Yanmar secondary filter location

[Jalepeno]

I posted this over at the "Engines and Propulsion" forum last week. Had 231 views but not one reply.

The secondary fuel filter on my Yanmar YSM12 is located behind the alternator and above the starter with very limited and difficult access, resulting in a very messy filter change. I'm considering relocating it to the port bulkhead near the Racor primary filter. I would then use hoses to connect it to the Yanmar mechanical lift pump and the high-pressure injector pump.


Has anyone done something similar?


What are your thoughts?

 

[RichH]

You can locate this 'engine guard filter' (~15-17µM) anywhere you want (as close to to the engine as possible) ... except that it has to be at the very highest point of the whole fuel delivery system .... so all the air/gas bubbles will collect in the top of the filter housing, and that you can easily 'bleed' the filter housing via it's bleed screw.

To bleed the engine 'guard' filter in this 'highest' position you will need the mechanical engine lift pump to have a 'hand pump bail' to manually actuate the lift pump diaphragm when the engine is not running .... or a 12vdc pump somewhere in the fuel delivery system (best is nearest to the fuel tank (and with the 12vdc pump protected by a small 'strainer'); the 12vdc pump operated with a 'push button' switch(s) mounted conveniently near each filter housing to make 'bleeding' filters and fuel lines VERY easy. (a constant 'on' switch for the 12vdc pump will be in 'reserve' when/if the engine lift pump ever fails.)

If you mount this filter to a bulkhead, etc. ..... for the 'soft connection' to the engine, I'd suggest going to a hydraulics shop and obtain diesel resistant (including resistance to reclaimed 'bio-diesel') double walled and ARMORED (looks like bare co-ax cable) .... 'aircraft grade' hosing. NO 'compression fittings on copper tube' ... double flared or 'better'.

 

[Steve Dion]

I would leave it where it is. The filter probably does not need to be changed but once every 500 hours. So chances are that is once every 5 years or less.

 

[Benny17441]

I would reposition it but would leave it attached to the engine. I would not want having those fuel hoses flexing back and forth.

 

[RichH]

Make it convenient for yourself. If the filter is not convenient to change out you wont change out. Such filters are only 'reasonably' left in service for 1 year max. as any emulsified or free water will be absorbed by the filter media. Water absorption in resinated cellulosic filter material can 'soften' or digest the filter media ... and since this is a 'last chance' or 'guard' filter (NOT a so-called 'secondary' filter), its integrity is quite important. Most of such filters in a fuel delivery system should be changed out -- yearly.

 

[Eric M]

The previous owner of our boat removed the mecanical lift pump and engine mounted filter from our Yanmar 3GM almost 1000 engine hours ago now. Fuel leaves the tank, heads to the constant on when ignition on 12vdc pump, then to the primary (actually a pair in parallel with a 3 way valve to select one or the other), then to the secondary and finally to the high pressure pump inlet. All plumbing is done as Rich H recommended with hoses made up at a hydraulic shop and all the above hardware is mounted on a bulkhead where access is convienent. (Well as convienent as anything can be on a sailboat) The key fitting is the banjo fitting at the connection to the HP pump on the engine. Crack that fitting open, ignition on, wait for fuel to appear, tighten and the engine fires right up. When the primary filter plugs I can throw the valve to the second primary, open the banjo fitting and have the engine running again in usually 30 seconds or less. You can then change the plugged primary at a more convienent time. As I mentioned above, this setup has worked well for over 1000 engine hours now.