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MG Midget and Sprite Technical - 1500 won't start, again.
|Hi I recently built up the motivation to start work on my midget again, however I'm having trouble even getting it to start.|
There are a couple of problems, the first is possibly a battery issue. The engine barely cranks over, even when it is being jump started by another car, if I remove the spark plugs I can get it to turn over few times but it soon gives out. If I try to turn it over under its own power nothing really happens.
The other issue seems to be with the fuel lines/pump. I recently replaced all of the fuel lines and cleaned up the tank, I also removed the pump. Since then I have had trouble getting fuel to the carbs, I have tried two pumps, both of which work and attempted to suck fuel through the lines to no effect. The tank is half full.
The car does spark (albeit weakly) so that -hopefully- isn't an issue.
Any suggestions would be gratefully received.
|If the engine barely turns over when jump-starting, you could have a problem with the starter motor.|
Where are you connecting the negative jump lead to? Directly to the engine is best, for a number of reasons.
If connecting the negative jump lead directly to the engine improves things, you may have an issue with the earth strap to the engine.
|I have tried connecting the jump leads directly to the block and starter solenoid, no change.|
Is there a way to test the starter motor? It is a recently refurbished unit and hasn't yet given any issues.
|id stick the jumper batter in the car and try that... if its still turning slowly, then pull the starter for a looksy|
esp.look for corrosion on the starter to block mating surface
id say pull your battry cables to make sure there clean and no white greenish powder inside the windings of the bat cable
if the starter turns over fine, then the battry was just weak
|Prop and the Blackhole Midget|
|yes sounds like you have a number of issues|
a poor battery or one that's low on charge will hinder your progress - see Tarquin's thread about battery, starter and electrical connections
weak spark isn't good
as always with these things check the basics - battery, leads, connections, earths, starter soloniod, starter motor, low tension side, high tension side
for the fuel - is it making it to the fuel pump from the tank, is there a full or partial blockage in the supply pipe, is the fuel cap vent working (just leave the fuel cap off to test but put it back on straight after test don't leave the fuel tank 'open'
|I didn't think to remove the fuel cap, I'll give that a try.|
The main problem is the weak turn over, I've taken the starter motor out and tested it against a fully powered battery. It seemed to spin well and engage correctly, so I'm hoping that isn't the issue.
I think all the leads are good, I can't see any signs of corrosion and I have moved the jump leads around to try to isolate any problems.
I may connect the jump leads straight to the starter to bypass the solenoid, however I'm worried that I might break something?
|If its not the starter cos its spinning right then are you sure the starter is:|
The main shaft on the starter is not bent
Have you tried starting with the clutch depressed and does that make a difference to the spin speed?
Have you tried starting with the jump battery being one in a modern that is running when you try the midget? (makes a huge difference to flat diesels when the surrogate car has engine running) make sure you earth to a known good earth on the Midget. (start jump car after jump leads attached) tbh I havn't had to do this with my midget, a charged jump battery always started it before I got it back together.
There are two general thicknesses of jump lead wire and it makes a difference. The thin ones are hopeless for starting Midgets as well as diesels. I have chucked my cheapo set.
Be careful of how you connect the jump battery if you go for direct on the starter as you could 'melt a termnal', see big sparks, get a right whack off the battery or on mine it would be right by the petrol pump etc.
|Dave Squire (1500)|
|PS the thickness of the jump lead wire is not easily seen without looking at the clip ends as often the manufacturers make the insulation thicker to make them look like thick wire ones.|
|Dave Squire (1500)|
|did you read through Tarquin’s thread ‘Starter motor lazy’?|
is there anything you’ve not put like a recently rebuild engine or now much higher compression ratio?
starter motor is a recently refurbished so it should be OK but should isn’t the same as is
connecting a PROVEN good charged and condition battery (number of times I’ve been told the battery is good when it isn’t) to starter motor will test how well it turn in situ – usual safety bits about sparks, not being in gear, etc., and as Dave’s put being near petrol or fumes
as Dave has also put is starter motor fitted correctly and fully bolted tight making good clean contact
with good jump leads the wire thickness will be on the box or packet but even good quality thick wired jump lead will start to warm with the pull from the starter motor, have a look at the towards the end of this video for how hot things can get - http://www.youtube.com/watch?v=kgl7ikq_YOs&list=UU40j4KqUJPMVv4FQ29ro-xQ&index=2
of course even if it turns well it wont fire until you’ve sorted your fuel supply problem
|The starter seems to be in good condition. I dismantled it, cleaned the brushes, contacts, bearings etc and tried it again,nothing changed. |
Some thin red plastic is peeling from the windings, I don't know if this is an issue?
Could a short in the windings cause it to weaken?
The jump leads are fairly thick and I've used them to jump much larger cars than the Midget. I always keep the jump battery in the car, with the engine running, it's not worth the hassle of removing the battery from the car then resetting clocks and alarms.
The jump battery is new and in a large diesel, it should provide easily enough cranking power for a Midget, however it can't get more than a weak turn over for around 5 seconds (at most), this is with the leads connected directly to the motor.
|The insulation of the windings on the armatures is important. Each winding is effectively another 'magnet' all these adding up to a big magnet and therefore more power. A short in these will cause the starter to be 'weak' rather than 'slow' although when unloaded the motor will seam to spin fine and fast.|
If the engine moves OK by hand. (I use the fan pully to rotate mine, remove the plugs if you have good compression), then the chances are its a starter motor problem.
The big diesel and verified jump leads rule out anything else as far as I can see. And you have removed the starter for a clean up that infers there was a starter problem in the first place.
So if at this point then as Nigel says look at the starter in more detail.
|Dave Squire (1500)|
|Once you get it started I would check your points for corrosion, maybe causing your weak spark.|
|The points are brand new and still have a mirror finish.|
I tried my spare starter and the same thing happened, turns over once or twice (weakly) then gives up. I suspect that that one also has a short in the windings.
This thread was discussed between 29/03/2013 and 02/04/2013
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.