mikuni heating problems

[Jacqmar]

Hi can anyone help please,

Our mikuni mx40 heating failed a few weeks ago and the warning lights suggested a new glow plug,sure enough the glowplug was burny out so we ordered a replacement.

Fitted this and heating was working and rads heated up.Left the boat for a week and when returned the heating was not working again.

[Jacqmar]

Hi

continuation of below!! oops!! pressed wrong button!!

the warning lights advised again glow plug problems so called Mikuni who advised probably needs de-coke. They can do this but the cost is c. £200 plus we will have to buy another glowplug!

Anyone know if it's possible to do the de-coke ourselves or is this a job for the experts?

Maybe it would be cheaper to get a heating engineer in?

Thanks

Martin

[Theo]

Hi

continuation of below!! oops!! pressed wrong button!!

the warning lights advised again glow plug problems so called Mikuni who advised probably needs de-coke. They can do this but the cost is c. £200 plus we will have to buy another glowplug!

Anyone know if it's possible to do the de-coke ourselves or is this a job for the experts?

Maybe it would be cheaper to get a heating engineer in?

Thanks

Martin

 

The glowplug is quite easy to take out but be careful with the insulating washers when you undo the wiring. Once it is out you will be able to see the fairly heavy guage wire heating element with the carbon sticking to it, mostly at the top. I use a wire bush to get rid of this but if that is not doing the trick it may well be possible to burn it off in a barbecue! (That's what I do with my Aga burner). Then refit it and see how you get on.

 

A new glowplug will cost you about £20 so it is a lot cheaper than the engineer. We keep a spare on the boat so that we can be cleaning one while using the other.

 

HTH

 

Nick

[DaveR]

The Mikuni is very voltage sensitive. Before I removed mine it was often the case that I had to start the engine to raise the voltage enough to ensure a start.

 

Sorry to be negative but on the Bensham (40 foot) there really wasn't a need for a central heating system. On red diesel I found that mine was more trouble than it was worth.

[Theo]

The Mikuni is very voltage sensitive. Before I removed mine it was often the case that I had to start the engine to raise the voltage enough to ensure a start.

 

Sorry to be negative but on the Bensham (40 foot) there really wasn't a need for a central heating system. On red diesel I found that mine was more trouble than it was worth.

 

 

Oh, NO!

 

I quite thought that I had merged the topics but on the computer that I am using at the moment most of the posts seem to have disappeared!

 

Sorry all :-(

 

Nick

[Tommo]

Hi can anyone help please,

Our mikuni mx40 heating failed a few weeks ago and the warning lights suggested a new glow plug,sure enough the glowplug was burny out so we ordered a replacement.

Fitted this and heating was working and rads heated up.Left the boat for a week and when returned the heating was not working again.

 

With the Mikuni it is absolutely vital that you clean out the boss, (that is the part that the glow plug screws into) there are tiny swirl holes in it that must be kept clean or the plug will carbon up in no time at all.

Take out the plug, turn off the fuel supply and disconnect the fuel pipe from the boss. Undo the 2 screws and pull out the boss from the unit, probably quite still due to the carbon. Make sure you don't lose the steel washer fitted round the boss. Clean off all the carbon from the wire gauze and carefully clean out the swirl holes with a small drill bit. Fit a new plug, you will also need a new gasket for the boss (Mikuni Part No 012058).

 

As for servicing the unit, it really depends on how hands on you are. I would say that if for instance you carry out engine maintenance then it should be well within your capability.

 

Ian

Edited March 29, 2007 by Tommo

[Theo]

With the Mikuni it is absolutely vital that you clean out the boss, (that is the part that the glow plug screws into) there are tiny swirl holes in it that must be kept clean or the plug will carbon up in no time at all.

Take out the plug, turn off the fuel supply and disconnect the fuel pipe from the boss. Undo the 2 screws and pull out the boss from the unit, probably quite still due to the carbon. Make sure you don't lose the steel washer fitted round the boss. Clean off all the carbon from the wire gauze and carefully clean out the swirl holes with a small drill bit. Fit a new plug, you will also need a new gasket for the boss (Mikuni Part No 012058).

 

As for servicing the unit, it really depends on how hands on you are. I would say that if for instance you carry out engine maintenance then it should be well within your capability.

 

Ian

 

What an incredibly useful reply, Ian. Thanks.

 

Nick

[Jacqmar]

Thanks for all your answers !

We will try your suggestion Ian. And Nick where do you get your glowplugs for £20?? The one we ordered from Nantwich chandlers was £39!

Thanks again

[GLYN FORSTER]

I had the same problem with a mikuni in one of my boats, i cleaned the glow plug boss as described by ian but it packed up again after a couple of weeks, i found it was contaminated fuel causing the problem, so i would reccomend checking your fuel to make sure you havent got water or the dreaded fuel bug in it, im not saying this is the definite cause just a suggestion..

 

The best place i found for parts was mikunis own shop the glow plugs are just over £20 and the glow plug boss is only £40 so maybe relace the boss instead of cleaning it, ive added a link to the website below.

 

http://www.mikuniheating.com/MX40mspare.asp

Edited March 30, 2007 by GLYN FORSTER

[Theo]

Thanks for all your answers !

We will try your suggestion Ian. And Nick where do you get your glowplugs for £20?? The one we ordered from Nantwich chandlers was £39!

Thanks again

 

 

I ordered mine direct from Mikuni. I hope that I am not misremembering the price.

 

Nick

[Jacqmar]

Thanks to all and our heating is now working!

Bought new glow plug and boss from Mikuni and will keep old boss for a spare.

Thanks again

Jackie

[Theo]

Thanks to all and our heating is now working!

Bought new glow plug and boss from Mikuni and will keep old boss for a spare.

Thanks again

Jackie

 

It just goes to show how very useful this forum is!

 

 

Nick