Mikuni MX40 problems
Gibbo
been the most reliable bit of kit on the boat.
Any experts here ?
First problem was about 8 months ago when it failed to light and tripped the 30
amp CB. This was traced to the glow plug being full of carbon. Rather than mess
around I replaced the glow plug, the gauze round it, the main wick and stripped
the unit and de-coked it..
Since then it has run for a total of probably around 750 hours on around 250
start ups (ie separate occasions)
The glow plug has now gone again. blocked full with carbon, the gauze around it
is damaged. If I have to replace these every 750 hours then I'll throw the
thing in the canal and replace it with something else. But what ?. It's a 10
minute job to replace these parts and wouldn't mind so much if the cost wasn't
Ł45.00 every time.
Is this normal ?
Could there be an installation problem ?
Any ideas ?
I know less about diesel heaters than I do about stamp collecting.
Gibbo - Nb Lionheart No 2
Niall
>
>Could there be an installation problem ?
>
>Any ideas ?
>
>I know less about diesel heaters than I do about stamp collecting.
>
Dunno about diesel heaters but we have a Propex gas fired blown air
heater in the motorcaravan which had a similar problem. Propex had to
replace the heat exchanger which was heavily carboned up. Possible
causes are lack of oomph from the fan due to low voltage or problems
with the combustion air intake / exhaust arrangements.
I rewired with heavier cables and improved the exhaust arrangements by
replacing the corrogated flexible tube provided with rigid tubing.
The original problem took a few years of use to manifest, although the
unit doesn't get much use as the camper is usually dismounted in the
winter months - not this year as we are going to the Boat Show and
Drascombe Assoc. AGM in January!
--
Niall
brian
"Niall" <nia...@btinternet.com> wrote in message
news:gVfSPwH3g+V=GV7JiScf...@4ax.com...
> On 06 Dec 2003 22:16:14 GMT, chrisgib...@aol.comma (Gibbo) wrote:
>
>
>
> >
> >Could there be an installation problem ?
> >
> replacing the corrogated flexible tube provided with rigid tubing.
> The original problem took a few years of use to manifest, although the
> unit doesn't get much use as the camper is usually dismounted in the
> winter months - not this year as we are going to the Boat Show and
> Drascombe Assoc. AGM in January!
>
Niall
No, I do realise that's not likely :-)
--
Niall
Neil Arlidge
> Lionheart came fitted with an MX40 which has caused one or two
> problems and not been the most reliable bit of kit on the boat.
>
> Any experts here ?
>
> First problem was about 8 months ago when it failed to light and
> tripped the 30 amp CB. This was traced to the glow plug being full of
> carbon. Rather than mess around I replaced the glow plug, the gauze
> round it, the main wick and stripped the unit and de-coked it..
>
> Since then it has run for a total of probably around 750 hours on
> around 250 start ups (ie separate occasions)
>
> The glow plug has now gone again. blocked full with carbon, the gauze
> around it is damaged. If I have to replace these every 750 hours then
> I'll throw the thing in the canal and replace it with something else.
> But what ?. It's a 10 minute job to replace these parts and wouldn't
>
> Is this normal ?
>
> Could there be an installation problem ?
>
> Any ideas ?
After I re-worked my Mikuni instalation it has run OK for the last 3
years................but then I hardly use it and has done no where near 750
hours!
After a complete de-coke (I found that the Mikumi came to bits really
easily) I put down the problems to the exhaust. This was re-positioned just
below the gunwale (so protected from being blocked off when mooring, by the
cant of my hull sides) I also used a different tank fitting for the exhaust,
that I reamed out to stop the restriction present on the old fitting. Since
it was sorted, my Mikuni exhaust runs clear apart from start up and cool
down.
--
Neil Arlidge - NB Earnest
Follow the travels of the TNC at http://www.tuesdaynightclub.co.uk
Roger Millin
> Lionheart came fitted with an MX40 which has caused one or two problems and not
> been the most reliable bit of kit on the boat.
>
> Any experts here ?
>
> First problem was about 8 months ago when it failed to light and tripped the 30
> amp CB. This was traced to the glow plug being full of carbon. Rather than mess
> around I replaced the glow plug, the gauze round it, the main wick and stripped
> the unit and de-coked it..
>
> Since then it has run for a total of probably around 750 hours on around 250
> start ups (ie separate occasions)
>
> The glow plug has now gone again. blocked full with carbon, the gauze around it
> is damaged. If I have to replace these every 750 hours then I'll throw the
> thing in the canal and replace it with something else. But what ?. It's a 10
> minute job to replace these parts and wouldn't mind so much if the cost wasn't
>
> Is this normal ?
>
> Could there be an installation problem ?
>
> Any ideas ?
>
> I know less about diesel heaters than I do about stamp collecting.
The instructions recommend an annual (I think) decoke service and then
every second time a more thorough service. As the difference between
the two is virtually nil except for a slightly more complete strip
down and a more comprehensive gasket kit I do the larger service every
time. I have never had the glow plug carboned up in two years of use
and the unit has been totally reliable. It has been sensitive to air
in the system and has shut down because of overheat, but once bled
seems OK. The flashing diagnostic light tells you what is wrong and
it's just a matter of bleeding the heat exchanger.
I spoke to Mikuni about an apparent hole in the gauze opposite the
glow plug and they said that there was no need to worry unless the
hole was completely through the gauze (it comprises several fine
layers). As I had already bought the gauze I replaced it anyway. Other
than these thoughts I cannot really think why yours is carboning up so
badly except maybe fuel quality (or just maybe I can put a lower
voltage to the glow plug scenario that might fit, but you're ideally
suited to checking that one ;-)). In the vehicle application the
instructions show a small in-line filter in the fuel line but for
boats, with the no plastic component rule) mine is plumbed in without,
using a supply direct from the main underfloor fuel tank.
Sorry can't be more help than this but, honestly, mine has been
absolutely reliable and because I live on the boat part time it gets
more use than some, I guess.
Roger.
Gibbo
Yeah it would be embarrassing if the cabling was to small. But it isn't.
The exhaust is short and straight and exits just below the gunwale. Always has
clear air.
Air intake is direct to the air pump and is clear. Getting good voltage to the
air motor (and it's spinning at what *sounds* like normal speeds).
Martin it's probably in your best interest if I *don't* get this cured as I
will happily throw it in your direction :)
Paul
"Gibbo" <chrisgib...@aol.comma> wrote in message
news:20031206171614...@mb-m05.aol.com...
> Lionheart came fitted with an MX40 which has caused one or two problems
and not
> been the most reliable bit of kit on the boat.
>
> Any experts here ?
>
> First problem was about 8 months ago when it failed to light and tripped
the 30
> amp CB. This was traced to the glow plug being full of carbon. Rather than
mess
> around I replaced the glow plug, the gauze round it, the main wick and
stripped
> the unit and de-coked it..
>
> Since then it has run for a total of probably around 750 hours on around
250
> start ups (ie separate occasions)
>
> The glow plug has now gone again. blocked full with carbon, the gauze
around it
> is damaged. If I have to replace these every 750 hours then I'll throw the
> thing in the canal and replace it with something else. But what ?. It's a
10
> minute job to replace these parts and wouldn't mind so much if the cost
wasn't
>
> Is this normal ?
>
> Could there be an installation problem ?
>
> Any ideas ?
>
some feedback about his products, { as I have no central heating atm} When I
asked him regarding service schedules etc. He was telling me about the
intervals of which I cant remember the exact time in between, but he did say
he had just serviced a `coked up` heater which wasnt very old and of which
he put down to not using the fuel additive in the diesel. { fuelset }.
Regards Paul