Bad earth

[robobobo]

Hi all
I've had some slow cranking no starting issues. Some new earth straps are on the way, I cleaned up the main battery earth but no joy. It does get very hot when cranked over so I'm guessing earths are the culprit. I previously did away with the nosecone earth and fitted a new starter earth as well as a hot start relay. Just wanted to check the usual location of an engine bay earth. I had an engine change and wonder whether they fitted the earth strap back on as I can't see anything

One change recently is that the main alternator bracket is broken so I have fixed up a temporary solution till I can drop the engine, would the fact that the alternator is not earthed as well as it was previously affect the starter cranking?

Don't think the kit will arrive in time for my camping trip for tomo so was hoping to try and clean up the engine bay earth if I can find it .

Cheers

[Mocki]

there is no engine earth as such, just a thin braided strap onto the LHS head from near the coil for the ignition and senders

the gearbox nose strap is the main earth, i suggest you reinstate it , two good earths are not a bad thing.

one of the issues i have found over the years is the starter motor face to the bell housing gets corroded, so i clean that mating face up AND the starter bolts and where they tighten to .

your problem may well be the ollite bushing for the starter pinion in the bellhousing ???

[bigherb]

If the battery earth strap is getting hot then the starter is pulling excessive amps. Either a defective starter motor or a very worn starter bush or event the engine is too tight to turn over.

[marlinowner]

It can only be a starter motor taking excessive current or a fault in the battery earth lead area. Bad earth anywhere else would not heat battery earth cable.

[robobobo]

Ok thanks.
I tried to test the starter by jumping the spade to the main nut on the solonoid with the ignition on. Was this correct or should I connect the battery supply directly to the main nut on the solonoid. Nothing happened anyway

The starter was a brand new aftermarket one and I replaced the oilite bush at the same time a year ago. Should have gone with a recon Bosch I guess. Most the time it's been starting on the button but over the last 3 months getting slower and slower. Hope it's not the engine

[Mocki]

It can only be a starter motor taking excessive current or a fault in the battery earth lead area. Bad earth anywhere else would not heat battery earth cable.

Not strictly true , a poor earth to the starter can go high resistance
Making the earth strap ( and live cable too ) hot

Bridging the trigger connection at the starter will only operate the solenoid the same as turning the key , if the starter or the earths are poor you wouldn't see any difference

Ignition timing too far advanced also results in slow turning in some cases as the sparks dmoesnt happen at the right time and the cylinders are compressing unexploded fuel mixture


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[robobobo]

The battery + cable didn't get hot, I'm going to try hand crank to see if the engine and AC pump is free. I already checked voltage at the starter and it's getting same as battery.
Really not looking forward to replacing the starter again, it's a syncro so it's a bit tight in there.

[robobobo]

Also I disconnected both ends of the battery earth and thouroughly cleaned them. I fitted heavy duty earth from the starter bolt to the chassis last year and it all looks great and clean. Yesterday I also jumpered between battery - and earth to the starter and no joy. So I guess if it cranks by hand then it must be starter or Bush.

I think the only mistake I made was that the ignition was on when I bridged the terminals on the starter but not cranking, I think I need to bridge the terminals and then turn the key fully?
I've looked at a few bits online but am a bit confused by the starter test.

[Mocki]

as i said above, bridging the trigger wire on the solenoid will prove nothing, bridging the two big terminals will do you no good, it needs the solenoid to "throw" at the same time

it does sound like a lazy starter ..... and if adding power by jump leads off another battery makes any difference it pretty much backs that up ....

[robobobo]

Ok, ta. Looks like a new starter then scraped knuckles here we come.