Volvo Penta MD 1

[ferrispeterchris]

I had my engine running before I bought the boat 3 months ago but now I seem to have lost compression! Took the valve cover off today and the valves seem to be working ok.Could it be sticky rings? If so can I free them without taking the head off? Peter.

 

[bdsweeting]

I don't know that engine but one thought arises... does it have a decompressor fitted, if so is it closed or open?

Maybe the engine is worn a bit and one way of improving compression is to add some oil to the cylinder. Now this is obviously a bit tricky with a diesel as you can't just pull out a plug and put some in.

What you might be able to do, however, is to turn the engine over with the fuel rack set to max to get some fuel into the cylinder. Let that rest for a moment or two and then retry a start.

No promises but hope you solve your problem.

 

[boatmike]

I think the MD1 is the old heavy slow-revving single cylinder with a valve lifter and a bloody great flywheel on the front?
If so, check the valve lifter is set properly and is not jamming. If the valves are closing OK then they are either burnt out, or you do indeed have jammed and probably broken piston rings. It is in fact relatively easy to remove the head and cylinder to inspect, but it is quite possible that at an advanced age that replacement parts might make refurbishment uneconomic as the main bearings etc will also be worn. Worth lifting the head and pot to see though. You won't loose anything. For heavens sake though don't go to Volvo for replacement piston rings. Any Autopart stockist will be able to supply Hepolite or Cord replacements at a fraction of the cost.

 

[seaesta]

I ran a low compression MD1 for years.

Starting procedure was
1. remove air filter
2. Get oil can with flexible pipe type nozzle and filled with normal engine oil and prime it so oil is up to end of nozzle
3. get the nozzle right down the air inlet and put in TWO squirts of engine oil - no more
5 replace air filter
4. get the engine turning with decompressor open then close it quick
5, Run till warm before stopping

Mine started first time every time even after winter lay up using this method.

Martin

 

[ferrispeterchris]

Martin, what engine cycle are you on when you squirt? ie with regard to piston position. Peter. Ps I've read somewhere that 2 stroke oil is a good upper cylinder lubricant,any thoughts?
Just another thought.The decompression lever does not seem to reach/touch the rear rocker.I presume the lever works by opening this valve! Why or how can it not reach? Thanks, Peter.

 

[andy_wilson]

It's unlikely that something has happened in the intervening 3 months.

Are you sure it isn't the decommpression lever in the wrong place?

 

[seaesta]

Peter,

No idea about the position in the cycle - it did not make any noticable difference. I would not use two stoke oil except for 2 strokes - bog standard 20w40 does it for me!

I should have said that the MD1 allways stops with the exhaust valve open. An important factor in keeping them running is to wind the engine round until it is on compression before leaving the engine for any time.

A friend of mine found that his valve stuck when he left it open for a few weeks. It could be that your problem is a stuck valve - get the rocker box cover off and have a look. If the valve does not move in and out when you wind the engine round then you need to free it

When worn the decompressor shaft can move in and out and only engages in a certain position. Pull it each way and feel for the "bite" as it engages.

Martin

 

[scarlett]

I used to start my un-overhauled MD1 by using a gas blow lamp to warm the air around the inlet pipe.

No problem but for the phaph.

 

[sailorman]

dids u depress the cold start button on the aft end of the engine

 

[ferrispeterchris]

I can't find the cold start button! Peter.

 

[sailorman]

its just where the throttle cable attach's to the engine on the aft side.
the cold start button is a small !2m/m Dia brass button, open throttle & depress the button

 

[robpoulter]

Peter, I still have the original manual for my MD1, with diagrams, troubleshooting etc.
I'd be happy to send you a photocopy if it would help.
Rob

 

[ferrispeterchris]

Would appreciate that very much Rob. Peter.

 

[seaesta]

The cold start buton has a round top and a spring at the side. You can feel the spring when the button is not engaged. It only engages when the throttle is open