Yanmar 4JH4E - Bleeding Air after Fuel Filter Change

[dkinzer]

I got around to changing the primary and secondary fuel filters on the Yanmar 4JH4E on our Hunter 41DS. I've owned diesel trucks for years and successfully changed fuel filters with no problem. But on this, the first filter change since we got the boat, I'm not having any luck getting the engine to start. It fires right away and then quits.

I've attached photos of the primary and secondary filters. The primary is a Racor 230R2 with a R20T filter. The image is actually an R215R2 but it's the best image that I could find online that is similar to the 230R2 that I have. On the Racor filter image I've circled the priming pump knob in blue and the bleed screw in yellow. After installing both new filters, I opened the fuel tank petcock and backed out the bleed screw on the Racor and pumped away on the primer plunger until I was getting bubble-free diesel coming out of the bleed screw and then tightened both the primer plunger and the bleed screw.

Then, I moved on to the secondary filter, a photo of which is attached. The screw that is circled in yellow was loosened and I pumped fuel using the manual lever of the lift pump until I got bubble-free diesel coming out.

With the raw water intake closed, I attempted to start the engine. Although the engine did fire right away it died in a few seconds and it would do this on every start attempt. I went back and bled the secondary filter some more and got some bubbles but they cleared quickly. Attempting to start the engine produced the same response.

I would like some feedback on whether or not what I did was correct and, if not, what I should have done. Secondly, I'd like some advice on what to try next. Perhaps the injector lines need to be bled, too?

 

[Terry Cox]

I've never had a starting problem with our 4JH2-TE after changing the filters. I do make it a point to fill the new filter and bowl with fresh fuel before closing. Usually starts and tuns after just a few turnovers. Our engine also has a manual lift pump next to the engine spin on fuel filter. I actuate it several times until I get some resistance that indicates fuel is getting to the engine.

 

[Don S/V ILLusion]

the most likely cause after changing the secondary filter is air in the line between the secondary and injectors. Simply priming the filter won’t fix that.

what you should do is bleed the injectors beginning with the first one. It should then fire after which the fuel flow will effectively bleed the remaining injector lines.

 

[dkinzer]

I do make it a point to fill the new filter and bowl with fresh fuel before closing.

Yes, I would have liked to do that, too, but I didn't have any suitably filtered fuel on hand.

 

[dkinzer]

you should [...] bleed the injectors beginning with the first one.

That was going to be the next thing to try but I ran out of time today. I suppose that I'll need to make a remote starter switch so that I can do it by myself.

 

[Paul Mermelstein]

I used to do all that on my 4JH3E until a mechanic that I trust told me Yanmars don't need to be bled if you filled up the secondary filter. I was incredulous but his explanation was that normally the excess fuel that is not going into the cylinders goes back to the tank so if there are air bubbles they will quickly be expelled back to the tank. The same thing happens when cranking, so just keep cranking for 15 seconds at a time until it fires and keeps running. I usually don't have problems but one time when I did not fill the filters enough, I did what he said and after a couple of tries, it worked fine. Who knew? Try it for a couple of times and see what happens.

 

[Rick486]

I changed both filters on my 4JH4E for 14 years and never once had a problem.
1. Before you do anything, shut the feed from the tank to the primary filter so fuel does not run out of the feed line
2. Remove the outgoing primary filter and install the new one. Fill the new one to the top with fresh clean fuel before installing.
3. Open the fuel feed to the tank.
4. Start the engine and let it run for 5 minutes or so.
5. Shut down the engine.
6. Close the feed from the tank once again.
7. Repeat the same procedure with the on engine filter.
8. Open the fuel feed.
9. Run the engine for another 5 minutes.
Voila! Finished. Never once had a problem.
Rick

 

[Tally Ho]

I used to do all that on my 4JH3E until a mechanic that I trust told me Yanmars don't need to be bled if you filled up the secondary filter. I was incredulous but his explanation was that normally the excess fuel that is not going into the cylinders goes back to the tank so if there are air bubbles they will quickly be expelled back to the tank. The same thing happens when cranking, so just keep cranking for 15 seconds at a time until it fires and keeps running. I usually don't have problems but one time when I did not fill the filters enough, I did what he said and after a couple of tries, it worked fine. Who knew? Try it for a couple of times and see what happens.

I agree. On my o,d 2GM20F, I turned the fuel valve off, removed the primary filter (an old Groco), refilled the housing with diesel. Then opened the secondary filter on the engine, filled the little housing with fuel. Opened the fuel valve and cranked her over…started righ up. Tied her up to the dock extra tight, put her in Gear and put a load on the engine…never faltered. Ran her out on the lake with no issues.

