2 micron or stick with my 10 micron fuel filter on the HPDI?

[BTF112989]

So on my last 3 trips out, my Yamaha 150 HPDI has stumbled for just a second while getting up on plane or if I am cruising over 3500rpms.  I've had my fair share of fuel filter issues with this engine back in 2006, and I learned how to manage them quickly.  After numerous VST filters, medium pressure filters, water/fuel separating filters, I decided to get a big external water/fuel separator.  I've always used the Yamaha 10 micron filter with no real problems, however this last time I went cheap & bought the sierra filter.  Since the engine is surging slightly & I haven't replaced all of the other filters mentioned above in 100+ hours, I am doing a total filter replacement.  I am buying a medium pressure filter, water/fuel separating filter within the engine, the little basket filters near the high pressure pump, the VST filter, and a new external water/fuel separating filter.  Since I am doing it all at once, I am wondering what to do in regards to my external filter.  Should I go back to the old reliable Yamaha 10 micron I have used all along?  Should I switch to the Racor 10 micron filter with the clear bowl at the bottom(I like the idea of seeing water in the bowl & being able to drain it out)?  Or switch to a Racor 2 micron filter with the clear bowl?

I realize some people say that a 2 micron filter is much more restrictive & makes the fuel pumps work harder, but other people on THT say they run them on four strokes, HPDI, etc with no issues.  I just like replacing the external filter for $20 instead of spending $75 on the medium pressure filter each time.  Do you think the 2 micron would give me any added benefit, or is it more risky/detrimental than its more?  

I realize some people say the 2 micron will get clogged more often than the 10 micron & that is a little more of a hassle, but if its clogging up, then its doing its job in my eyes.  These HPDI engines get really cranky when they don't have very clean fuel.

Cliff notes:
Yamaha or Racor?
If Racor, 10 micron or 2 micron?

Thanks,
Ben

[fitz73222]

Your engine should be able to swallow anything under 10 microns without any issues. 10 microns is a very small media size. It would not be practical or safe to design an engine with such a finicky fuel requirement.  You know your engine better than anyone. This I can tell you from my experience from running 10 micron filters on my engines is that I change them once a year, regardless of hours and every two years I change the under cowl engine filters and in my analness I cut the under cowl filters in half to see what is in them and invariably I see nothing inside them (like new!) and wonder why I changed them. So it tells me the 10 Micron is doing its job. I use either Parker or Moeller 10 micron filters, stainless steel housings, and the clear site bowl design. I run E10 fuel with startron and have yet to find a drop of water in either one and the boat will sit for months under cover outside in Florida and fire up and not miss a lick. I think you will like those filters.

Fitz

[flounderpounder225]

Boy can I elaborate on this topic    I have been all the way through my fuel system, including the micro-basket filters on the HP pump.  That, along with my fuel tank cleaning (polishing) and the other filters solved all my fuel issues.  Yes, HPDIs are very finicky about fuel cleanliness.  I run the racor 10 Mic with clear bowl for a visual, I think that is all you really need.  If you need any advice on replacing the "basket filters" on the HP pump, let me know, I have done 2 HPDis so far, mine (250 HP) and a 200.  Pretty straight forward.  But just for information, according to my local Yami dealer and friend, the filtration inside the engine, I think its the Med pressure filter (the one going to the HP pump) is a 5 micron filter, so your 10 Mic Racor is not the finest degree of fltering before the engine gets the fuel, and the baskets may also be 5 micron?

[BTF112989]

I will go with the Racor filter with the clear bowl then.  I run startron & ring-free on every fill up as well.  

Flounderpounder,
Your post & a post on THT inspired me to want to do the basket filters.  I've heard the medium pressure filter( the expensive one) is 5 microns too, so that was the basis for me asking about the 2 micron filter.  Its easier to replace a $26 2 micron filter than the $75 medium pressure filter.  I think the VST basket filter is 10 microns.  I gained most of my filter knowledge when this engine was on my old boat with an older,dirtier tank.  I think I may also need to replace one if not both of my low pressure fuel pumps because my engine starts up fine when cold, however it is a little rough & blows out a good cloud of smoke for a little while.  After being run around for awhile, it sometimes takes 2-3 starts to get her going & the same cloud of blue smoke shoots out for about 10 seconds.

[HIFLUTIN]

Make sure you see your fuel condition at a quick glance.
You know any little bit of water can choke you up.
I run one of those cheepo see thru-Adwood/Wally world filters the I can easily see.
Might not Filter much but you can see whats goin on fuel wise

[flounderpounder225]

I could be off base a little, but I don't think the hard start is a LP pump.  Remember the low pressure pump just lifts the fuel to the VST, then when the VST full the float shuts the fuel off until the level drops, much like the float in a toilet tank.  Then that fuel is passed to the HP pump from the VST  pump which is very much like the in tank pumps in our cars today.  Assuming the VST is full when you shut the engine down, start up would come straight from the VST pump and downstream to the HP PUMP.  you might want to post this issue over on THT, there some good info on the HPDI engines as you have already seen.  Sounds like low fuel pressure at the injectors so it's not atomizing the fuel properly, and the oil injection is coming on as normal, so when she does bust off, your burning the excess fuel oil mix until it clears up.

[skyliner4444]

I read many posts pro and con on the use of 2 micron vs 10 and decided to try the 2 micron on my 2004 200 hp OX66 because the VST filter kept getting coated with a residue and I figured it would be cheaper and less time consuming replacing the seperating filter. The flow rate was the same at 60 gph.  I believe the consensus was to replace at 50 hrs. I've been out a couple of times and it runs great, no fuel starvation. I brought along a 10 micron just in case. The OX66 may be more forgiving than the HPDI? So far so good.