Mikuni issue in newly acquired boat

[chilligibbon]

Hi, I have just become the very proud new owner of a Steve hudson boat. It is 13 years old and still has the same Mikuni mx40 that was fitted as new. Started fine this morning and ran for about 20 mins, rad got warm and then it cut out. Checked thermostat and was set above temp in cabin so that was not the culprit. Did a re start, again fired up ok but cut out after about 10 mins. Any ideas any one, any help very much appreciated as could do with hot water in the near future!

[mrsmelly]

Hi, I have just become the very proud new owner of a Steve hudson boat. It is 13 years old and still has the same Mikuni mx40 that was fitted as new. Started fine this morning and ran for about 20 mins, rad got warm and then it cut out. Checked thermostat and was set above temp in cabin so that was not the culprit. Did a re start, again fired up ok but cut out after about 10 mins. Any ideas any one, any help very much appreciated as could do with hot water in the near future!

Hi

 

My last boat was a Steve Hudson when I was a narrowboater, damn good boats. As for the Mikuni if original then its getting a bit long in the tooth. My suggestion would be to take it of and send it direct to Mikuni they are a brill outfit that will sort it out by return of post. Ring them first they are first class 02380528777

 

Tim

[NMEA]

Hi, I have just become the very proud new owner of a Steve hudson boat. It is 13 years old and still has the same Mikuni mx40 that was fitted as new. Started fine this morning and ran for about 20 mins, rad got warm and then it cut out. Checked thermostat and was set above temp in cabin so that was not the culprit. Did a re start, again fired up ok but cut out after about 10 mins. Any ideas any one, any help very much appreciated as could do with hot water in the near future!

Could be an overheat (or thinks it is) or a sensor fault, check there is no air in the system, have a look and see if any flashes from the Control box L.E.D. If you would like a copy of the workshop manual just let me have your email address by P.M. Also check the boat's service log to see when the MX was last serviced.

[Doorman]

Hi,

 

Have you checked the Led indicator on the electronic control unit? If the heater fails to run as you describe there's a set of lights on the rectangular control unit and they indicate what the problem could be. They flash on and off for a given number of times depending what the fault could be.

 

If the heater is situated where Steve normally installs them, depending on whether you have a modern engine or vintage option, you can lift the port side access board and view the control unit from there. Count the amount of times the lights flash before pausing, then if the writing on the front of the control unit is still clear, you will see a ledger that illustrates what the fault is according to the lights.

 

You can download various manuals from the Mikuni web site that relate to the MX40 heater, together with assembly drawings and lists of parts.

 

Hope this helps,

 

Mike

[NMEA]

You can download various manuals from the Mikuni web site that relate to the MX40 heater, together with assembly drawings and lists of parts.

 

Hope this helps,

 

Mike

One can not download any manuals from Mikuni, only a fault flow chart and parts list.

[mrsmelly]

Hi

 

If you need manuals they are easily obtained. We have copies at work if you need them. The unit is an absolute doddle to remove in a few minutes especialy if Steve fitted it. They are easy as pie to service but if like me you cannot be bothered the guys at Mikuni will give you free advice on the fone or sort it out for you very quickly at very reasonable rates.

 

Tim

[Timleech]

A minor hijack here. I have an MX40 which came from a fire damaged boat, no controller, will an MX60CFD controller work with it, at least sufficient to check whether the heater works?

I have no use for the heater, just want to check that it works & then offer it for sale.

 

Tim

[NMEA]

A minor hijack here. I have an MX40 which came from a fire damaged boat, no controller, will an MX60CFD controller work with it, at least sufficient to check whether the heater works?

I have no use for the heater, just want to check that it works & then offer it for sale.

 

Tim

No, I have known good used ones if any help.

They are easy as pie to service but if like me you cannot be bothered the guys at Mikuni will give you free advice on the fone or sort it out for you very quickly at very reasonable rates.

 

Tim

They as easy as pie to service if you have the kit including exhaust flue anyliser, if not, they are as easy as pie to get working again.

[Doorman]

Hi

 

My suggestion would be to take it of and send it direct to Mikuni they are a brill outfit that will sort it out by return of post. Ring them first they are first class 02380528777

 

Tim

I'm afraid that my experience of Mikuni service efficiency doesn't really concur. Given that the manual advises to send the Air Motor Assembly back to Mikuni should it fail and not to attempt to service it yourself, I sent it off to their depot in a packing box whereby after a week it was returned in a Jiffy bag. Two of the blades on the plastic impeller were broken off due to clumsy post handling so they sent another a few days later, once again in a Jiffy bag. Totally inadequate packaging material considering the fragility of the blades.

