Volvo MD2B engine starting problem

[worlock]

Following test which confirmed poor compression ratios, I have performed a de-coke of my MD2B volvo penta engine and installed new liners and piston rings. The injectors have been tested twice and are know to be good. New batteries have been installed. Fuel seems to be reaching the injectors, but the engine will not start. I have used Engine Start sprayed into the air inlets and the engine will start but will only run as long as engine start is sprayed in !!!
Please can anyone give some advice.
Regards,
Mark.

 

[seamaster30]

Following test which confirmed poor compression ratios, I have performed a de-coke of my MD2B volvo penta engine and installed new liners and piston rings. The injectors have been tested twice and are know to be good. New batteries have been installed. Fuel seems to be reaching the injectors, but the engine will not start. I have used Engine Start sprayed into the air inlets and the engine will start but will only run as long as engine start is sprayed in !!!
Please can anyone give some advice.
Regards,
Mark.

May be a daft question, but did you re-test the compression after the rebuild? - Not sure if the piston rings needed to be installed with the gaps 'offset' (like in my old motorbike days), but was that done as well? - Possibly a leak in the cylinder head between the cylinders?
Other than that it must be fuel related - there can't be much else to go wrong.

 

[earlybird]

Since the engine runs on easystart, it must surely be fuel related. Assuming the timing wasn't disturbed during the overhaul, my guess is the feed to the injectors hasn't been fully bled. NB Easystart should be used as little as possible.

 

[ianat182]

Volvo MD2B Starting Problem

As you had the head off I assume that the valves were reground -in and regapped correctly. Another compression check could indicate,wrong timing, gasket leaks.That the Easy start does let it fire briefly seems to indicate fuel not getting through, so needing to be bled and mechanically pumped.
Go lightly with the Easy Start anyway!

 

[Kurrawong_Kid]

First try squirting a small amount of engine oil into the air intake of each cylinder so that the liners are not completely dry. The fact that it will go on Easystart for a few moments suggests low compression. Check that the decompression device is properly adjusted. If you reground the valves that will be necessary. Also make sure you bleed thoroughly at each cylinder including the leak off pipe at each injector and at the return to the pump.A seal of oil on the pistons might just improve the compression so that with another application of Easy Start it will keep going! Also have someone swing the engine at the same time as you press the starter to get the engine turning over at some speed. If that is O.K. then it should go.I post from experience-the're a pig to start after a rebuild. But once they've started you shouldn't need Easystart any more.

 

[Bilgediver]

Following test which confirmed poor compression ratios, I have performed a de-coke of my MD2B volvo penta engine and installed new liners and piston rings. The injectors have been tested twice and are know to be good. New batteries have been installed. Fuel seems to be reaching the injectors, but the engine will not start. I have used Engine Start sprayed into the air inlets and the engine will start but will only run as long as engine start is sprayed in !!!
Please can anyone give some advice.
Regards,
Mark.

DO NOT USE EASY START OR THE HEADS WILL BE COMING OF AGAIN!

IF problems starting then remove air filters and give a few squirts of ooil into each inlet and thren crank over decompressed before starting.

 

[Kurrawong_Kid]

Forgot! You can avoid using Easystart by warming up the air before it enters the airintake-warm air blower or similar.

 

[scottie]

Did you check the bump hight (compression ratio)it is adjusted by shims under the cyl blocks
have a look here http://www.marinepartseurope.com/en/volvo-penta-explodedview-7742090-21-13754.aspx
md2b does not have replaceable liners they start with md11

 

[[448]]

These engines will normally start as soon as the decompressors are dropped in. Loosen the injector unions when cranking, and there should be loads of fuel showing. Have you pressed down the excess fuel button near the pump before trying to start? Check for compression with the starting handle. As far as I know there is little difference between the MD2B and MD11 apart from the substitution of starter and alternator for the dynastart.
Dave

 

[elton]

Have you pressed down the excess fuel button near the pump before trying to start?

I was just about to mention that. It amazes me how many owners don't know that button exists or what it's for.

 

[ianat182]

volvo MD2B Engine starting problem

Thinking further about this.. check that the stop/start push/pull lever has been pushed fully back when you last stopped the engine. I get this problem mostly when new crew are asked to stop the engine and don't realise it is not a spring loaded lever that returns it. Hope that's it!!


Ianat182

 

[Jcorstorphine]

I had the same problems.

First thing is throw away the starting fluid. Engines become addicted to the stuff.

Next be very careful about adding oil to the bores as if you overdo the dose, you will risk a hydraulic lock.

When you rebuilt the engine did you use “leads” to measure the compression gap. If you are unsure of what I am referring to, the technique is to feed a small length of solder wire into the injector hole and turn the engine until the solder is compressed. Carefully remove the solder and measure the thickness. If you refer to the following web site you will find a manual for the MD2B http://www.motoren.ath.cx/download.php?filename=volvo/md-1b-2b-3b.pdf which is in Dutch. Somewhere you will find what the compression gap is and the way in which you change the gap is to remove / add shims between the crankcase and the cylinder block.

Before you even try to start the engine make sure that the oil system is primed as these engine have the oil pump quite high off the sump (on the camshaft) and if the engine has seen a lot of hours, then the engine may start but the poor thing will then seize. (mine did) I used a vacuum pump to suck up the oil to one of the oil connects on the head but not sure exactly where)

You say that the fuel lines are fully bled but do it again to make sure that the lines are still free from air.

Press the cold start button at the rear of the engine (small brass mushroom thing) which should stay down and get hold of a hot air gun (paint stripper thing) remove the two air filters and heat up both air intakes for about 5 mins, Now concentrate on one of the intakes and blast in some hot air whilst at the same time cranking the engine with the de-compressors closed (unless you are starting by hand)

The engine WILL fire under these conditions on at least the one cylinder, move the hot air gun to the other cylinder and that should cut in. Keep the hot air on until the engine will run unaided.

Hopefully a carbon ring will start to form round the top of the pistons but you may find that the engine smokes a lot when started. Get the engine under load as soon as you can and if you are afloat at a berth tie the boat securely and run the engine in gear for at least an hour to bed in the pistons at about 1500 rpm.

If you work though these steps you should get the engine running, my engine went on for a further 10 years before the next owner of the boat replaced it due to rust in the water jackets.

Regards

John