Author Topic: Throttle lag on Hylas 54 4JH3-DTE  (Read 4042 times)

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Midnight Mile

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #19 on: September 06, 2019, 04:11:33 PM »
I thought I'd add to this in case anyone comes across it in the future. We bought hull #28 last year (the previous owner has entries in this thread about the issue) and experienced the same symptoms described by others here. After running for a while, when shifting from neutral to reverse or forward, the throttle would take several seconds to respond (and sometimes not at all). The engine ran great and cruising RPM, never ran hot, I changed all the filters, inspected the injectors, etc. The one difference that I experienced that I didn't see here was leaking fuel return lines on the cylinder head.

It didn't sit right in my mind that this problem would only occur when the engine had been running for a while since it never ran hot, had plenty of air and fuel. The VE type is a mechanically driven pump and I didn't see how temperature or running time would effect it. However, out of ideas, I had a mechanic out to pull the injection pump for a rebuild. It occurred to me that since the return system kept leaking, we should check for blockage. He tried to blow air through the return line that runs from the injection pump to the return manifold and there was significant back-pressure. I told him thanks for coming out and I would check the return system first before removing the pump (estimated $1400-2800 to rebuild including labor). The next day I blew air through the line until it flowed freely back to the tank, checked and cleaned the manifolds, etc. The lag problem has not occurred again (yet).

I've tested it now for a few weeks and this appears to be a major contributor to the issue (if not the entire problem). The overflow valve in the VE type injector pump "functions to maintain a constant fuel oil temperature in the injection pump by returning excess fuel oil to the tank" (from the manual). My thinking is that if there is a blockage in the return system, it is unable to return enough hot diesel back to the tank after the engine heats up. This in turn won't allow enough fresh fuel from the tank and the engine cannot rev under load. Unfortunately, I can't say with 100% confidence that this is our problem but I will report back in a few weeks.

Long story short, if you are experiencing the throttle lag issue, check your return system (to all tanks) first. I'd also recommend checking the tank venting system too. A vacuum on a tank might cause similar symptoms.

Hopefully this helps someone.

Dan
S/V Midnight Mile


tulsag

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #18 on: August 07, 2019, 09:24:19 PM »
Final update.

If you recall, nothing worked and we tried everything, including sending the injection pump to Bosch in Germany for review.  Bosch sent it back and said it was fine.  Last year the throttle lag happened only rarely and I thought the problem was solving itself.  This year we start off from Sicily and literally 50% of the time the throttle had extreme lag or never went faster than idle forward or reverse for minutes before leaping to proper rpm's for a high throttle position.  We limped up to Olbia, Sardina and I just decided to order a new injection pump without hiring another mechanic to run his traps and scratch his head.  IT HAS WORKED GREAT for a month now!!!  Feels like a new engine.  I wish I had done this in Croatia two years ago but the mechanic insisted that it was NOT the injection pump!!!

Mark
sv TARA
Mark Powell
Hylas 54  hull#33  TARA

Knoxan

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #17 on: October 02, 2017, 02:27:58 PM »
Steve
Unfortunately I couldn't find an animation. It would have made things so much simpler to understand. I don't see a way to adjust the governor. At most there may be an idle speed adjustment screw but in the case of the UTE version  of the governor there doesn't even seem to be such a thing.
I was talking a couple of days ago with a neighbor who is a former commercial marine and superyacht engineer who has opened a local engineering workshop. When I mentioned the throttle lag issue he immediately said it would be the governor weights or sleeve sticking on some dirt or the sleeve spindle needs polishing.  His advice is that if you have the pump serviced or rebuilt it is an area you should ask the workshop to focus on.
As to removing the governor without removing the whole injection pump, I presently have my engine 4JH2-TE completely accessible in the back of my pickup (long story) and it doesn't look feasible. Looks best to remove the whole pump and then split the governor, but I am not sure how simple it is to remove the injection pump drive gear.

