Bleeding Yanmar

May 18, 2017
66
Hunter 44 Changes
The diagram provided to me is difficult to read/faded. I changed the Raycor, primary filter as instructed and the engine won't start. I had read the Yanmar 4JH4E was self-priming (although, now have found other posts which indicate it is not). I need to bleed the line. I'd like to confirm which of the 3 bolts atop the secondary filter is the air bleed? One diagram appears to show the middle one, but I'd appreciate confirmation.

Also, do you know how long it typically takes to pump the air through? I refilled the Raycor bowl with fresh diesel (tank if full).
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
Not the same Yanmar engine as yours, but my bleed screw was the one with the phillips head.
I recently had to replace the whole housing because the screw was stripped and leaking fuel everywhere. The dealer said it was common to overtighten them. The washer wears out and the threads pull.
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
That picture shows a hand using either a nut runner or a screwdriver but calls out the bolt as a hex head. In my case the bolt (screw) has a hex head with a phillips cut into it too. Less likely to overtighten with a screwdriver.
 
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NYSail

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Jan 6, 2006
3,049
Beneteau 423 Mt. Sinai, NY
When you changed the filter did you fill the canister with fuel first?? What Racor do you have? I have the 4JH4E and while it is not self priming, it is self bleeding once you fill the filter canisters with fuel. Fill the Racor then crack the bleed screw at the high pressure injector pump and manually pump from the fuel pump until you see a bit of fuel coming out. Tighten things up and then go ahead and start and it should run fine.

Good Luck!

Greg
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
Pumped it at least 100 times, still engine will not turn over.
Won't turn over or start? If it won't turn over, then the problem isn't bleeding the fuel line, it is electrical in the starting circuit.

If the fuel isn't getting to the pump, there may be an air leak somewhere. Double check all the hose fittings before the lift pump. Make sure the filter is assembly is tight. For a while there was an issue with Racor 500 filters. The design was changed and the new filter elements did not work in old filter housings. That has been resolved now with yet another new filter element design.

Take the outlet hose off the lift pump and try pumping, you should get fuel quickly. And just for grins, check to make sure the fuel shut off valve isn't shut off. (been there done that. Why won't my snowblower start???? Duh!)

Follow the hose from the lift pump and loosen the fitting and pump some more. Keep working your way down the system.
 
Jun 2, 2011
347
Hunter H33 Port Credit Harbour, ON.
Justin is correct. The bleed screw is on the banjo fitting where the unpainted hose is connected. Ideally the bleed is at the highest point in the fuel system before the high pressure injection pump. It is unclear though where the fuel is being fed from. Usually there is a feed to the filter from the fuel lift pump but the unpainted line would indicate that it is a line that runs from the fuel tank, possibly via the water separator. (Supplied by the boat manufacturer)
If the high pressure pump has air in the system, caused by trying to start the engine with no fuel in the filters, it may be necessary to bleed the injection pump also. You may have to loosen the connections at the injectors and roll the engine over in order to force the air out of the system at the injector connections. If you do this turn off the cooling water supply so you don't force water into the engine.
 
May 18, 2017
66
Hunter 44 Changes
It is turning over but not starting. Only the primary filter was touched and changed. Was working flawlessly until this maintenance.
 

Gunni

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Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Also, do you know how long it typically takes to pump the air through? I refilled the Raycor bowl with fresh diesel (tank if full).
Using that little priming pump lever? About 3 days :tongue:
Does your Racor have the priming pump on it? That moves more fuel and will fill the filter body and move the fuel to the secondary filter bleeder. Once you have all fuel (no bubbles) there, you should be able to start it. If not you have to start loosening injector nuts. Generally the engine is self priming once you get all fuel to the engine filter.
 
Jul 7, 2004
8,402
Hunter 30T Cheney, KS
It is turning over but not starting. Only the primary filter was touched and changed. Was working flawlessly until this maintenance.
Sounds about right. Diesels don't tolerate any air in the system
 
Jun 2, 2011
347
Hunter H33 Port Credit Harbour, ON.
Pumped it at least 100 times, still engine will not turn over.
For some reason I did not see this post before the first reply. If the engine won't turn over it may be hydro-locked. I hope not but that is what could happen if water enters the engine.
The lift pump is driven by a lobe on the camshaft. If the engine stops with the internal leaver on the high side of the cam lobe the pump diaphragm will be in the depressed position. Th manual lever will not work the diaphragm in this position and the pump will not move any fuel. In order to rectify this the engine needs to be bumped over a little to get the internal leaver off the cam lobe. You can feel a noticeable difference on the mechanical leaver. With the bleed screw open there should be a lot of fuel coming out when you pump the fuel pump leaver.
 

NYSail

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Jan 6, 2006
3,049
Beneteau 423 Mt. Sinai, NY
Did you fill the filter housing BEFORE you put it together? If you did not you will be pumping that little lever till the cows come home..... This engine once filter is primed will turn over and will self bleed. Also make sure you shut off engine water feed or you will flood the engine with all the cranking. Just make sure you open immediately after engine turns over.
When I replaced my racor from a 110 to a 500 and also replaced all fuel lines once I primed filters, the opened the bleed on top of the secondary filter and pumped a few times engine turned over relatively quickly
Good luck
 
Jan 7, 2011
4,727
Oday 322 East Chicago, IN
I change denier both the primary (Groco) and secondary filters on my Yanmar 2GM20 this year (first time since I bought the boat 4 years ago).

Filled both filters after putting in the new elements, and started the engine. Did not even have to bleed.

Also, make sure you turn the valve off at the fuel tank before starting, and open the valve when you are done. (Wouldn’t that be embarrassing !)

Are the filters installed tightly ( o-rings in place, not cocked, etc.)?

Greg
 
May 18, 2017
66
Hunter 44 Changes
Yes installed properly. Doubled checked today. Still not starting.
Raycor primary filled to the rim with diesel.
 
May 18, 2017
66
Hunter 44 Changes
No, does not have the priming pump on top. Housing was filled to the top. Loosened two injector nuts, all diesel. Still not starting. Never heard or have had to keep the water intake closed. That's not a listed step in the operator manual where it gives high level steps to prime.