Yanmars and 2 Micron filters in Racors?

[CarlF]

I know this topic has been kicked around a bunch but I had a personal experience that makes me rethink my practice.

Crossing back from the Bahamas my Yanmar 4JH4 suddenly would not go any faster than 2000 RPM. Sounded fine just no speed. A quick look at suction gauge on the dual Racor showed no problem. Switching to the spare Racor filter didn't help. Switching fuel tanks didn't help.

While it "had" to be fuel, my secondary engine mounted filter is in a terrible location to replace offshore so we headed for shore to replace it. Replacing the secondary filter did fix everything. I also replaced both Racor primaries even though they were looking only a little dirty (and still no pressure on the gauge). Also no water or crud in the bowls.

My current assumption is that the last fuel I took on at Marsh Harbor had a lot of sediment that was smaller than the 10 micron Racor filter size but got caught in the secondary. And Yanmar doesn't say what the micron size is on this filter.

So three questions:

Does my Marsh Harbor fuel theory make any sense?

Might I have done any damage to anything by running for eight hours at 2000 RPM in this fuel starved condition? (not much wind but a lot of sea, of course )


Should I switch to a 2 micron filters in the Racors? Even though they would clog quicker, I then have a gauge to diagnose the problem, a lever to switch filters, and they are a snap to change even at sea. The Yanmar manual says I shouldn't use anything smaller than 30 microns (although I normally use 10s).

Carl

[callistov42]

I run 2 microns in my Racors on my 4JH5E.
Like you say, changing the primary is a LOT tougher than flipping the lever and cutting in the spare Racor. Never had a problem doing this. Still, maybe one a year or so, I get a fuel problem that is resolved by changing out the primary (on engine Yanmar filter).

[ebaugh]

I run 2 micron Racor pre filters on my Lehman 120's. Never had a problem with the primaries, replace them about once a year. Not sure this is the best practice, but it works for our 1985 trawler so far. I used to get 300-400 hours out of a primary. Since getting fuel in Colombia, it's been more like 50-60 hours, but is trending back up now.

[djmarchand]

I guess it is a "you pays your money and you takes your chances" type thing. If you have plenty of Racor cartridges and it is easy to monitor pressure drop, switch when it goes up and replace the filter, then I would be tempted to go with 2 micron in the Racor.

2 micron in your primary is going to plug up sooner than 10 or 30, but if it is easy to replace the primary and tough (and somewhat more expensive) to replace the secondary then go with 2 micron in your primary.

David

[CAELESTIS]

You need to run the Yanmar at 2700-2800 RPM for 15 minutes every 4-5 hours. Running at low rpm to save fuel can carbon up the injectors on a 4JH4.

[captain58sailin]

I have run the 10 micron racor / 2 micron engine secondary, I have only changed my 2 micron once a year. I thought that it would provide extra protection to my engine if I ran 2 micron racors, so I switched over, but I haven't run enough yet to determine if it will help or just become a big pain to constantly change filters. I did install a passive centrifuge up stream of the filters in hopes of slowing down the clogging of the filters. I should have more intel come this summer.

[MarkJ]

I use 2 micron in my Racor.

[Kettlewell]

I didn't even realize I was running 2 Micron filters in my Racor as I had purchased some 10s and didn't notice that the last of the old lot were 2s. I didn't have any issues at all, and I was running a lot of fuel through them at the time (ICW). I think I read somewhere that a CAV, which is what I have on the engine as a secondary, is about 5 microns. Anyone know for sure?

[onestepcsy37]

the engine fuel filter on the perkins 4-108 is a bitch to replace. so i run 2 microns in the racor 500, which is easy to replace, and i replace it every 100 hours. i think the engine mounted filter is 30 microns, which i replace once a year, just to keep in practice.

i've bought diesel in marsh harbor and had no problems, but i don't have it pumped in. i jerry jug it and then siphon it into the tank through a baja filter. knowing that most diesel problems are fuel related i guess i'm a bit anal about it, but since i don't burn much fuel it's not too difficult. i guess if i had a trawler with 500 gallon fuel tanks it might be different....

