Diesel wont start

[tonyd]

My Fuji Robin engine Matchless wont start.
The engine spins very briefly and then the starter can do more.
I have put in a new battery and changed the starter but the symptoms remain.

This engine has an automatic decompressor and I know think this device has failed and the starter is trying to work against the 20:1 compression. HELP
My email is tonydymott@hotmail.com.

Thanks
Tony

[gilburton]

I never stripped my engine down but I never had to use the decompressor.
I had a 14 amp battery in mine. Is your battery powerful enough??
Does the engine still turn over by hand or does it lock up??
All I can suggest is to double check the timing etc.

[Diesel Dave]

The engine spins very briefly and then the starter can do more.

I'm not sure I understand that sentence fully.

So with a fully charged battery the starter motor can only turn the engine over a few times before giving up and you suspect the auto-decomp has failed.

Can you turn the engine over on the kick starter - either proving the decomp theory or managing to start it?

If the above proved the decomp to be working then I'd suspect the starter motor is beginning to fail - see how hot it's getting after trying a start. Sometimes it can be a simple matter of needing lube in the end bush.

[tonyd]

Thanks for the responses.
The motor is turned by the starter only a part of a turn then no more. The starter motor has been exchanged. The battery is new. I did get it to start once and it ran fine and then back to no go.

There is no kickstarter fitted.
Is there an automatic decompressor on this motor to give the starter a chance of getting past the 20:1 compression?

Tony

[gilburton]

Even with the high compression you should be able to turn the engine over by hand.
That's why I was asking in case you have some sort of mechanical lockup rather than just compression.
Can you get a socket on to the crankshaft??
If it has a decompressor the lever is on the rocker cover and opens a valve and gradually closes up as the engine spins.
There is no "automatic" decompressor.
As I said I never used the decompressor on mine as the starter was more than enough to spin it over on compression which leads me to think that you have a problem somewhere.

[Diesel Dave]

Well looking at the Operating Manual there certainly isn't a manual decomp.

http://www.crommelins.com.au/media/docs ... MANUAL.pdf

However looking at the parts book, there is a 'release lever' on Page 16 item no 35; and it appears to be centrifugally powered.

http://www.crommelins.com.au/media/docs ... MANUAL.pdf

If it's stuck (is the motor used often?) then your going to need to get creative or strip it down to find out.

Regards
Dave

[gilburton]

You've posted the operating manual twice rather than the parts manual? lol
Anyway I believe the DY series has a device that operates as a decompressor when shutting the engine down??
All I can tell you is my DY41 had an actual manual lever on the rocker cover which unwound itself as the engine turned on the starter.
I would agree that the parts manual doesn't show this??
I found that it took too long for the engine to start, using it, that I never bothered.
It's difficult to diagnose a fault without seeing/hearing the engine but does it seem to lock up when trying to start it or does it just seem more like a flat battery so that it can't turn over??
Possibly a bolt has loosened and locking up the flywheel/starter ring??
I know these engines always stop in the same position as I had a problem with my starter ring gear.
You could take the starter out and check the ring gear through the hole?
Personally I would take off the primary cover to see if the engine turns freely. I used to be able to turn the flywheel by just gripping it but you should be able to get a lever on the sprocket??
Does the engine rotation feel loose when it's not on the compression stroke or does it feel stiff??
You could always take out the injector to see if no compression makes any difference??
If it's not locking up or feeling stiff then I would go back to the starter? Either it's not getting 12-13v (battery/earth/solenoid) or the starter is faulty or not correct for the engine??
Have you tried putting a good battery directly to the starter?

[tonyd]

Well it has not locked up as it started once.
Tomorrow I will try a battery jump leaded direct to the starter as I have not ruled out a poor earth or supply lead yet before I delve further.

Tony

[Stuart]

It maybe that either the Positive, Negative or Main Earth wire crimps are failing under load? Might account for some 'action' before it stops?
If make a new braided earth lead and fit it. Spray some lube on any 'dry' metal to aid conductivity.
http://www.dieselbike.net/Fault1/Fault1.html

[tonyd]

Well, I jump leaded the transit van battery direct and had the same result. Partial turn of the engine then stop. I believe that rules out connections from the battery to the starter motor.
I then noticed something odd. When I tried to push the engine over in gear I had an effect like clutch drag
Now wondering if something is wrong in the primary drive- worth a look before I start dismantling the engine. If I cannot see anything I could try it with the primary chain off.
All jolly good fun and instead of three bikes I am down to one 90 yr old that started first kick as usual.

Toodle pip

Tony

[sbrumby]

Take out the injector to see if everthing turns as it should.

[tonyd]

Good advice from you all. Overnight I had a thought that perhaps a stone chip had got into the starter ring teeth. I did not see it on checking but bike seems to start fine so its going back together shortly with the second battery in parallel as I know from past experience that when winter comes that will be most helpful.

Best regards

Tony