Running Problems

[Bulldog Bri]

For a while now I've had trouble with the running of the Bulldog. When cold its ok but after its warmed up the problems start... 

The car will Idle Ok, but when I raise the revs it starts to cough as though on 2/3 cylinders. but once I've pushed through this and reved harder it clears and runs fine at high speed.

I've today changed over to Electronic ignition, No difference... checked timing, No diference... changed spark plugs, No difference... Spark leads, No difference. Checked the float in the carb it lifts on reving nicely, No difference. Plenty of fuel getting to the carb.

I've got to the point where I think something in the dizzy has gone.

[robp]

What carb have you got, Bri?  SU?  Single or twin?  Got waxstats on the main jets?

[Bulldog Bri]

Standard inch and a half SU. standard neadle set up.

[bluehornetrider]

Sorry to hear your having trouble with the engine running, wish I couod be more help, pretty sure you know far more than me.  Is the engine another triumph 1500? 

['Mendip Wurzel']

I would probably be carefully stripping the carburettor on a nice clean sheet, and blowing out all of the jets and crevices to make sure there are no blockages or maybe bit of water where it shouldn't be.....

[Sumov8]

Bri

I had similar issues with my Rover engine and it  turned out to be a faulty condenser, it would work at low and high revs but not in the middle it would start coughing and spluttering, I was looking at fuel for a while until someone advised me to change the condenser,  £3 and 5 minutes to replace.

May be worth a try if you still have one built into the electronic ignition.

Steve

[paintman]

Might be wrong but i thought the job of the condensor was to condense the voltage from the coil at the precise moment the points open, thus reducing points wear.

You won't have one if you got electronic ignition i would have thought.

[Bulldog Bri]

I changed over to the electronic ingition kit to give better starting and get rid of the occasional cough that would happen, this kit gets rid of the points and condensor, so there is no moving parts to wear out, To me it just feels like the advance in the dizzy isnt working then suddenly is  but as soon as the engine comes back down to a low rev it will idle ok until I want to drive off again. It revs nicely once I'm over a certain RPM! The other strange bit is, its worse once the car has warmed up!

This is th type of kit I fitted (in sub zero temps.  )

No, it's not a Triumph engine. it's a B series Engine from a Marina. (Big bro' to a mini engine )

And today is not the best of days to be playing outside changing dizzys 

['The Gaffer']

Leak in vacuum somewhere?

[paintman]

I should have thought you could pick one up for peanuts at the local scrappy to eliminate the dizzy.....Marinas not very popular these days.

[Hairy Santa]

is the base plate moving if  you suck on the vacuam tube, if so how much - check manual  - might be wrong dissy internals

check the outlet on manifold for vacuam at tickover through to medium revs and then back down again

try different grade of oil in carb dampers, and are the pistons running freely in the pots  ( do the finger drop test ) 

[Bulldog Bri]

Spent the day (between hale showers) checking over everything again. tried a different coil. took the dizzy out and checked that incuding the vacumn plate, all moving nicely. Still plenty of fuel getting to the carb and with the air filter off I can see the fuel coming into the carb and the float lifting smothly. I did fin that the center button in the dizzy cap was broken so changed it but it's still the same. Could it be a valve sticking open? Not had the chance today of doing another compression test. 

[Bulldog Bri]

Put a stobe light on the car yesterday and when the problem starts its not flashing but as soon as the engine wakes up and revs the strobe works!?!? tried this on all leads and plugs and the result was the same, which was strange as the engine runs at the low revs with no apprarent spark going anywhere till the higher speeds. I almost 95% sure its to do with the dizzy now so a new one is on order. In the meantime I'll work on Annas car doing small bits in readyness for putting that on the road in a couple of months (I hope).

['The Gaffer']

Can you run another earth to the block straight from the battery and try it?

[benchmark51]

Have you checked the centrifugal advance bob weights and springs under the dizzy base plate?