Andy

Andy

steve herlong

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #16 on: September 25, 2017, 03:28:42 PM »
Andy,

I have been dealing with Throttle Lag and also with Clutch Judder (who knew this was such a thing) on board Rise 4JH2-UTE since I've owned her for the last 5 years.  The issues seemed worse this season but it comes and goes.  I do have a Max Prop as well and the prop/clutch combination does seem to cause the problem. The Clutch Judder can happen whenever I am shifting very frequently getting into a slip. What a racket it makes but shifting quickly in and out of gear stops it.  Thanks for your "simplified View" of the Throttle Lag issue too!  It is an excellent description of the issues that are going on and I agree it is anything but simple.  In your research did you find any graphic links to help us "see" what might be happening at the injection pump and the governor?  I see an earlier comment on this thread from Burt that suggests that an adjustment to the governor may be all that is needed. Can the governor be adjusted without pulling the injection pump?

Steve
H49-28 Rise

Knoxan

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #15 on: September 25, 2017, 08:12:59 AM »
I also had incidence of clutch judder. It happened frequently a couple of years ago when there were issues with throttle lag. Both problems rarely occur now but not confident that situation will last.
I believe the theory of harmonic effect between maxprop and governor has a lot of merit. The clutch is essentialy a simple piece of equipment and it is hard to imagine it causing judder on its own particularly when the load end has an ideal fluid coupling ie the sea. It would be good to know if anyone else has/had this issue and what type of prop was installed.

Andy
True Brew H46#32

Andrew

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #14 on: September 24, 2017, 09:00:02 PM »
Hi there,
Not sure if my issue was the same cause or not - when I bought my hylas 51 I fitted a max prop and had a major engine service - and there was no drive in forward or reverse, and revs would not increase as the throttle was increased - just increasing vibration.  The mechanic decided it was the gearbox, and fitted a new cone clutch and gear set, which seemed to fix it. Most of the time gears changed and revs increased smoothly.  But occasionally, when the engine was hot, it would do the same again - engage gear and revs would not increase with throttle increase, just lots of vibration.
I met a charter fleet mechanic in the BVI who said it was a common problem with yanmar with cone clutch gearboxes.  He thought that some kind of harmonic was set up when clutch judder caused the inhjector pump or governor to cycle on and off, and that this was made worse by the max prop blades bouncing off their limits with the judder. I put up with it for years, not getting better or worse, but always stressing me out in marinas- and eventually bought a brand new gearbox - which totally cured the problem.  Not sure if this is related to your problem, but who knows?
Andrew Eaglen (Hylas 51 "Hanne Danske")

tulsag

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #13 on: September 24, 2017, 07:21:39 PM »
Wow! Andy, your self-described 'simplified view' is anything but simple. That all makes great sense. I had mentioned the governor was of particular concern as the mechanic from Croatia sent off the injection pump, but I don't know if it translated very well and if the Bosch fellows took any particular attention to it.  The bad news for the 4JH3-DTE is that I was told they don't make the injection pumps anymore so refurbishing is the only option. 

Mark
Mark Powell
Hylas 54  hull#33  TARA

Knoxan

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #12 on: September 24, 2017, 11:13:48 AM »
Having experienced this issue a couple of years back and having my engine presently out while hull repairs are being carried out in the engine bay I have been considering replacing the injection pump. as well as a few other components. However, before going that expense I have tried giving thought to what may be the root cause of the issue.
Looking at the drawings and reading up on fuel injection systems my simplified view of its operation is that the throttle lever directly moves the rack which adjusts the plunger geometry and hence fuel flow. It either works or doesn't . The fact that the engine does normally change speed when asked to do so implies that so far this works. The throttle setting also positions a lever to give a speed reference position for the governor, however, more of this later. The fuel rack movement is modified by two other mechanisms. Firstly, the rack stroke is extended by the boost compensator which increases fuel flow when the turbo cuts in. This works by sensing increased inlet manifold pressure through a diaphram  which tends to push the rack forward for higher fuel flow. Secondly, the speed governor centrifugal weights move a spring loaded sleeve on the camshaft to modify the rack position in relation to the set speed position set by the throttle lever. It is a complicated setup which is hard to visualise.
In my mind the problem of not getting reliable acceleration particulary from idle is most likely to be associated with the governor. It seems to be the only component which can hold back the rack to a low fuel flow position. The sleeve may be occasionaly binding on the shaft coupled with a weak return spring and is tricking the pump into thinking the revs are already up.
I know many have had the injection pump serviced and I assume this would include the governor components and polishing the camshaft. I have decided I will go down the road of a new pump rather than a refurbished one since I really don't trust what comes back from some workshops.

