2 Plugs Clean and 2 Fouled?

[Zara Spook]

2004 F150 with about 280 hours on it is being serviced right now, and the plugs in the top two cylinders were clean, while the plug in cylinder three was a good bit fouled, and the plug in cylinder four was heavily fouled.

Any idea what could be causing that kind of scenario?

[rodbolt17]

incorrect linkage settings.
oil contamination.
did a leakdown test get performed?
compression is a waste of time, have a leakdown test done.

[Zara Spook]

incorrect linkage settings.
oil contamination.
did a leakdown test get performed?
compression is a waste of time, have a leakdown test done.

Appreciate the feedback on that.

Had a marine mechanic tell me that a link and sync should be done only after the carbs have been removed and cleaned. Any truth to that?

[boscoe99]

Appreciate the feedback on that.

Had a marine mechanic tell me that a link and sync should be done only after the carbs have been removed and cleaned. Any truth to that?

A 2004 F150 has no carburetors. Might be time for a new mechanic.

Yes, get a compression test and if needed a differential pressure test performed.

When was the last time the injectors were tested for consistent flow to specifications? What ever the specifications happen to be.

What brand and type of oil is being used?

What is the rate of oil consumption? Same as always or is it up a bit? Could be worn rings, intake valve guides, or...

[99yam40]

Appreciate the feedback on that.

Had a marine mechanic tell me that a link and sync should be done only after the carbs have been removed and cleaned. Any truth to that?

good pics of the plugs are worth a 1000 words if someone is trying to determine what is going on.

seems like I remember not long ago there was a discussion on water causing crusty oil fouled plugs on just one or 2 plugs, but cannot remember what motor or what the title of the thread was.

Oh yea as far as link and sync goes any time someone has been jacking with linkages it needs to be checked would be my thought. that means taking them loose, adjusting things, or what ever they hook up to

[Zara Spook]

Thanks guys -- is there a 2004 four-stroke that's carbed?

This is my stepdad's boat, currently getting serviced. I'm not sure if it's an F150, but I do know it's a 2004 four-stroke.

[99yam40]

not good asking questions about a motor that you do not know what that motor is.
Find out what it is

As I said pics can do wonders

[TownsendsFJR1300]

Just curious, do you know when the plugs were last changed?

[Zara Spook]

Just curious, do you know when the plugs were last changed?

About 18 months ago. Engine gets used about 20 hours a year.

[Zara Spook]

not good asking questions about a motor that you do not know what that motor is.
Find out what it is

As I said pics can do wonders

Sorry -- I assumed that any four-stroke was an "F" engine. I do know it's a 2004 four-stroke with 150 HP.

[TownsendsFJR1300]

About 18 months ago. Engine gets used about 20 hours a year.

I asked in that my 06 F150 4 stroke, (FI'ed) had an issue at about 5,300 RPM's bogging done, as if out of fuel. Keep it below, ran fine. Occasionally, it'd run to 5,900...

I had never changed the plugs (about 180 hours on the engine) and the plugs looked brand new.

Two shops strongly recommended changing them out (that they were over due several times over). Put in new plugs, that was the issue, runs great again.

Something to consider if the plugs are just worn and not as efficient as new, carbonating up, etc..

[Zara Spook]

I asked in that my 06 F150 4 stroke, (FI'ed) had an issue at about 5,300 RPM's bogging done, as if out of fuel. Keep it below, ran fine. Occasionally, it'd run to 5,900...

I had never changed the plugs (about 180 hours on the engine) and the plugs looked brand new.

Two shops strongly recommended changing them out (that they were over due several times over). Put in new plugs, that was the issue, runs great again.

Something to consider if the plugs are just worn and not as efficient as new, carbonating up, etc..

Thanks -- the engine actually hasn't shown any noticeable decrease in performance. This is all stuff that has been discovered only as part of an annual service.

[99yam40]

Sorry -- I assumed that any four-stroke was an "F" engine. I do know it's a 2004 four-stroke with 150 HP.

this is a 2004 F150
see if you can find any carbs in the parts
2004 F150TLRC Yamaha Outboard Parts

Find out what the motor is and post the complete model #

is this even a Yamaha motor?

[Zara Spook]

What I know is that it's a 2004 Yamaha four-stroke with 150 HP. If there is no such thing as a carbed engine of that nature, it must be fuel-injected. If there is a carbed model, it might be that one and not the fuel-injected one.

[TownsendsFJR1300]

Of the ONLY TWO F150's listed here:

2004 Yamaha Outboard Parts

(US versions), BOTH are fuel injected..