Yamaha VST & HP Filter Change

[flounderpounder225]

The following may be a worthy post for any HPDI or OX-66 owners in our midst.  As most know, I have dealt with a great degree of fuel quality issues since Splashing Marc-Time, from the initial purchase and hanging/rigging and sea trial and then later on with massive contamination issues, where I had to be towed in from off-shore.  These DFI engines, are very particular about receiving clean, unobstructed fuel, and when they don't get their way, they let you know.  After my most recent tank cleaning and fuel polishing, which still has my Racor Clear Bowl pristine looking   , I never changed my VST or in-line HP filter, I thought my racor and engine mounted filter took the brunt of the abuse, Wrong... last Sunday she would fall on her face when attemtping WOT, I knew the signs... VST Clog.  Well, rather than a $300+ bill at the dealer, I did it, the VST is very simple to remove and drop the bowl, detach the filter element at the bottom of the LP Pump, the screen was absolutely nasty, from the water contamination, and crap that WAS in my fuel tank, I cut the old/used HP stainless canister open (which is after the VST and inline before the HP pump), and the internal element was black.  A #2 Phillips screwdriver and metric 1/4" socket set is all you need.  There is a great post over on THT about this, and also about replacing some small micro-basket filters which reside in the HP pump, which will be one of my winter little projects.  I have not water tested her yet, but by the way she busted off and ran smooth on the hose, I expect full power back this weekend.  Here is the THT link
Have a great weekend.
Marc

http://www.thehulltruth.com/boating-for ... rt-ii.html
http://www.thehulltruth.com/boating-for ... otors.html
http://www.tidalfish.com/forums/showthr ... VST-filter

[seabob4]

Marc,
I just did a VST filter and HP filter change on a 250 HPDI, have to remove the whole housing (3 bolts) from the P/H to get the top plate off without fear of dropping the retaining bolts (bunch of them!) down by the powerhead...correct?  Even had a service manual, didn't say squat about that...

[flounderpounder225]

Correct, the manual assumes you already know that the three bolts have to be removed, how about those vibration isolator mounts.... think they could have come up with something a little more elaborate ?   A couple of mine came all apart, and that was the one thing I had to get the manual out for, to see the order of all the pieces as they went back in.  One of my perimeter small screws was already missing, where my "local" Yamaha dealer's mechs lost one obviously on the last change out, cause their the only ones who have ever touched it.  And the O-Ring was just a little fun keeping it in the groove even with a little grease, I reused mine.  A tip from the mech at my dealer, for normal service where the VST screen is not nasty: remove it as normal, then "pop" it out of the plastic round holder using a small flat blade screwdriver or pen knife, you can spray it with carb cleaner and put it back in, save you 40 bucks...

Overall, very easy job, and way over-rated for complexity by the dealer, this is something most (some folks shouldn't mess with fuel systems) HPDI or OX-66 owners really need to learn to do by themselves, and save weeks off the water and about $200 in labor.

[seabob4]

Marc, you're right about it being an easy job.  As far as keeping those anti-vibration washers/bushings (real bright setup, huh?) in the proper order, I pulled the first one and laid all the pieces, in the correct order, off to one side, then used that as a guide when putting everything back together...

[flounderpounder225]

well, I took her out for a quick 10 min run yesterday, she is running ok, no more huge stumble at WOT and falling on her face, but I still have the small surging at WOT and not hitting my 55-5600 that I was a year ago, after the new prop and engine work, so it confirms that I need to get into those micro basket filters in the HP pump, hopefully that will be the solution, and the injectors are all good to go.  Sure am learning alot about this DFI system...  

[John Jones]

Sure am learning alot about this DFI system...  

 
and saving yourself a ton of money.

[seabob4]

You know, I got a Yamaha GENUINE diagnostic CD from a buddy down under...I need to see what's on it...

[flounderpounder225]

Ok, it's not winter yet... but I tore into the HP pump this afternoon, very daunting experience considering the price to replace, but all good now, I have pics and will try to explain as I went, really, not bad.   Ok, first, you have to remove the flywheel cover and rear coil pack covers, not hard, and not going to explain that, once that is done this is what your looking at, NOTE: The HP Pump is at the top of the motor, in this pic I have already removed the 4 bolts holding the cover assy. to the port side of the pump assy.  I only did this side this afternoon to see if I could find and remove these basket filters, in the next few pics I am moving in from far away, to up close so you can see the detail of where I was working and removing this filter






Screw #10  Stainless screwed a few turns in, and wiggle the filter out


Now after I thought I was ruining my 2K Pump by driving a stainless wood screw into it, but the nasty little filter finally popped out, it was time for celebration...  


There will be more to follow, as I have to find these filters somewhere, there not an OEM item.

[flounderpounder225]

Ordered the micro basket filters today http://injector-rehab.com/shop/Bosch-Un ... asket.html more to follow after I get them and install.

[flounderpounder225]

Just wanted to update, changed the mini filters in the HP Pump, very simple.  Took it out this afternoon and noted a definite improvement, gained 3 MPH and about 300-400 RPM at WOT, back to 5400-5600 WOT depending on trim, very rough water today with 25-30 kn winds from this depression.  Invaluable knowledge for any HPDI owner.
Marc

[seabob4]

Marc,

Your post is invaluable to any HPDI owner out there, Aquasport or not!  Well done, my friend!!!    

[jdupree]

Great post Marc The VST instructions will come in handy for my OX-66.  By the way, this OX-66 is the best running engine I have ever had!!!!  Quite as well.  Thanks for the insight on these motors  Glad yours is where you want her