volvo penta md5a

[mj81]

Hi,
My GK24 is fitted with a 1980 MD5A Volvo which won't start and i have run out of ideas. Iniatally the compression was bad so i took the head off and got the valves reground as they were in bad condition. I have also got the injector serviced. She is getting plenty of fuel and the compression seems to be good but i still haven't evan got a kick out of her. Even when i got desterate and resorted to easy start she didn't evan kick. Any suggestions or should i just make it into a coffee table?!! Any suggestions would be greatly appreciated.

 

[Clyde_Wanderer]

Have you checked to ensure the valve timing is set up correctly, as if not, she could be reaching top dead centre with an open valve and would as a result never start.
It is also critical that the injector pump timing is correct.
I assume you have done a compression test since you lapped in the valves?

 

[Clyde_Wanderer]

Sorry I hadent read your post correctly.
You say it is getting plenty fuel and good compression, what you need to ensure is that it is getting the fuel injected at the right time, as you say "plenty fuel", but could be injecting a few degrees out of time, and this will be enough to prevent starting.

 

[gandy]

Any white fumes from the exhaust? If not, maybe the injectors aren't bled through. If it's injecting then the fuel's got to be going somewhere.

 

[Taffy]

Hi, I had the same problem on mine and I traced it to the stop control level. The lever is attached to a shaft with a grub screw which becomes loose. When pushing the stop handle back in it does not push the lever back to the correct position for start. If the lever is not fully home the engine spins nicely but will not fire. You can reset it by hand to check it.

Regards,
Taffy

 

[Clyde_Wanderer]

Would have thought he wouldent have any compression then.

 

[john_morris_uk]

When you say 'good compression', what do you mean?

Diesel engines in good condition are almost impossible to turn over by hand against the compression. Can you borrow a diesel engine compression tester to see what the pressure actually is? A car type that you hold in place isn't good enough (you could never hold it against the diesel engine compression either) It needs to be one that is bolted in or screwed in place of an injector or preheat plug and that will measure to the correct pressure.

I have had experience of similar engines, and it was worn rings and bores in the end that mad the thing refuse to start. The fact that 'easystart' doesn't give a bang either is worrying.

 

[gandy]

On the MD7A the stop control doesn't decompress the cylinders, it shuts off the fuel. The MD5A could be the same.

 

[smiala]

rebuilt my md5c type last year, as suggested above for a check try turning her by hand on the flywheel. If its easy you have a problem with compression still, it should be very differcult on the compression leading upto tdc on compression stroke.

Forgive obvious, but then ring/boar/piston, and or seats/tappets problem, or gasket could be your problem. Seeing you said the seats where poor, did you notice or feel the cylinder condition whilst the head was off. A lip near the top front/rear would indicate wear.

To start do check the cold start is ON, I missed that for half an hour whilst turning, on my first attempts.
To start use full throttle, cold start on, and turn away, should go in 10 secs.
Air bleed would be the next on my list, or have you tampered with the fuel pump ? best of luck.

 

[Heckler]

number one, if you use easy start it will start whether there is fuel there or not or whether it is timed right. the only other thing to stop it starting in that situation is poor compression, a common fault when "amateurs" grind valves in is that they dont set the tappets correctly and in that case the rockers will prop the valves open and she will not start!