Andy
True Brew
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Berkeley East

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #11 on: September 23, 2017, 09:23:44 AM »
Mark

Thanks for the update.

Berkeley East has a very similar problem, no throttle response. Started out infrequently and now it happens every time we have run the engine for over an hour. Tried to have it diagnosed in Sicily, with no success, but have developed a work around. We stop and let the engine cool for 15 - 30 mins before entering a marina. We also take the starboard engine doors off for the last hour of motoring. No idea why this works, but it does. I'm guessing it is temperature related.  Docking with only idle speed was just to exciting for us.

Larry


tulsag

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #10 on: September 23, 2017, 06:32:08 AM »
Update:

Well, we tried everything: new injectors, direct fuel tank, valve adjustment, filter changes, reset the timing, blah, blah , blah!  Spent 10 days in Split, Croatia Marina and with no other options, we had the fuel injection pump sent to Yanmar (Bosch actually, because I was told they make them for Yanmar). We spent a total of $4,000 chasing every conceivable solution. After re-installing the injection pump, we took Tara out for a test sail (motor) and she performed perfectly. High fives all around.  One hour later we throw the lines to resume our summer and would you believe, no acceleration! We decided to carry on south simply because we had no further ideas. For about 2 days, we had a decreasing number of occurrences until finally the problem seems to have just gone away completely.  In the two months since,  we have made it to the east end of Greece and things appear to be fine now.

After consulting with experts, forum users, and even the Oracle from Delphi, my advice if the throttle lag starts to happen to you is bear with it as long as possible (and enter marinas VERY carefully because idle forward and reverse may be all that you get!) and most of the time the problem disappears. If it does not, send the injection pump in for a rebuild as a last resort. Maybe the rebuild was the right solution to our problem but strangely, it still needed a few days to go away. Bizarre!

Mark
« Last Edit: September 23, 2017, 11:33:40 AM by tulsag »
Mark Powell
Hylas 54  hull#33  TARA

steve herlong

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #9 on: July 20, 2017, 06:17:49 PM »
I have had the same issue with my 4JH2-UTE for the last 5 years!  As someone else mentioned, the problem comes and goes but I never know if I will have any rpms when maneuvering in a marina.  I am so surprised that this seems to be a common problem across different engines.  Do they all share a common injection pump?   Thanks to you guys I now know what the fix likely is.

Steve

H49-23 RISE

nightflight

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #8 on: July 10, 2017, 12:57:49 PM »
Same problem on JH3TE.  I have an autoprop too.  Got worse and a injector pump was diagnosed and rebuilt at 3000 hours (2011).  Problem was solved and still working well at 6000 hours.
Michael
Michael & Ann McDougall
S/V Nightflight
Michael@nightflight.us
mssi:367064630

brian black

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #7 on: July 08, 2017, 11:47:58 AM »
same for us on our 46.  we had the injector pump and injectors removed, rebuilt and replaced.  solved the problem

Knoxan

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #6 on: July 08, 2017, 07:05:44 AM »
I had a similar problem a couple of years ago with a 4JH2-te  on my H46. Didn't happen all the time but often enough to make me nervous about leaving dock or casting off a mooring. Never knew what would happen. However, after a winter ashore problem dissapeared and has so far not returned.
I suspected that the problem might be the maxprop propeller being sluggish in adjusting blade position and causing too much load on the engine when accelerating from rest. The improvement came after a complete change of lubricating grease in the propeller. May have been co-oincidence but have now had two seasons where the issue has not returned. Keeping my fingers crossed.

Andy
H46-32 True Brew

burtpreston

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Re: Throttle lag on Hylas 54 4JH3-DTE
« Reply #5 on: July 08, 2017, 03:07:30 AM »
A friend had a similar problem with his engine. I believe it was caused by an improperly functioning governor. He consulted many "experts" and paid lots of money before getting it fixed, which was a simple adjustment. It may be an area to explore.

Burt Preston
Exuberant H-44

 

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