billskip
Well-Known Member
The fork that is moved by the solenoid slides the pinion gear on the starter motor rotor shaft ..into the engine flywheel ring gear. The starter motor rotor shaft has very little end thrust movement.
Engine not starting - advice urgently needed
- Thread starter webcraft
- Start date
vyv_cox
Well-Known Member
Depends on design. Rotation of the rotor cannot drive the pinion into the ring however it is configured.
billskip
Well-Known Member
With the inertia design the pinion moves along the rotor shaft due to the design of the shaft and the pinion ,the initial excitement of the rotor creates inertia for the pinion to travel along the shaft against a very light return spring enabling the pinion to engage with the ring gear...
With the pre engage which means the pinion is pre engaged with the ring gear
prior to the rotor being excited.
If you short the terminals making the motor run and making the solenoid work and the fork sliding the pinion along the shaft all at the same time, the pinion will be rotating before it arrives at the ring gear and the pinion will be ramed against the ring gear if it doesn't locate, then you will hear a nasty noise.
awol
Well-Known Member
The last pre-engaged starter I dismantled, probably over 30 years ago, was provided with a roller clutch to prevent over-run of the starter motor and aid disengagement.
For avoidance of doubt, shorting the studs was a very occasional rescue act when the engine was immediately required and the normal button failed.
For avoidance of doubt, shorting the studs was a very occasional rescue act when the engine was immediately required and the normal button failed.
billskip
Well-Known Member
Yes, the overun "clutch" was fitted to many types, and yes in an emergency get the thing going is priority...
More damage will be done to newer starter motors due to abuse because they are made much lighter and many are now fitted with plastic gears.
penberth3
Well-Known Member
Like molten copper in the eye? I'm horrified at all this advice to short across terminals connected to 12 or 24v batteries. Remember the OP claims an absolute minimum of technical knowledge. And so many forumites suggest doing something hazardous.
penberth3
Well-Known Member
First start of the day, check the engine. You don't bother with anything like that?
Sea Change
Well-Known Member
I'll admit that I don't go through every cable connection and check them. I do generally check fluid levels and give the belt a twang.
penberth3
Well-Known Member
That's more than a lot of people do. I think we're on the same wavelength!
Sea Change
Well-Known Member
Probably ingrained from a few years driving boats for a living.
Fluids, belt, strainer. Look over the stern for water flow.
In all these years, I can only think of one time when my glance over the stern led to me shutting the engine down again. The water pump had failed, thanks to my over zealous belt tightening. Maybe the people who just turn the key and don't give it any thought have the right idea
billskip
Well-Known Member
So what is your advice that helps the op?
ducked
Well-Known Member
Has been a pretty standard procedure on my cars, though I dunno about 21st century ones. Might be more of that negative progression thing.
A sharp tap with a hammer (rock, shackle, kedge, etc) can also help.
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billskip
Well-Known Member
Why didn't you fix it so it worked correctly?
How can that help?
Just curious....
ducked
Well-Known Member
Because sometimes, after I did it, the car started (I wouldn't go so far as to say it "worked correctly", but it worked well enough)
Whereas before I did it, it didn't
This was helpful if I wanted to use the car
I found cars helpful because they gave relative freedom of movement and the ability to move relatively heavy stuff around.
YMMV
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PaulRainbow
Well-Known Member
Nothing hazardous about connecting a positive supply to the spade terminal of a pre-engaged starter motor, it's what happens every time you start the engine with the key/button.
Oily Rag
Well-Known Member
Not having to have done what Paul suggests - or played with heavy screwdrivers near terminals - could I ask if anything has to be done with the diesel plug heaters before starting? Will it usually start cold?
Sea Change
Well-Known Member
Some engines don't have any sort of heater at all, and just need a bit more cranking before they'll start.
vyv_cox
Well-Known Member
Shorting between the spade terminal and power attachment only activates the starter motor, nothing else. When I had glow plugs they were energised by a separate button.
Leslie frank
Well-Known Member
I have had a similar problem in the past when one of the crimped connectors to the pos or neg battery wires had come loose. Try following these back to their sources checking the connections are sound
Mistroma
Well-Known Member
I think you will find that the fault was identified about 55 posts back in the thread.