Greg

 

[bart]

I have the same boat and engine. Originally there was a primer pump located on the secondary filter which sometimes but not always leaked air. The yanmar repair was to change the top of the filter housing with a part that does not have a pump which is what you have. As there is no longer a priming pump you are supposed to loosen the outlet line hose clamp (there might be an arrow, I’m not near my boat) and crank the engine to get rid of the air.

 

[Digger54]

My Hunter 41AC has same engine. Since I have owned her, I always do just one filter at a time. Change primary (always filling the new filter to brim with fresh fuel) then run engine at 1500rpm for 10-15 min. Then change secondary in same manner. I do use the bleeder nut on top of filter housing and prime using the rocker arm on side of block. I do expect a short ‘stall’ when I first start up with advancing throttle to 1800rpm. Then next crank, she stays running just fine without having to bleed the injectors.

 

[dkinzer]

what you should do is bleed the injectors beginning with the first one. It should then fire after which the fuel flow will effectively bleed the remaining injector lines.

Spot on. Thanks.

I rigged up a makeshift remote start cable, loosened the injector line nut slightly at the #1 injector, cranked it over and it started up in a few seconds. As soon as I re-tightened the injector line nut the engine smoothed right out.

I ran the engine for about ten minutes, most of it under load at about 1800 RPM, and it ran perfectly.

Thanks to all who offered tips.

 

[jdrutten]

...
2. ... Fill the new one to the top with fresh clean fuel before installing.
...

I'll be swapping in new filters for the first time shortly after launch in (God willing) less than 3 months from now. The procedure seems pretty straightforward and I'm anxious to get to it, but is "fresh clean fuel" just fuel from the top of the tank? Should I reuse the fuel from the old filter to fill up the new filter? What's best practice on this?

 

[dkinzer]

is "fresh clean fuel" just fuel from the top of the tank?

I would think that you would want not only "fresh" fuel but filtered fuel as well. The fuel that comes out of my primary filter is filtered to 10 microns. I don't know what it is coming out of the secondary but it's surely filtered more finely than that.

It only took three or four minutes to fill up the primary filter using the built-in priming pump and probably twice as long to fill up the secondary filter using the manual lever on the lift pump.

In one of the YouTube videos I watched, the fellow highly recommended installing a bulb-type priming pump (like that in the attached photo) between the tank and the primary filter. I don't know if that would be faster but I suspect so.

 

[jeepbluetj]

I would think that you would want not only "fresh" fuel but filtered fuel as well. The fuel that comes out of my primary filter is filtered to 10 microns. I don't know what it is coming out of the secondary but it's surely filtered more finely than that.

It only took three or four minutes to fill up the primary filter using the built-in priming pump and probably twice as long to fill up the secondary filter using the manual lever on the lift pump.

In one of the YouTube videos I watched, the fellow highly recommended installing a bulb-type priming pump (like that in the attached photo) between the tank and the primary filter. I don't know if that would be faster but I suspect so.

View attachment 202437

I have the 3JH3E, but it's the same except for that missing cylinder. It only takes a few minutes to fill up the filters using the priming pump that's located next to the secondary filter. A JH series Yanmar will self-prime from there. Took a few tries to get it running and keep it running but it's easy.

The outboard priming bulb would certainly make it easier, but these are made for gas and I've seen so many go bad on runabouts there's no way I'd put one below on a sailboat. An electric pump in the return line with bypasses would be the best (and overkill IMHO, but it's a step towards a polisher)

 

[artboas]

I have the 3JH3E, but it's the same except for that missing cylinder. It only takes a few minutes to fill up the filters using the priming pump that's located next to the secondary filter. A JH series Yanmar will self-prime from there. Took a few tries to get it running and keep it running but it's easy.

The outboard priming bulb would certainly make it easier, but these are made for gas and I've seen so many go bad on runabouts there's no way I'd put one below on a sailboat. An electric pump in the return line with bypasses would be the best (and overkill IMHO, but it's a step towards a polisher)

I might draw attention to a post that I did a few months ago. It was how to change your fuel filter in minutes with zero fuel spill. It also shows a very easy way to pre-charge the filter with fuel.
I did this for both my engine and genset primary filters.
The issue is that the primary filters are located in hard to access places under bunks, and changing them is awkward. Also, you are now inevitably spilling fuel under a bunk, which takes forever to get the odour out,
I suggest reviewing this article