Random plug fouls 2,4,6

[scrutcher]

I dont believe my tuner has fell off, i dont hear any banging around, I had lower unit off a few months ago to change water pump not sure if you can tell if its loose or not that way bit i looked up towards my motor and nothing moved around

[JOE54]

some dont rattle when they fall off found several that didnt have a sound when shaking engine

[aussiejake]

Exactly what Joe54 said is what mine was like.

Mine took 12 months and many wasted parts to eventually find the problem, it was cracked, hanging by 2 studs and was wedged against the mid section casing.

Yours may or may not have fallen off or be loose, but only takes a flashlight and a long screwdriver to test.......obviously once the leg is removed.

[scrutcher]

Mine usually foul at wot

[scrutcher]

Went out sat. to fish a tournament and immediatly the motor fouled #1 plug so now it just seems a random plug on either bank will foul maybe 5-10 minutes of idle time frim loading it up last time to unloading it this time. So guess its back to chasing a gremlin ti see what would cause random plug to foul, when one does foul it only euns about 4800 rpm, I wouldnt think a fuel pump issues would be random, would maybe a reed cause random plugs to do this

[lpugh]

fuel/air pressure test both running and key off leak down rates. also check belt and tensioner. 70 in lbs before reaching stop.
Must do tests!

[scrutcher]

fuel/air pressure test both running and key off leak down rates. also check belt and tensioner. 70 in lbs before reaching stop.
Must do tests!

This has been going on for a few years have had it at multiple shops and of course they cant go out every day and keep running the boat its just random that it happens. I cant do the "required" test every time this happens the plugs just seem like they carbon up and foul sometimes I can go oit for months no issue the sometimes every time i go out it will juat pick a random plug amd foul, sometimes 2 plugs foul at the same time

[lpugh]

thermostats stuck open.
excessive low rpm or idle time
wrong octane of fuel
Oil quality
internal fuel leak, diaphragm's, injector seals, injectors, pulse pump
Test results required to be of any useful help.

Unless you just want to throw a few thousand in parts at it..

[JOE54]

^^^^^^+1

[EuropeanAM]

^^^^^^^ +2