 

After just 8 hours of service, the motor failed again. This time, I stripped it down only to find that the commutator was clogged with carbon deposits and the whole assembly required cleaning thoroughly. It was clear from the condition of the motor that the Mikuni staff had only blasted a whiff of compressed air through the intake port then returned it (in the Jiffy bag).

 

Following a thorough cleaning of the commutator and reassembly of the motor it now works fine, although removing the plastic cowl involves some patience and enough money for the swear box! Another potential problem is that although the assembly has a 12 volt sticker placed upon it, according to the Mikuni people it is in fact a 9 volt motor, so be careful when bench testing.

 

One can not download any manuals from Mikuni, only a fault flow chart and parts list.

I beg to differ.

 

I downloaded an installation manual from their site a couple of years ago. The service manual though was kindly emailed to me from one of their admin staff. Can not fault that side of their operation.

 

ETA just checked their site again and you are quite right, as you say, they now only offer a limited amount of information for download.

Edited November 3, 2013 by Doorman

[NMEA]

 

I beg to differ.

 

I downloaded an installation manual from their site a couple of years ago. The service manual though was kindly emailed to me from one of their admin staff. Can not fault that side of their operation.

Beg all you like, you still can not download any manuals from the site, that is easy to confirm by trying, two years ago is not now, Like me, Steve is happy to email you one but you can not download them from the site.

[nicknorman]

Hi, I have just become the very proud new owner of a Steve hudson boat. It is 13 years old and still has the same Mikuni mx40 that was fitted as new. Started fine this morning and ran for about 20 mins, rad got warm and then it cut out. Checked thermostat and was set above temp in cabin so that was not the culprit. Did a re start, again fired up ok but cut out after about 10 mins. Any ideas any one, any help very much appreciated as could do with hot water in the near future!

Welcome to the Hudson club! Hope you enjoy your's as much as we do our's.

 

As has been said, the diagnostic led in the control box should indicate why its shut down. 9 flashes is overheat failure, 8 flashes is voltage out of correct range. These are probably the two most likely ones as the other failures are likely be detected at or before startup.

 

Just a word of advice on the use of the thermostat for when you get it going properly - Mikunis hate nothing more than short cycling, ie starting up and shutting down repeatedly due to the cabin temperature being around the value set on the stat. I recommend that when you have the Mikuni on, you ensure the temperature on the stat is set very high, then if it gets too hot in the cabin, manually shut it off. Really, you want to try to have a minimum on time of an hour or so.

Edited November 3, 2013 by nicknorman

[Doorman]

Beg all you like, you still can not download any manuals from the site, that is easy to confirm by trying, two years ago is not now, Like me, Steve is happy to email you one but you can not download them from the site.

I take it from the nature of this reply, you hadn't noticed my edited acceptance of your original comment, not to worry, we all make mistakes!

Edited November 3, 2013 by Doorman

[MtB]

Hi, I have just become the very proud new owner of a Steve hudson boat. It is 13 years old and still has the same Mikuni mx40 that was fitted as new. Started fine this morning and ran for about 20 mins, rad got warm and then it cut out. Checked thermostat and was set above temp in cabin so that was not the culprit. Did a re start, again fired up ok but cut out after about 10 mins. Any ideas any one, any help very much appreciated as could do with hot water in the near future!

 

Sounds to me as though the circulagting pump is not operating. Is it a separate component or part of the Mikuni?

 

MtB

[Biggles]

I had several problems with my MX60 in the short time I had it.

 

1. There is a tiny filter in the electronic fuel cut off if you have one fitted. This is easily serviceable but not many people know its there.

 

2. The wicks eventually burn out. These are easy to replace but do require some filing to get a perfect fit.

 

3. Check the optical sensor is clean.

 

4. Maybe just a general decoke is all that's needed.

 

When mine was running it was just fine.

[nicknorman]

Sounds to me as though the circulagting pump is not operating. Is it a separate component or part of the Mikuni?

 

MtB

I think its unlikely it would burn for 10 mins and warm the rads if the pump was not operating. However the pump may be weak for some reason, or the flow blocked. The pump is integral to the unit and checked by the microprocessor at startup, though whether it can detect its actually rotating as opposed to just having electrical continuity I don't know.

[chilligibbon]

Hi All

 

Many thanks for all of the information, I know the led on the control panel was flashing so will fire it up again at the weekend (unless I manage to sneak down to the boat before then!) and see if I can determine the fault code.

Will keep you all posted and I'm sure will be back when diagnosed and moving onto the next step!

