GTA atmo not starting

Mr273 ..yes the gta manual
It is on this site..technical help...gta...manuals..engine...b29 onwards..click on the page..just shows as a ? Icon..but the content is there...
Page b30 talks about 2 idling jets ...maybe take a look at these instructions..maybe improved over the 310 content...

Took it out for 30 min run. Then returned to losen the idle screw straight away. Did this with the air cleaner removed - the manual says leave it on - not sure if that make a difference. The idle speed increased to 800 rpm. Started from cold this morning and the problem persists. Since I didn't have a cold idling problem before changing the cap and rotor, I wonder if something related to the choke was disturbed. Can't see any problem with with hoses etc around the distributor and throttle cable seems fine.

Mine is the same it was working one day and has not worked since I am not wasting any time on it every-time I drive it the tick-over does something different ...will be saving the pennies for Holly conversion The last time I competed it developed a bad misfire the bottom end had leaned out so much we took the vacuum pipe off tie-wrapped it up and enriched the mixture, nothing loose no pipes off and that's with the air mixture screw wound all the way in, must be a diaphragm gone or something. I just cant be bothered to pull any of it apart again The bi-metallic seems to be operating the choke ! I might swap the small carb over from my spare set up and see what happens, but I cant remember why I took it off in the first place!!

Please let me know if you find out what the cause is?

Prior to the attempts; I set the static timing and dwell,....

John.... can you just confirm how you set the dwell angle, and in which order you did the static timing and dwell adjustments please.
John

[johnb]

Prior to the attempts; I set the static timing and dwell,....

John.... can you just confirm how you set the dwell angle, and in which order you did the static timing and dwell adjustments please.
John

I set the two sets of points first at 16 thou each as a starting point for approximate dwell before mounting the distributor to the rocker cover. I then set the static timing at 10 deg BTDC (cylinder 1) using the 10 deg mark on the timing chain cover plate against the pulley mark for cylinder 1 at TDC. This plate I had set previously at TDC on the firing stroke of cylinder no 1 using a drill through the block into the hole in the crankshaft web with cylinder 1 on the firing stroke.

I then checked dwell whilst cranking the engine using Gunson multimeters, I bought 3 different models in the end on ebay and they all gave comparable readings within 5 degrees of the MDR figure. You can never have enough auto electrical meters I've now found, don't know how I managed without. There was a slight difference between the readings for the two sets of points but I considered them close enough to attempt a start. The plan was to then recheck dwell with the engine running and adjust the points gaps if necessary.

The plan now is to double check everything, maybe take the carbs off again even though I did a complete strip and overhaul previously. I may have missed something.

[johnb]

Just to add. Once the engine is running and if the dwell needs to be reset I believe I'll then have to reset the static timing due to the dwell change affecting the points opening position. Is that correct?

OK John... thats fine, as long as the static timing was set after the points were set. I was just a bit worried that having used the word "Dwell", it had been done by cranking... but you know my views on that via the PM's.
The other thing that concerns me is the 10.6 v " AT THE BATTERY" or have I misunderstood that. If the battery was new, I would not expect it to drop that far when cranking.... at the starter..yes, but the battery should hold at 11.5 to 12v I would have thought. If it is 10.6v at the battery, imagine what it will be at the coils ????? I think I would give the battery a very good charge before cranking again... perhaps a good clean with emery paper the battery posts and cable attachments.
But with regard to starting... the ign seems good enough to, at least, start.... perhaps not for perfect running, and you have fuel...... here goes my enquiring mind again ... I take it the petrol for the lawn mower was not 2 stroke pre mixed ??? I guess not.. but I had to ask.... please excuse my questions.
Remembering, from what you posted originally, this engine has not run for 28 years... There is an old trick..... When trying to start carburettor engines which have not been used for a long time,... it is easy to flood them via the accelerator pumps, this will make them reluctant to start. what is worth a try is... (battery fully charged) depress the accelerator pedal very slowly to the floor... which will not operate the accelerator pumps.... then start cranking the engine with your foot on the floor... now this by passes the idle part of the carb and you hopefully start on the main jet.... keep the crank going and the engine should start coughing then one or two pistons will start to fire and while still cranking, the others should burst into life..... should you be lucky with that, as soon as it seems to be running... quickly start coming back on the pedal.... dont let the engine scream away... try to hold the revs at about 1200 to 1500 rpm whilst warming up the engine, then slowly come off the pedal on to idle. It is worth a try..... and oil pressure should come up with the extended cranking... but come off the floor with the pedal asap. Give it a try and let us know what happens. Good Luck.
John

Just to add. Once the engine is running and if the dwell needs to be reset I believe I'll then have to reset the static timing due to the dwell change affecting the points opening position. Is that correct?