[Rakuflames]

Originally Posted by CarlF

I know this topic has been kicked around a bunch but I had a personal experience that makes me rethink my practice.

Crossing back from the Bahamas my Yanmar 4JH4 suddenly would not go any faster than 2000 RPM. Sounded fine just no speed. A quick look at suction gauge on the dual Racor showed no problem. Switching to the spare Racor filter didn't help. Switching fuel tanks didn't help.

While it "had" to be fuel, my secondary engine mounted filter is in a terrible location to replace offshore so we headed for shore to replace it. Replacing the secondary filter did fix everything. I also replaced both Racor primaries even though they were looking only a little dirty (and still no pressure on the gauge). Also no water or crud in the bowls.

My current assumption is that the last fuel I took on at Marsh Harbor had a lot of sediment that was smaller than the 10 micron Racor filter size but got caught in the secondary. And Yanmar doesn't say what the micron size is on this filter.

So three questions:

Does my Marsh Harbor fuel theory make any sense?

Might I have done any damage to anything by running for eight hours at 2000 RPM in this fuel starved condition? (not much wind but a lot of sea, of course )


Should I switch to a 2 micron filters in the Racors? Even though they would clog quicker, I then have a gauge to diagnose the problem, a lever to switch filters, and they are a snap to change even at sea. The Yanmar manual says I shouldn't use anything smaller than 30 microns (although I normally use 10s).

Carl

I use 2 micron filters, and had exactly the same experience, although my dirt came from a dirty tank. I have external filters I put in the fuel port if I'm getting fuel from an unknown supplier. But I really don't remember what micron size it is.

Is there any chance there was dirt on the sides of your tank that got shaken loose in the seas? That happened to a friend of mine.

[Kettlewell]

Here's what Racor writes:

Racor’s 2 micron filter medium should only be used
in final or secondary filters where the fuel is first
filtered by a primary filter. The primary filter for a 2
micron final filter should use a 10 micron medium.
The exception in using a 2 micron filter in place
of a primary filter is to obtain high-efficiency water
separation, and is usually used in marine applications
where the fuel supply may be cleaner but also may
contain water more often. If the installation can allow
the use of a filter large enough, then a 2 micron filter
can serve in a system as the only filter in that system.

[Rhapsody-NS27]

I don't know what my racors have now but I found that I have 30micron spares but reading this thread, I wonder if I should just go ahead and order 10 (which was my original idea) or 2.

Looks like, either way I go, I'll still be good.

[CarlF]

It's always possible that the stuff came from the tank. The seas were sloppy. But this was the first fuel problem ever for this boat (I use biocide at each fill). I'm still surprised how clean the 10 micron Racors looked with a completely clogged secondary.

Thanks for all the response. It looks like using 2 micron Racors is a reasonable approach given my setup.

Carl

[callistov42]

Captain58sailin...
You mentioned installing a passive centrifuge upstream. I have been fighting a problem with water in one tank, limited access to polish the fuel so I had a Mechanical Line Solutions Fuel Purifier installed ahead of my Racors just recently. I think it also a passive centrifuge. Has yous been beneficial?

[captain58sailin]

So far, I have not been able to use it enough to determine if it is effective or not, when I was crossing the gulf of Alaska, I had some pretty nasty stuff clog up my racors, and I used so many that I was concerned with running out. So when I got to Homer, I started a refit, part of which was revamping the entire fuel system, I have only run my gen set through centrifuge and I am in the process of swapping my main engine out, once that is completed, I will run some sea trials and be able to report back here as to its effectiveness. The logic seems sound, we will see if it actually works or if I blew $750.00 on snake oil. I will report back on this site once I get a chance to really find out if it works, or not.