intermitant cutting out at idle

[steve92]

eh ups! been having a few problems with the bus cutting out at idle. started a couple of weeks ago on the way home from whitby. it was cutting out only at idle about half the way home, then the rest of the way it was fine. thought it may be some clag in the carb that sorted it self out, but its been doing exactly the same this weekend. dont understand why its fine sometimes and then not. am wondering wether the coils on its way out? its a stock 1600 with 009 and petronix elec ignition. plugs and leads have been recently changed.thats why im thinking coil, as its the only thing ignition wise i havent changed. cheers steve.

 

[ProfessorWheeto]

Might be worth rechecking your points gap and then resetting your timing.

 

[noddy]

I would also check that the electrical connection to the fuel cut off solenoid at the solenoid and the coil, also worth checking is the solenoid is well screwed in to the carb body.

 

[steve92]

Might be worth rechecking your points gap and then resetting your timing.

me points were junked for an ignitor kit.

 

[steve92]

I would also check that the electrical connection to the fuel cut off solenoid at the solenoid and the coil, also worth checking is the solenoid is well screwed in to the carb body.

cheers ,will check that out.

 

[steve92]

took the bus out yesterday, it didnt cut out, but it was ticking over at lower revs than normal. also i dont think its pulling quite as well as normal, and also i heard it popping back in the exhaust when im off the gas.would this be timing?

 

[noddy]

popping on over run is usually caused by either, valve clearances or lean tick over mixture.

 

[Lang]

Sounds like airleak on the carb, when the bushes on the spindle wear they let in air & your tickover becomes erratic. Volksworld february this year showed you how to repair them (easily). It costs about £11.00, bloke on evil bay is selling the bushes.

 

[Benyon]

popping on over run is usually caused by either, valve clearances...

Sorry to hear your having problems Steve, Not what you want to hear but I had probs with back firing/ popping and engine stalling at idle... ended up being a partial engine rebuild/redress with new piston rings, valves and guides!! :shock:

But I'm sure your won't be that serious :lol:

 

[VWAIRCOOLED]

First thing I would do is see if it is all cylinders affected or is it down to 1 or 2 of them.Get the engine running at idle,speed it up a bit if you have to.Then pull a lead off the cap using something insulated so you don't get a shock .Then note any engine speed change and plug the lead back on.Do this for all 4 leads.Then do it again to be sure.If you found 1 cylinder which wasn't changing the engine speed then start looking at that cylinder.First thing you would of noticed right away is if there was any spark when you pulled the lead.Next check the other end of the lead (pull it off the spark plug put a spare one on,rest it on earth somewhere and start the engine) Next pull the plug and check/swap for a good one.Next check compressions on all 4 cylinders.If one is down then you'll need to get the engine out and take the cylinder head off and check it.Probably a burnt exhaust valve on number 3.

It's hard to see what is wrong without seeing it.If you pulled all the leads and each one dropped the engine speed then check for air leaks around the inlet manifolds on the heads,the rubber boots on the manifold,the carb base gasket,and as someone said the carb itself.You can do this by spraying a suspect area with something.I use a tin of aerosol brake cleaner,this is flammable so be careful.Get the engine idling and spray an area at a time and look for engine speed change,if you find any change do it again to be sure.Careful when you get to the carb end,you can get speed change from the brake cleaner entering the carb normally which could lead you to a false reading.When you're spraying things give them a little wiggle to see if it opens up some gaps/splits.

 

[dagboyblue]

i get the same problem on my single port - originally i had zero pressure on 3 and 4 so stripped down (with a mate) and found that the exhaust ports on 3 and 4 had blown and there was also a crack on the head in 3

changed over the heads and all went sweet - until now anyway, the stalling started again a couple of days ago and i have done some checks and it looks like 4 has gone down??????

this is starting to piss me right off

 

[rustydiver]

I had the same problem on mine last year, i changed the rubber manifold boots found one side was starting to perrish. Havnt had the problems since. Worth looking at the samll things before the biguns.

 

[noddy]

Steve I would do the basics first.

Check valve gaps are 0.15mm

Check carb tick over settings fuel mix rpm etc.

Condition of plugs

Condition of cap and rotor (I usually put a new cap and rotor on every year).

Timing settings.

All these are the least costly to do, if problem still persists the as mentioned start looking for air leaks, and get a compression test done.

 

[steve92]

ok cheers guys, ill check the simple things first, and keep everything crossed!! :?

 

[steve92]

ok, so ive been busy checking the simple things first. checked over ignition side, and things seem ok. have reset the valve clearances today. not one of them was correct!! have just taken it out for sea trials, and things are looking promising! it didnt cut out, and pulls much better. also the popping in the exhaust has gone. during my checks though, i noticed the plugs were a bit sooty.they were dry though.so i guess its running rich.so my question is, would incorrect valve clearances cause it to run rich? think im gonna get my local dub garage to check the timing, and the carb set up to be on the safe side.

 

[noddy]

Sooty plug maybe down to several things.

Rich tick over mixture, you will usual get a smokey exhaust if its real rich, or the exhaust will smell of petrol.

Could also be oil bypassing the valve guides or the piston rings, but if all your plugs are sooty its probably mixture set up.

How long have you been running since your last valve adjustment? (how many miles approx)

 

[steve92]

this is the first time ive checked them. had the bus nearly 18 months, and done a couple of thousand miles. yeah all the plugs are sooty. dont think oil is bypassing, as i have just done an oil change, and this is the first time ive put oil in it, it just doesnt use any.

 

[dagboyblue]

my prob seems to be the carb/choke checked plugs, leads compression on each cylinder - got a feeling the choke is shot

 

[dubscum]

i had the same problem, my carbs pure fuel jet is blocked and its a bit old and worn out theres not alot of adjustment on it. I messed about with it (small screw on the carb) now it idles fine and over 3000rpm is fine but under that its very lumpy, but will do until i can afford a new carb. Never tried before and it was easy

 

[steve92]

my prob seems to be the carb/choke checked plugs, leads compression on each cylinder - got a feeling the choke is shot

glad its not anything more serious!