[C320-list] More Yanmar 3GM30F Questions

[Jeff Church]

Mike,

 

I'll take a shot at this, but I'm working from memory so someone might have to correct some details.

 

First, adding biocide is a good practice. I put some in the tank at the first fill of the season and again at the final fill of the season. The local Yanmar rep also recommends using Cetane booster because of the poor quality diesel that is generally available.

 

When you replace the primary (Racor) filter use the 30 micron R15P filter canister. The secondary filter is a Yanmar part #104500 55710.

 

You probably should close the fuel valve at the top of the tank before removing the old filters, but I think there is a one-way valve in the primary filter bracket that would prevent any fuel flow absent suction from the pump. Put a 1 gallon plastic bag around the primary filter to minimize spills when you remove it. If you are a belt and suspenders type, you can also fashion a tin foil pan underneath it. You might need to use a strap wrench to remove the filter from the filter bracket and again to remove the bowl from the filter. On my boat the filter is mounted so close to the hull that I have to unbolt the filter bracket in order to remove the filter.  



Changing the secondary filter is fairly straight forward. Unscrew the collar, remove the bowl, install the new element and gaskets, and mop up the spilled fuel.

 

You can try to pre-fill the new primary filter before attaching it, but I find that difficult to do without spilling. Once the new filters are in place, open the valve at the tank, unscrew the priming pump at the top of the primary filter bracket, and loosen the banjo fitting at the intake side of the fuel pump. Operate the priming pump until the primary filter is full and fuel flows past the banjo fitting without any air bubbles. Re-tighten the banjo fitting and the priming pump. The rest of the system is bled by operating the priming pump handle located on the fuel pump. Loosen the bleed screw on top of the secondary filter, and operate the priming pump handle until all the air is purged. Tighten the bleed screw. There is another bleed screw on the injector pump. Open it and operate the priming pump again until all the air is purged. Tighten the bleed screw. At this point the system is bled up to the injectors, and I usually start the engine and check to see how it operates. 

 

The engine will probably start fairly quickly, but if it cranks more than the recommended amount of time, drain the muffler. Once it is started it probably will idle, but it might not run properly under load. Put it in gear and make sure that it will operate under load. If not, let it run in neutral for 10 minutes and occasionally rev it up. If that doesn't clear the injectors, they will need to be bled. Stop the engine, leave the kill switch pulled out, and position the throttle at full speed. Loosen the flare (tubing) nut at the first injector and operate the starter for a few seconds until the air is purged. Re-tighten the flare nut. Drain the muffler if you have to crank the engine too long (doubtful). Repeat for the 2 other injectors.

 

Good luck

 

JeffC    

  ----- Original Message ----- 
  From: mike hunter 
  To: C320-List 
  Sent: Tuesday, March 20, 2007 4:24 PM
  Subject: [C320-list] More Yanmar 3GM30F Questions


  I want to start by thanking everyone involved with this mail list.  It is a blessing for novices such as myself.  I have a fair understanding of gasoline engines after owning a few Volkswagens during my younger years.  They have a way of forcing you to learn.  However, my knowledge of diesel engines is poor, particularly when it comes to the fuel system.  From what I've read it seems the key to a well running diesel is clean fuel.  I've added the biocide treatment and inspected the water/fuel separator under the primary filter - which is clean.  I plan on replacing the filters this season, but I want to be squared away first; as I'm concerned about bleeding the injectors incorrectly and for too long, and ultimately backfilling the motor with seawater.  Would someone be so kind as to break down the steps of replacing them? 
     
    Also, how often should biocide be added to the fuel system for maintenance treatments?
     
    Thank you!!!
     
    Mike
  #637  

   
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