help with volvo md1

G

gavin400

Well-Known Member
Joined
25 Aug 2009
Messages
426
Visit site
My Volvo md1 is producing huge quantities of black soot when in gear and is not achieving full revs (doesn't appear to be the same problem when in neutral).

Initial thoughts were a fouled propellor or blocked exhaust elbow, however I disconnected the exhaust elbow and ran the engine and the black soot is emanating from the engine.

I'm not sure if the attached photos are clear:

Upon disconnecting the exhaust elbow it became clear that the one of the exhaust ports (bottom left of the photo) was completely blocked with some form of deposit

I drilled this blockage out so that the hole corresponded with the hole on the gasket

The questions are:

Is this blockage the cause of the black soot?

Should the remaining areas be cleared so that the apertures in the exhaust ports correspond with the apertures in the gasket/exhaust elbow?

If so, what is the best way of removing these deposits as they appear to be pretty hard?

All advice gratefully recieved

Gavin
 
Hi Gavin 400,
More knowledgeable folk will be along soon to advise you.
However it would seem logical that all deposits should be removed so as to have no step of significance between the head exhaust ports and the manifold corresponding ports.Before beginning to remove the carbon with a stout screwdriver or such, arrange to have the engine stopped at top dead centre on the compression stroke, to avoid getting debris down the cylinder.
A vacuum cleaner would be useful to clean away the loosened deposits.
Good luck with the dirty job!
 
Black soot means it's not burning fuel properly. May be caused by a lot of reasons. May be overloaded (too heavy propeller) or if the problem is a new one - injectors worn down. Or whatever. Some soot will normally be produced if there is a serious load or engine is too cold - this is nothing to worry about, but a deposit will form. Especially in cold exhaust.
But there may be a problem causing it. May be a faulty injector. Blocked air filter/intake. Wrong settings. Poor quality fuel. Low pressure, for instance valve not closing, so pressure inside too low. Glazed cylinders. Even worn down rings (oil is burned - this should show by bluish smoke). Or you name it...
IF (big if) engine is otherwise OK then it should be run at almost full load for some time, regularly, to get properly hot and burn all deposits. It's common among sailors to only run the engine for short time or only at idle really, no load, so everything inside gets filled with deposits...
MD1 is directly cooled IIRC - some 70'C max. It's in fact always running too cold. Maybe the thermostat is not maintaining high enough temperature?
 
Last edited:
gavin400 said:
Photo of gasket - i'm guessing the apertures in the exhaust port at the engine should replicate the gasket?
Click to expand...

Maybe but the same gasket fits other engines.

I know the MD11C better .. same gasket !

IIRC the roundhole is the water inlet, I forget which is which out of the others


Have you checked the tappet adjustments? Can you see the inlet valve stem via the air inlet ?
I guess it will smoke if the inlet valve is not opening properly or of the valve is so badly clagged that it restricts the air flow.

Problem if you have to take the head off! AFAIK head gaskets are NLA.
 
gavin400 said:
My Volvo md1 is producing huge quantities of black soot when in gear and is not achieving full revs (doesn't appear to be the same problem when in neutral).

Initial thoughts were a fouled propellor or blocked exhaust elbow, however I disconnected the exhaust elbow and ran the engine and the black soot is emanating from the engine.

I'm not sure if the attached photos are clear:

Upon disconnecting the exhaust elbow it became clear that the one of the exhaust ports (bottom left of the photo) was completely blocked with some form of deposit

I drilled this blockage out so that the hole corresponded with the hole on the gasket

The questions are:

Is this blockage the cause of the black soot?

Should the remaining areas be cleared so that the apertures in the exhaust ports correspond with the apertures in the gasket/exhaust elbow?

If so, what is the best way of removing these deposits as they appear to be pretty hard?

All advice gratefully recieved

Gavin
Click to expand...

It is not unusual for there to be a mismatch of apertures at the exhaust joint and certainly DO NOT drill where the drill is positioned.

One mistake many folk make is to install the exhaust joint the wrong way round and so block the exhaust port however this is not the case here as you valve black smoke with the manifold off

You either have an overload due to problems with the prop, the cold start is stuck in the start position allowing the fuel pump to over fuel. Another problem would arise if the max fuel screw inside the odd shaped cover on the back of the engine has loosened.

