Yamaha "F" filter question

[marchmadness]

03 f225
What does the F filter do? I was reading om another forum that someone cut a old F filter apart and there was nothing inside!

[boscoe99]

You must have read that over at The Hull Truth.

Where truth is seldom heard, but the disparaging word, is often heard.

[fairdeal]

Personally I think of it more of a "screen" than a "filter"
but here is what an "F Filter' looks like cut apart.

(According to Yamaha, this all-white part is rated at 40 microns
the later part has a blue end, that is 32 micron)

[marchmadness]

So this design wasn't by accident! It seems the blue end ones have been referred to as a Vapor separator filter. Yamaha had to engineer this filter , it would have been an easier way to supply the fuel to the vst.

[pstephens46]

What is the issue?

[marchmadness]

Right now there is no issue ! The boat is away for a long winters nap. In short I have had a long battle with fuel starvation( I have a very long post about this) So before I unwrap the boat in April I am still trying to get some answers. So I was wondering if there was a reason for the F filter

[fairdeal]

Yamaha had to engineer this filter , it would have been an easier way to supply the fuel to the vst.

Yes, I do marvel a bit at how many years it took for Yamaha to have that screen
- and the pressure control valve -
incorporated directly into the VST itself.

(More egregious, is that they continued to use that tiny HP pump screen for a decade...)

Post- 2010 F225 VST:

[99yam40]

Does it seem strange to anyone that the normal water separator/filter is 10 Micron, but this F filter is 40? what are they trying to catch with this screen?
what Micron is the screen in the VST and the injectors?

[fairdeal]

what are they trying to catch with this screen?
what Micron is the screen in the VST and the injectors?

The screen is downstream of the lift pump - so presumably to catch particles generated by the pump?
Rodbolt often talks of 'brush dust' - but I imagine that to be extremely fine.

The screen for the high pressure pump intake has varied substantially by model;

the part for the 2000-2010 F115 and 2002-2010 F200/F225 is eyeball-popping course -
no doubt to compensate for it also being ludicrously small in surface area.

One can actually count the 'pores' with a few 'X" magnification -
I estimate the 'micron rating' to be > 200 microns


I have never found a reference to the 'micron' rating of the typical injector 'basket filter' -
but I would like to know it...



the F225 'f-filter' screen pictured alongside the F225 HP pump screen:





closeup of the two:





the HP pump screen scaled for dimension:

[marchmadness]

So to answer my question the F filter is a fine mesh screen that is meant to pick up debris that might be caused by the lift pump or that got passed the water separator filter, and the engine cup filter. By the way the pictures really show the difference in the filters.

[99yam40]

I guess if you catch the big stuff with the larger micron screens there is less to plug up the smaller micron ones down the line.
How often do the F filters need to be replaced?
maybe wait until there is a noticeable problem?

maybe cleaning the VST and changing the F filter on a regular basis would be a good idea

[boscoe99]

It seems to me that the fuel systems for the various models are either designed by different companies for Yamaha or by different design groups within Yamaha. Amazing to me the variances that exist across the different models.

[pstephens46]

I guess if you catch the big stuff with the larger micron screens there is less to plug up the smaller micron ones down the line.
How often do the F filters need to be replaced?
maybe wait until there is a noticeable problem?

maybe cleaning the VST and changing the F filter on a regular basis would be a good idea

From a diagnostic standpoint, I wonder if enough solvent can be shot backward through the F filter to dislodge gunk. About a $35 part for me. Not bad but still....

[99yam40]

will solvent get carbon brush dust out?
I am sure it will not dissolve it.

Maybe you could rig up a flow tester to hook it up to to make sure it flows enough, and then also flow it backwards to see if you could flush anything out and then recheck flow.

But rigging that type of system up could be costly and more of your time than just replacing with a new one.

[marchmadness]

I don't think this is a yearly thing but every other year might be good. I think I will replace it and cut it open and see what kind of crud is inside. The newer model is a 32 micron maybe use that instead of the 40?