You posted that while I was writing.... but yes.. that was the point I was trying to check. By adjusting the points, the static timing will be upset.

[johnb]

Mr273 ..yes the gta manual
It is on this site..technical help...gta...manuals..engine...b29 onwards..click on the page..just shows as a ? Icon..but the content is there...
Page b30 talks about 2 idling jets ...maybe take a look at these instructions..maybe improved over the 310 content...

I have looked at this previously but will have another look, thanks.

[johnb]

In answer to johnC:-

I'll do a bit of investigation about battery voltage when cranking. My Gunson's Testune book states " as the starter draws a high current under load the voltage at the battery drops to 10.5 - 9.5 volts depending on temperature ". This is why I thought thinks were OK. I did wonder about the voltage at the coils though.

Not two stroke mix John, what do you take me for? Understand where you're coming from though, process of elimination.

You're probably correct about possible flooding so I'll try your approach. First thing is to sort the starter motor which gave up the ghost when I was trying the starts a couple of days ago? At first I just thought I'd flattened the battery but after a recharge the starter solenoid clicks but no rotation. Guess I'll have to take it off to investigate. Exhaust manifold off again, etc, etc.

Not two stroke mix John, what do you take me for? Understand where you're coming from though, process of elimination.

Yes... sorry about that... its just the way my mind works..... every possible avenue must be eliminated.

I've sorted this on my atmo - I fitted fuel injection

EFI FTW

I've sorted this on my atmo - I fitted fuel injection

Seriously in how many years i have never had the carbs run properly! Nothing stays constant you adjust one day the next its doing the opposite...I have virtually given up on them ill only be forced yo do something once they pack up all together i guess. But a carb swap has to be high on the agenda as i want to get rid of the seriously overcomplicated pile of crap fitted by Renault ...lets face it they are 25 years old and they are only ever gonna get worse!!

The holley is reliable tunable simple gives more power for the same fuel economy ...its a no brainer for me now having decided not to go 3ltr fuel injected even fire and thats Mr Faulks fault. When funds allow i would like to build a tractable but high power normally aspirated odd fire lump to surprise a few turbos

First thing is to sort the starter motor which gave up the ghost when I was trying the starts a couple of days ago? At first I just thought I'd flattened the battery but after a recharge the starter solenoid clicks but no rotation. Guess I'll have to take it off to investigate. Exhaust manifold off again, etc, etc.

John... before you start taking the car apart again... it might be worth clipping your trusty meter on volts, between engine earth (not chassis) and the starter 12v ... not the "eye" connector with the starter cable coming out of it, but the actual starter stud thread. You should see 12v on the meter before you do anything... get some one to turn the key to start and see what the meter reads when the solenoid clicks. If the voltage stays at 12v .. I would say the starter was open circuit and needs attention ... However if the voltage drops to zero or thereabouts, I would be looking for a poor connection on either the 12v feed from the battery, or dare I say it... the earth return. Before you say "what do you take me for?" again... I know you have checked the earth's already but I have had experience of such a fault suddenly appearing without warning due to a poor connection in either current path, that's why I mention both.... but clearly your start point is the 12v path. Battery lug... starter connection.... also, if it is anything like the GTA, there is a break in the starter cable in a little black box on the bulkhead just above the gear box where the cable terminates under a bolt (this is where.. in the GTA, the feed to the ign switch etc, is taken off) then there is a second large cable that goes off to the starter from that same point.... this, and the other two 12v terminations need to be cleaned and re-secured just like you would have done with your earth points.
You might think... "Hang on... it was working one minute then not the next ... how come?" .... Trust me .... very high current paths (starter) can, and do behave like this sometimes.
It still may well be a starter fault, but a quick check of the above may save further dismantling, and is well worth the trouble.
John

[johnb]

EFI FTW

I was waiting for this Lee. I know, I know.

Thing is I'm not accepting defeat yet, too early for that. I've hardly started trying to sort it yet and there must be lots of A310V6 & GTA atmos running, maybe not perfectly, on these carbs. That's what I tell myself anyway.

EFI possibly when, like si21' I've reached that point of frustration. Like I've said previously, I like the challenge.