It is not unusual to get back smoke when trying to run a full revs with the boat tied up however the smoke should clear if the throttle is reduced and the engine slowed a little. Once underway the exhaust will stay clear.
 
The aperture where the drill is shown on the photos was completely blocked, and I drilled this out.

There is also a circular aperture to the top right of the photo - this was clear.

I'm guessing that both these apertures are ports for the cooling water.

The square aperture to the left hand side is, I think, for the exhaust gasses - this was also clear.

The cooling water is injected into the exhaust further down the line.

I checked the cold start device this morning and it was indeed jammed in the on position - I have now freed this.

Boat is out of the water so can't put the engine under load to check if its now ok.

I'm thinking about removing the injector and getting it serviced.
 
The cold start button you have checked should have a spring beneath it ,this may have become weakened or corroded. I used to always start my MD1B with this button depressed, which isthen released automatically by a mechanism (governor?) behind the small access panel.
Probably the cause of your problem, it is supposed to release when the revs of the engine speed up on starting. Would be prudent to have the injector checked and overhauled whilst out of the water,but read the handbook regarding the copper sleeve when drawing out and refitting the injector, these don't normally need renewing, but withdraw the injector carefully to prevent damage/leakage when replacing.

P.S I too think you were wrong to drill the extra hole unless there was a matching one in the exhaust elbow/block.


ianat182
 
Problem if you have to take the head off! AFAIK head gaskets are NLA.[/QUOTE]

Hi Vic ( I was chatting to you about SeaWyches) Head Gaskets can still be found. I boughta "decoke set" from "Keypart" a couple of years back,not cheap at £63 but beggars can't be choosers. I then Hydraulically Locked the engine by putting the exhaust manifold gasket on the wrong way round! Difficult to do but I managed it! I then found an American guy in Thailand (on ebay) who made them in copper at $35 well worth the money and posted quickly.
To the OP, if you are going to take the head off I will try to contact him if you want,PM me. Peter.
 
The cold start button delivers extra fuel for fast tickover at start up & should release when the throttle is opened past fast tickover. That on its own may have caused your sooty output due to excess fuel.

I assume you have had your injector checked & cleaned? It isn't expensive if you go to a specialist Truck place, they can also probably get you a new injector far cheaper than a Volvo Marine supplier!
 
ferrispeterchris said:
Problem if you have to take the head off! AFAIK head gaskets are NLA.
Click to expand...

Hi Vic ( I was chatting to you about SeaWyches) Head Gaskets can still be found. I boughta "decoke set" from "Keypart" a couple of years back,not cheap at £63 but beggars can't be choosers. I then Hydraulically Locked the engine by putting the exhaust manifold gasket on the wrong way round! Difficult to do but I managed it! I then found an American guy in Thailand (on ebay) who made them in copper at $35 well worth the money and posted quickly.
To the OP, if you are going to take the head off I will try to contact him if you want,PM me. Peter.[/QUOTE]

You're right it's included in the decoke set . Not listed separately though

10497_thmb.jpg
 
MD1 head gasket is different from MD1B. Different bore diameter. I couldn't source one either alone or as a set. Engineer in troon found one gathering dust under his bench, but nobody stocks them anymore.
 
halcyon23 said:
MD1 head gasket is different from MD1B. Different bore diameter. I couldn't source one either alone or as a set. Engineer in troon found one gathering dust under his bench, but nobody stocks them anymore.
Click to expand...

The picture in my post above is the decoke set, Part Ref: 876412 from Keyparts website http://www.keypart.com/volvo-penta/diesel-engine/md1/19581970.

Top left is the head gasket surely?


This is the set for the MD1B ( Part Ref: 876377)

10474_thmb.jpg
 
halcyon23 said:
MD1 head gasket is different from MD1B. Different bore diameter. I couldn't source one either alone or as a set. Engineer in troon found one gathering dust under his bench, but nobody stocks them anymore.
Click to expand...

Keep an eye on EBAY. The Fellow referred to elsewhere on here pops in from time to time selling the original style copper asbestos type which seem to perform better then the modern non resiliant types. They are shipped from Thailand. He does MD1 as well as MD1B
 
You must log in or register to reply here.

Share this page

Top