For the Yanmar experts.

rotrax

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We have an Island Packet SP Cruiser, a 12 metre motorsailer. It is fitted with a Yamar 4JH4 - HTE 110 HP Turbo Diesel, a 16 valve four cylinder engine. AFAIK the engine is a 2007 model, the year the boat was built. It had 257 hours only on the meter.

Upon taking delivery in 2016 it was difficult to judge the engine's performance as we had come from an aft cockpit yacht with a third of the HP. The amount of power available was awesome by comparison.

Everything fine for two seasons one we had got a few gremlins out of the way, including 600 litres of bugged fuel. Tommy Nielsons shipyard in Gloucester docks pumped that out and disposed of it.

We used 250 quids worth of filters moving from Gloucester Docks to Gosport where we are based. Since then no filter problems. The tank is almost 900 litres and the only access is through the fuel gauge sender hole. The black sediment that could not be removed was washed off during the trip and blocked the filters. Racor 500 primary, Yanmar secondary filter.
Both really clean and have been for three seasons. I never get anything from the Racor bowl or the Yanmar canister when I check by draining a little off.

Two years ago, slight issues with stalling when going between ahead and astern. Sometimes difficult to start after. I lifted the idle speed, some improvement to stalling, not to starting.

I am a fifty year small engine mechanic, experienced on 16,000 RPM motorcycle race engines to 500RPM antique semi diesels. I once made a piston for a Bollinders semi diesel by melting Hillman Minx bell housings for the alloy and casting in green sand using a paint tin as the mold.

Diesel experience is from BMC Black Cab engines, Peugeot and Merc car diesels plus my race truck and boat engines. This Yanmar is bugging me - terrible pun that - as it still exibits non starting imediatly after shutting down. I have checked and addressed the well known Yanmar relay issues, so no problem with proper cranking, voltage drop OK when cranking.

Yesterday, 1000 hour service completed, heat exchanger and intercooler serviced at home and refitted, filters and oil changed, new impeller, air intake filter cleaned, turbo removed, cleaned and repainted, bearings checked, no wear or end float, very free running. Exhaust elbow removed, checked and refitted.

Engine started fine, sounded good, responded to throttle perfectly, idle a shade high, but not stalling when ahead or astern engaged.

I allowed it to run against ahead at 1600 RPM's until it reached its working tempreture. Slightly lower since servicing the heat exchanger, 160 instead of the previous 175 degrees.

I hit the stop button, instant shutdown. I waited untill the oil pressure sensor made the alarm bleep, pressed start, no go. Ten attempts, still no start. Full gas in neutral, half gas, any combination, no start.

A half second squirt of ether spray, it roared away. Running to all intents and purposes as before. Went between ahead and astern at idle, no stall, so big improvement there. Ran it for another half hour in ahead, perfect.

Shut it down with the stop button, no start. Tried for a few minutes. Half second squirt, away she goes.

Last year we had exactly the same issue in Lymington. I left it alone. Next morning, instant start. This was tested several other times with the same result. Come alongside for the night, stop the donk using the stop button, no start. Following morning, away like normal. Why?

It uses perhaps half a litre of oil in 200 hours. It makes no smoke, black, white or blue. It sounds and runs great, valve clearances are spot on, only out of adjustment thing is raised idle speed. Without this it stops when manouvering between ahead and astern.

When it wont start after you have a problem!

As it will not restart sometimes when it has stopped while manouvering, so no stop solenoid involved, I tend to think it is not the stop solenoid causing the starting problem.

I have fitted a Facet type fuel pump between the Yanmar filter and the rotary injector pump. As there is no conventional lift pump fitted I assume it is internal inside the rotary injection pump. The Facet is a reccomended mod for poor starting. On our donk, no difference.

EP Barrus have been as much use as a chocolate teapot - could not deny or confirm about the lift pump. Suggested I asked a dealer!

I am tending towards one of the sensors somehow causing this non starting. It is fitted with a tempreture sensor, an oil pressure sensor and a sensor to detect water in the Yanmar secondary filter. Do they have the capability to stop the engine if low oil pressure, high tempreture or water in the fuel are detected? EP Barrus could not answer that either! Things have changed since I was on the end of the Technical Hotline at KMUK.

Any ideas?

I am wondering if I will ever fix it. I have rarely failed to fix stuff in the past, but I am begining to wonder about this one!

Any help gratefully recieved

PS - bearing in mind the cost of Yanmar bits, diagnosis by substitution is not the way I would like to go!
 
