Thread: Is my logic sound?

It may be that the starter is drawing too much current.

Any way of checking that( multimeter etc) .. the generator is relatively new so should be ok but I'll check it tomorrow...( dame fast awnser&#127867

Auto Electrician should be able to do a load test with a tong tester.

Hi Mark

I'm not far from you .

Batteries have a theoretical internal resistance . If you look at it this way, the starter motor resistance , being in series or in line with the battery internal resistance . As you press the button the high current demand of the starter motor will cause a voltage drop across the battery resistance , the battery voltage will drop from 13 Volts down to as low as 8 Volts. If the battery internal resistance is higher than its normal working value ( a dud battery) , then precious Volts will be lost at the starter motor. This is why some cars have a ignition coil rated at 8 Volts , there is a resistor in series with the coil for normal driving, but when starting the resistor is bypassed and the coil gets the 8 Volts.

Cheers. I'll have a look at how the battery's discharging under starting, I realy suspect it... I'll grab a decent battery and check it out if the multimeter during starting looks dodgey..... just kinda pointless trying to tune it with the starting issue interfering ... there's enough wear between the fuel system and ignition on this old girl to deal with an electrical supply issue
( yea close... met out at you're place with that flat hood stick exmoor trim god u patterned and shifted a windscreen loop on for me,must have been 3 years ago)
Cheers mark

Simplest way of checking whether the battery is the problem is to temporarily swap the battery for a known good one.

But also check for bad connections. These can be found with a multimeter by checking the voltage between the battery live pole* and the starter, and between the battery earthed pole* and the body of the starter when the starter is operated. None of these should be over about 0.5v, if they are, check the path bit by bit to find the problem, usually at connections of some sort.

* I have used these terms rather than + and - so it applies whether the original positive earth is still in place or the system has been changed to negative earth.

John

When its cranking over you're not getting spark.

when you stop cranking if its flooded as the engine speed drops off it wont fire.

thats why it goes on the second crank sometimes. First time you dont have the fuel air mix to go, second time you do.

if you have a meter with a max/min hold put it on the battery so its reading 12V hit the min hold setting and crank the engine. anything below 10v is bad and needs investigating.

if the battery is over 10.5 start following the leads around the ignition side of the system and if you get less than 10v while cranking you need to fix that problem.

Dont forget that you need to check with the meter earthed on the battery post to start with to rule out the battery and onto the block (or wherever your distributor points make earth to.

best of luck. and dont forget the condensor if its fitted.