Diesel priming on Yanmar 3GM30

[dunedin]

About to replace the fuel filters for the first time since getting the boat.
Installation seems to have an electronic + manual fuel cutoff, then a large in-line fuel filter (Crossland 5005 seems to fit) then the small filter on the engine itself.

Clearly replacing these big fiilters will let an awful lot of air in. So how best to prime the system and get the air out?
* is the little lever just in front of the engine filter the priming pump ?
* where do we start from the line filter then forward ?
* do I need to open a vent at each filter only or right at the injector (assuming I can locate this) ?

And I managed to switch off the fuel input supply with the manual switch under the solenoid, but will I need the engine "ignition" on to allow diesel through to do the priming ?

Apologies for the daft questions, but no manual came so not been able to RTFM !

 

[FWB]

Yanmar Help Forum

 

[alan17]

A lot of bleeding problems can be minimised by sensible location of the filter etc. The full answer to your question will depend on location of these items. On my boat I relocated the filter lower than the fuel tank and fitted shut off taps either side of the main filter. All that I need to do is shut off both taps, change the filter then open the bleed screw on the filter and then open the tap that shuts off the supply to the filter. Fuel then flows by gravity. As soon as fuel comes out of the bleed screw I close that screw and open the tap after the filter and that is it job done, filter changed and bled. If it is feasible on your boat it is worth doing what I have done to facilitate easy, clean filter changing/bleeding even whilst under way.

 

[Cloven]

As alan17 says, a lot depends on where you have your primary filter and whether there is gravity feed. Either way, one way to reduce the amount of air is to fill the filter bowls with fresh fuel before fitting them back on. At least there is that much less to bleed.

I previously had a 1GM 10 and now have a 2GM20 and in both cases the fuel primer is the little lever next to the fuel pump - there is no little lever next to the fuel filter - I expect the 3GM 30 is the same.

I have a copy if the workshop manual which includes the 3GM30 so if you are still stuck, I could get the appropriate pages to you.

 

[jeremyshaw]

Yes, the priming pump is the little lever.

You also need to open the bleed screw on the fuel filter on the engine, after you've bled the Crossland filter.

If your fuel tank is higher than your engine, it's fairly easy as gravity does most of the work I find. A friend struggled with his but solved this by putting a priming bulb (as for an outboard engine fuel tank) inline, and found this made things very much easier.

 

[dunedin]

Superb thanks. Will give it a try next weekend.

Tank is above the filters so gravity should do it. Still can't quite work out whether the electrical solenoid will stop the fuel flow (if not wwhat is it for?)

 

[TheBoatman]

Simple
Replace all the filters. In doing that you would have let air into the system.
If your main filter is below the tank and your batteries are fully charged - undo the engine filter bleed screw and crank the engine - this will draw fuel up through the main filter and when the engine filter runs free of air, tighten it.

Next - open the engine throttle 75%+ - undo the injector pump bleed screw and crank the engine until the fuel is running air free - re-tighten the bleed screw and then the engine will start to fire - at this point keep cranking the engine until it runs away - don't stop cranking as soon as it looks like it wants to go - Important - keep going until the engine revs up and away.

The engine may sound like it's running "roughly" but keep cranking until it "takes off".

Done this many times on a Yanmar 3GM30 and it works first time, every time.

Peter.

 

[dunedin]

Great thanks - currently out of water on props, and yard bans from runing engine. However, will take it as far as I can before firing up. very helpful.

 

[Sam_Salter]

To save priming all the air from both filters, fill the canisters with clean diesel when replacing the filters. That way, you only have a little air to bleed, not the whole volume of the 2 filters.