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I once made a piston for a Bollinders semi diesel by melting Hillman Minx bell housings for the alloy and casting in green sand using a paint tin as the mold.

Nice.

I made Lambretta piston ring pegs from a brass wood screw. Nicely tapered and tapped them in. Rode it from UK to Milan and back with those in.
 
How many hours has it now done?

I infer from your post this is exclusively a hot start problem? Correct?

Out of 100 hot start attempts what would the result be? I.E. is it every hot start?

What is the function of the relays you've attended to? What did you do?

Have you done cylinder leak down test or compression test?
 
Is there a wiring diagram that shows if the oil pressure and coolant temp have switches in them? Wjere do those switched wires go and what function do they perform?
 
not a yanmar expert, although pretty good at sorting out my 2GM generator engine, so you may just discard the following :-)

if it starts when spraying ether in the inlet, doesn't that mean there are no fancy relays cutting fuel?
Is it even possible to have a fuel cut off valve re-enabled when engine runs over x RPM? would need an ECU for that and it would be slightly confusing.
just wondering, no idea of this engine setup, nor it's ECU (if it has one!) and electronics!

sounds like an air in fuel line issue, but cannot really be if you just stop and try to start.
Could it be related to the el. lift pump?
how is this el.lift pump wired, when does it start working?
could it be that the pressure is "locking" smthg in the main pump?


V.
 
not a yanmar expert, although pretty good at sorting out my 2GM generator engine, so you may just discard the following :)

if it starts when spraying ether in the inlet, doesn't that mean there are no fancy relays cutting fuel?
Is it even possible to have a fuel cut off valve re-enabled when engine runs over x RPM? would need an ECU for that and it would be slightly confusing.
just wondering, no idea of this engine setup, nor it's ECU (if it has one!) and electronics!

sounds like an air in fuel line issue, but cannot really be if you just stop and try to start.
Could it be related to the el. lift pump?
how is this el.lift pump wired, when does it start working?
could it be that the pressure is "locking" smthg in the main pump?


V.

If I give it a half second squirt of ether it starts right up. I dont need to keep spraying, one tiny squirt and it lights right up. Runs perfectly normally untill stopped. It may start fine for ten starts, then fail to start. It gives full RPM under load, closes down normally to idle. It has run without missing a beat for 36 hours at cruising RPM, normally 2,200 RPM. Fuel consumption is good, certainly not excessive. It has 1023 hours, just had a major service. I need special kit to do a compression /leakage test but my experience leads me away from this as a problem. It runs too good when it is running. I am also very curious as to why, if I wait till the following day after a non start, it fires right up. It hardly seems to crank at all.

The fault is there with or without the Facet pump. This is wired to run all the time the ignition is switched on. It is low pressure, 5-7 psi IIRC. It sends excess around to spill return line back to the tank.

The online manual does not help much, not enough diagnostic info. EP Barrus technical guy did not want to know.

The facet pump also makes the pre injector pump bleeding easy and virtually unrequired. I have been through the filters, fuel lines and seals so many times I could do it blindfold.

Your third line is where I am starting to come from.

If it stops on engaging ahead or astern, it often will not start, no switching of the stop relay. If I stop it using the relay, still no start. I tend to think the stop relay is not the problem unless one of the three sensors, temp, oil pressure or water in the filter affects it.

This is the information I am searching for as the Importer cant - or wont - help.

Can any one on here?
 
Have you checked if the injectors re spraying when it is spinning but not starting ? Another thing you being a bike man ,,, on my Ducati there are two live feeds to the fuel pump , the first one primes the pump for starting then once started another one kicks in fed from the ( now charging ) alternator , without the first live feed the engine will spIn happily but not start , maybe something similar , you maybe familiar with that system .
 
two more ideas/things to consider:

if you want to discard the stop solenoid playing up and assuming it's a energize to stop, just disconnect it for a bit and try, must be a decompress or other way to turn off the engine, right? if its a energize to run I doubt it could be it. You could also wiggle it if its one of these visible lever/el.magnet things.

Could you try next time it fails to start, to undo a bit the banjo or whatever you have on the high pressure pump inlet, release a bit the fuel pressure (if any) and crank again? But then again unlikely to be the issue as it does it without the el.lift pump. Is the tank higher than the engine? Maybe worth temp fitting a pressure gauge there and monitor conditions whilst running, or stopping!

V.
 
Has the inj pump got a stop solenoid?
If so remove it and check for the presence of swarf.

Maybe engine heat effecting solenoid itself? pour some cold water over stop solenoid/inj pump then try a restart.
 
