Help needed - Volvo MD1 B question.

[Jenko]

Greetings,

We have a Volvo MD1 B on our Westerly Pagent. At the moment, there are a few problems.......
1). The engine takes a long time to fire up when cold.
2). It will only push the boat along at 3knots. It just does not seem to rev, and occasionally just
cuts out for no apparent reason.

When we bought the boat 4 months ago, she would do 5 knots under engine. But on Sunday, it only just got us
out of the river hamble.
Any suggestions would be much appreciated.


Thanks.

Paul.

 

[Guest]

Hi Paul, The MD1B is an elderly motor, but if it was pushing you along adequately just four months ago, it could well be fuel related.

Drain your water trap first. If you get a lot of H2O then try the engine and see if that has helped. Changing out your filters and bleeding the system might also help. If that is no good you could rig up a jury daytank to gravity feed the system.

That would eliminate any blockages in the pipes. Other fuel related issues are fuel pumps and injectors.

After that you might want to check compression in the cylinder.

Is there any smoke from the exhaust?

KCA

 

[Jenko]

Hi KCA,

We do indeed see smoke. When starting, it normally chuffs out white smoke, but while running, there is normally a black 'soot' left in the water.
At lower revs this seems to go away.


Thanks for the feedback. We will try your suggestions.

Thanks.

Paul.

 

[chrisc]

Are you sure that you have no water in fuel ?
mine had same symptoms before a lengthy and
difficult clean out --'white smoke' when starting sounds
like water in the cylinder from somewhere and the black
soot is a sign of inefficient ignition.

 

[vyv_cox]

Failure to reach full revs is very often symptomatic of a blocked filter. Most likely cause is sludge in the fuel tank - many threads on this in the archives. If you don't have one already a primary filter is very useful in protecting the finer, secondary filter from both water and sludge, although it does have its limits, of course.

 

[andy_wilson]

Black soot

You haven't by any chance blocked up the engine room breathers recently have you, for instance by adding sound insulation. Black smoke is a classic sign of lack of air, so check the air filter (if fitted).

The other alternative is too much fuel, or put another way too much load.
How does the shaft turn by hand when in neutral?
(this might suggest a shaft/P-bracket problem).
What happens if you tie up securely and run hard in reverse?
(This might point to a gearbox problem).
Is the prop. or boat bottom heavily fouled (have speeds under sail declined)?

It would be worth drying her out to take a look at the underwater bits, or having a quick dip over the side with a mask before the water gets too cold.

I would also whip the injector out and inspect the nozzle. If you re-couple the high pressure pipe and turn the engine over this will reveal either a fine mist (good) or an uneven shower (needs servicing).

 

[david_bagshaw]

Re: Black soot

Tying up & running in reverse will not necessarily give the correct answer as many healthy engines & installation, will not run at rated RPM due to unusual loading on the prop.

This was certainly so on our previous boat.

Although I have no experience of the Volvo MD1 B, and although it wont affect the cutting out , have you checked the valve clearance, as this will affect top power and in extremes starting and black smoke.

Small air leaks in the suction side of the fuel system can also lead to your symptoms as well.

All the best

David ps Take a look at my site www.yachtman.co.uk