feel confident the injector itself is good.

 

[ondarvr]

Black and sooty is too much fuel and/or not firing.

 

[stevenflanagan]

thanks for the info. this leads me to believe this is either the injector is not properly functioning via the ecu or driver or the plug isnt firing properly in which im not sure what exactly drives that. ive been told could be faulty pulser.

I just tested to make sure my plugs are firing when i try to crank and they are definitely firing.

 

[99yam40]

find a shop that has a Yamaha master tech, before you loose another power head

they should have a test prop to load the motor with while still on the trailer.
keeps people from playing on the back of boat going at speed

 

[stevenflanagan]

Ok so I swapped injector drivers and drove boat for 40min until it started acting up. Same thing #3 plug. #1 plug doesn't look the greatest either. I put a test light in between the plug and all appears to be firing properly when the issue occurred.