Hi Rotrax, Yanmar 4JH4-HTE is a completely mechanical engine as far as the running is concerned. There is no form of engine control unit, therefore no way of high temp, low oil pressure or low voltage interfering with the running of the engine. As with all diesels the key is 3 basic factors, enough compression to create the necessary temp to fire the atomised diesel, enough diesel correctly atomised and enough air and it will always start and run. You need to work out what exactly caused a running engine to stop. Go back to basics, did it run out of fuel, if yes why. If no it must have some external force causing it to stop. Because it will not start when hot then I suggest it has run out of fuel. That can be caused by air in the supply side, blockage in the supply side, possible blockage in the return pipes leading to lack of flow. There is an air filter on these engines but the air intake is so large I would not be looking in this direction.
You have discounted the stop solenoid, but this can be a source of uncommended engine stop, particularly if getting a spurious signal from the stop button at the panel. Solenoid is energised to stop. If you send me a pm with email ID I think I have a shop manual somewhere I may be able to send as a pdf.
Good luck.
Springer
 
Because of your recent fuel issues is it possible you have dirt(blockage) in the fuel line that is moving about in the lined depending on flow? It could be the low flow when at neutral that is causing this?
 
Has the inj pump got a stop solenoid?
If so remove it and check for the presence of swarf.

Maybe engine heat effecting solenoid itself? pour some cold water over stop solenoid/inj pump then try a restart.
Would seem some electrical component is overheating
 
When cranking hot but failjng to srart if you crack open an injector nut is it delivering fuel?

I reckon I might be using an optical tacho to check cranking speed cold and hot.
 
When cranking hot but failjng to srart if you crack open an injector nut is it delivering fuel?

I reckon I might be using an optical tacho to check cranking speed cold and hot.
I asked that same question , i guess they maybe sleeping down there just now ?
 
High pressure fuel from injectors when cranking.

The fuel issues were four years ago during our delivery trip. For the last three seasons, 200 hours each season, no fuel issues or dirty filters. The Racor looks like new when I change it annually. Never dirt or water in the bowl.

The engine never stops in use since I raised the idle 200 RPM. Moving from ahead to astern not much rev drop. If I stop the engine with the stop switch after running up to normal tempreture it often will not start, despite high pressure fuel at injector pipes. When it DID stall when engaging another gear, the stop solenoid was not operated, but still no start.

When it will not start - it ALMOST starts, but not quite - a half second squirt of ether spray lights it up. No amount of bleeding, low pressure or high pressure will achieve a start.

I am confident it is NOT air in the system. If it were it would exhibit the same symptoms the next morning, but it starts instantly.

Stop solenoid requires inlet manifold and other bits off to get to it in our installation, even disconnecting the wire requires the throttle control bracket to be removed.

It is not going to be easy. Engine tempreture appears to be a factor, but it feels cool to me. Since servicIng the heat exchanger, intercooler and fitting a new impeller the gauge shows 15 degrees less than before working against the springs in ahead at 1600 RPM.

Thanks for the replies, keep you ideas coming - I'm running out of them!
 
1. You need to work out what exactly caused a running engine to stop. NOW IDLE INCREASED, NOT AN ISSUE.

2. You have discounted the stop solenoid, but this can be a source of uncommended engine stop, particularly if getting a spurious signal from the stop button at the panel. Solenoid is energised to stop. THANKS, WILL LOOK IN THIS AREA.

If you send me a pm with email ID I think I have a shop manual somewhere I may be able to send as a pdf.
Good luck.
Springer


Thanks Springer, the non starting issue can occur with or without use of the stop solenoid. Now I have increased the idle speed 200 RPM - too fast in my opinion, but it keeps going when juggling the gears now - it still will not reliably restart after stopping it with the stop button.

I believed the engine sensors could not cause the engine to shut down but EP Barrus could not confirm that when I asked their technical guy that very question. Thanks for that, opend the thinking towards the stop button or solenoid.

Thanks for the offer of a manual, I have downloaded one but pretty light on the areas I need to understand.

The engine runs so well when it is going and starts so well even after months on the hard there is obviously nothing serious wrong with it.

She was on the hard from October 15th to June 12th. Started instantly, ran fine for an hour around the Harbour, up to normal working temp. then I stopped it with the stop button. No start, had to give it a half second blast of ether spray, lit up instantly. No further starting problems untill completing the 1000 hour service as we have been moving house and keeping sheltered because of our age.

Thanks for your input, appreciated.
 
Could it be time for an injector pump service?
If it starts instantly when cold then can't see it being a compression problem and even less so when hot.
 
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