[nicknorman]

When you are on the boat, check there is coolant visible in the header tank. You don't want to have too much in there else it will overflow when it gets got, but a couple of inches in the bottom when its cold at least. If there is no fluid in there, it may be drawing in air causing an overheat shutdown. If you need to add fluid, add premixed antifreeze / water with say 25% antifreeze, making sure its the same type of antifreeze as is already in there (green or blue is one sort, red or orange is another sort). They don't like to be mixed.

[Doorman]

Hi

 

If you need manuals they are easily obtained. We have copies at work if you need them. The unit is an absolute doddle to remove in a few minutes especialy if Steve fitted it.

 

Tim

 

It's even easier to service, or even get working again, by fitting a two way snap connector to the Air Supply Assembly cable which enables quick disconnection, without having to enter the upper cover of the heater and fiddle with the waterproof coupler. Once this has been done, disassembly of the main combustion chamber assembly can be affected without the need to remove the heater from the vessel.

 

Should the heater require overhauling, whereby special tools are required to test the exhaust gases for C02 emissions etc., then I would recommend removing the complete heater and sending it off to a specialist dealer, or even Mikuni, providing that they've exhausted their supply of Jiffy bags. Either way, a detailed service manual should be acquired before carrying out any remedial work.

[adrianh]

What state are your batteries in, my MX 40 will shutdown if the battery voltage gets to low. It also will not start at less than approx. 11.8 volts or if the control box/wiring get damp from condensation - its in a damp engine compartment.

The initial glow plug start up draws a heavy current, running current is not to high but you still need good batteries for continuous running unless you have hook up or run the engine regularly.

[nicknorman]

It's a Hudson, it won't have a damp engine compartment!

 

If it is the battery state, the flashing LED will tell us. But you are right, the Mikuni type heater is not a very good full time heater if off grid since the current drain is significant over long periods. We use ours for the odd few hours, to warm the boat before arriving (and then lighting the stove) or to give a burst of heat on those cool spring and autumn mornings and evenings when it isn't really cold enough to justify having the stove on all day.

[Doorman]

A tip to assist in the removal of the heater, should ever you need to do this, would be to replace the rubber coolant hoses that connect it to the main heating circuit with silicon alternatives. Not only do these last longer, but also make the removal of the unit much easier.

[Redeye]

Hi

 

I used to have a Hudson with a Mikuni, have you checked the fuel filter? Mine exhibited similar problems and I traced it down to the filter. It ran for a short period then lost the flaame through fuel starvation, fuel would then slowly flow through allowing the burner to re-start. I think Hudson uses a small lister type filter. It will of course be an absolute pain to get fuel back through if you change the filter.

 

Cheers

 

Redeye

[Doorman]

Hi

 

It will of course be an absolute pain to get fuel back through if you change the filter.

 

Cheers

 

Redeye

Not necessarily Redeye.

 

If you fit a 'T' connection to the fuel line close to the pump on the suction side and have a short length of fuel pipe extending from the spare leg with a female connection and compression olive, you can attach a bleed device via a 6mm ID section of fuel hose fitted over the olive. With this set-up you can bleed fuel from the tank via the new filter right up to the pump.

 

Once this has been achieved, simply screw a male blanking connection to the spare leg on the 'T' connection to seal it up and away you go. Simples. If I ever get chance to return to the boat from our house I'll post a photo of this arrangement that I have on our Mikuni, all will be clear then.

 

Mike

[chilligibbon]

Hi all,

 

Made it back to the boat tonight and fired up the Mikuni whilst running the genny so could rule out a power issue..

Again ran for about 20-30 minutes heated the rads nicely then stopped.

Have a flashing led on the switch, 3 long flashes followed by 6 short ones, does anyone know what this error code is telling me?

 

Also need to replace all 4 leisure batteries as they had lost most of the charge while standing this week, anyone know of any good internet offers at the moment?

 

Thanks

 

Chris

[nicknorman]

The LED on the switch isn't the one we were talking about, that one is inside the black oblong metal box of electronics mounted on the side of the heater. You can remove the lid by undoing 1 screw.

 

It's a guess, but maybe the switch led mirrors the one inside with the short flashes. Someone else will hopefully be along soon to confirm that. In the mean time, why not remove the cover on the box and check the number of flashes on the internal LED. 6 flashes is fuel pump failure.

 

Presumably it knows this due to no electrical continuity, might be worth checking the wiring to the pump (the pump is separate from the body of the Mikuni, in the fuel line just before it goes into the Mikuni. Quite small.) Alternatively I suppose it might work that out due to the flame going out with no other cause, in which case a fuel blockage, as mentioned before, might be the issue, eg the filter blocked. Have a think about how you are going to re-prime the fuel lines and filter before you dismantle the filter!

Edited November 8, 2013 by nicknorman