2 micron filter question?

[dream catcher]

I have a 225 yamaha OX66 and have had a lot of fuel related problems with VST filters. I was told that replacing my 10 micron filter with a 2 micron filter may help the problem, however, I was also told that using a 2 micron filter could damage the engine? Has anyone switched from a 10 micron filter to a 2 micron filter and if so, have you had any problems? Thanks for any input

 

[DaleH]

See here for a DIY "fuel polishing system" that does use a 2-micron filter withouth adding a fuel restriction to your fuel pump:

http://classicparker.com/phpBB2/viewtopic.php?t=1987

I'd check with your dealer, as a 2m filter in place of your existing 10m filter, WITHOUT an extra pump to pull it through, could cause your motor to run lean and damage it. Some OBs are equipped with vacuum alarms to indicate excessive draw to the fuel pump, but I'm not sure if Yummies are.

 

[TomS]

I've made the switch to a 2 micron and have been running it for about a season and a half without any problems. I run a 1999 Yamaha 0X66.

I had been accumulating that fine gray powder in my VST filter, but was cleaning it out every 100 hours to stay ahead of it and prevent any problems. Now with the 2 micron I feel comfortable cleaning it at the beginning of the season and running it the whole season (average 175-200 engine hours).

I'm not a mechanic, but I believe the potential engine problems could be caused if there is any restriction in the fuel delivery system, generating too much of a vacuum for the low pressure pumps to pull fuel into the engine.

The excessive vacuum could be caused by a clogged filter, accumulated gunk at the fuel pickup tube or anti-siphon valve, etc.. or any combination of the above.

Some people have been successful attaching a fuel vacuum gauge directly onto unused ports on the base of the fuel / water separator to keep an eye on things.

Since its a spin-on replacement for your existing filter, its a no-brainer to try it out if the rest of your engine & fuel delivery system has been properly maintained.

-- Tom

 

[dream catcher]

TomS,

How often do you have to change the 2 micron filter now? Do you have one of the vacum gauges and if so did you install it yoursefl? Thanks for the input, i think i might try the 2 micron, and just keep an eye on it and try not to run engine that hard, I am guessing that the harder the engine runs, the more chance of creating a vacum if there is any fuel restriction?

 

[TomS]

I have been changing the 2 micron filter at the beginning of the season and as part of my 100 hr maintenance. I have not installed a vacuum gauge, so I don't know if that is overkill or not. I figure the $35 I save by not having to purchase a VST gasket offsets the cost of the filter change after 100 hours

If you want some pics and part numbers of people that have installed the gauge, check out the SIM forum on The Hull Truth.

I wouldn't worry about running the engine hard or not.. According to the Racor people, the nominal vacuum across the 2 micron filter is the same as the 10 micron. The difference is that the 2 micron is more likely to get clogged sooner, thus the vacuum increases a little more quickly. Again, if you are keeping on top of the other maintenance on the boat, I wouldn't worry about it.

-- Tom

 

[DaleH]

According to the Racor people, the nominal vacuum across the 2 micron filter is the same as the 10 micron.

That's great info to know! FWIW the draw is measured in inches of Mercury (in-Hg).

Most OEM Service Manuals list the specs and tolerance range thereof.

 

[DaleH]

Yamaha developed the 10 micron specifically for ethanol problems...

That's pretty good :roll: considering Racor had 10-micron fuel/water separators on the market 20+-years earlier ...

 

[dream catcher]

I've made the switch to a 2 micron and have been running it for about a season and a half without any problems. I run a 1999 Yamaha 0X66.

I had been accumulating that fine gray powder in my VST filter, but was cleaning it out every 100 hours to stay ahead of it and prevent any problems. Now with the 2 micron I feel comfortable cleaning it at the beginning of the season and running it the whole season (average 175-200 engine hours).

I'm not a mechanic, but I believe the potential engine problems could be caused if there is any restriction in the fuel delivery system, generating too much of a vacuum for the low pressure pumps to pull fuel into the engine.

The excessive vacuum could be caused by a clogged filter, accumulated gunk at the fuel pickup tube or anti-siphon valve, etc.. or any combination of the above.

Some people have been successful attaching a fuel vacuum gauge directly onto unused ports on the base of the fuel / water separator to keep an eye on things.

Since its a spin-on replacement for your existing filter, its a no-brainer to try it out if the rest of your engine & fuel delivery system has been properly maintained.

-- Tom

What engine do you have? Do you know how the vacum gauge attaches to the fuel water seperator, i don't know anything about them?

 

[TomS]

Go to the SIM forum on thehulltruth.com and look for messages on the 2 micron filters, there are a few different people who have tried this and posted pictures. The one that I thought looked good was a gauge that was directly connected onto an unused port on the Racor head.

-- Tom