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Starboard Engine Misfiring

v4tuna

Well-Known Member
Messages
3
Reaction score
1
Points
60
Boat Make
Yamaha
Year
2005
Boat Model
AR
Boat Length
23
So my one engine started misfiring would not rev past 7000 rpm. would bog then stall. It would restart but idling like a tractor. Sometimes the power would come back like an electrical short or something as it revd it would smooth out . Back on lift remove and check plugs ....I didnt have new plugs but leftovers from 3 years ago last time I changed . I had to through 4 of those old plugs till i got 4 that worked. It purred for a few minutes Great. turn off motor. Go get fishing gear to go out come back. to poor start rough idle again. I have just bought new plugs for it but suspect maybe ECU is fouling plugs . Am I missing anything If I remove ECU has anyone tried baking in the oven to dry it out before sending for repair I thinking water can cause a short to ground.
 

v4tuna

Well-Known Member
Messages
3
Reaction score
1
Points
60
Boat Make
Yamaha
Year
2005
Boat Model
AR
Boat Length
23
Its a 2005. would fresh plugs run fine for a bit with a bad ecu till plugs foul
 

JetboatBrad

Jet Boat Lover
Messages
111
Reaction score
18
Points
77
Boat Make
Yamaha
Year
2018
Boat Model
242 Limited S E-Series
Boat Length
24
How quickly are they fouling out? And are they wet and gummy? I’ve never had an ecu problem so I’m probably not the best. I would think if you swapped ecu’s, put some fresh plugs in it and ran it. It should by process of elimination, tell you what’s going on. If it’s a bad ecu, your other engine will have same problems
 

v4tuna

Well-Known Member
Messages
3
Reaction score
1
Points
60
Boat Make
Yamaha
Year
2005
Boat Model
AR
Boat Length
23
Spark plugs fixed the problem .
 
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