Help - What an I missing

[rogersirs]

Hi Guys

I need help and guidance. My 36 Tourer is causing mischief, it’s an LC engine and standard other than an H1 SU carb and a Bosch 009 Dizzy. Late last year I had issues with rough running and lack of power. Investigations over the winter revealed a fuel pump cavity full of debris, so I removed the pump cleaned it out, blew through the delivery pipe and removed and cleaned the carb. 

Thinking myself very clever, I reassembled and following my release from lock-down went for a start. No joy and when I did finally get it to start, running is most unsatisfactory, booming exhaust, rough, won’t rev, no power and touching the throttle will either cause popping Back or stalling. Fuel provision appears OK, may be running a bit rich but it’s difficult to tell or adjust when it’s running so rough. I have checked and reset the tappets, replaced the coil and given the Dizzy a service (new cap, rotor, points and condenser) and it has a new set of plugs. Engine compressions are 100, 95, 95 and 100 so don’t see a problem there.

I am now getting a bit disheartened and think I must be missing something, any ideas? Having paged the forum I understand that supplied Bosch 009 units fall into 3 categories ie Good, Bad and Ugly. Is it possible this could be the issue and what issues should I be looking for.

[Nick Salmon]

Are you using really fresh fuel?

[Mark McKibbin]

Yes sounds like a blocked/semi blocked jet or bad fuel.
Probably need to undo fuel pipe from carby and turn over engine on starter (ignition disabled) and see if you are getting a good flow that at least will eliminate tank and pump. Although a couple of gallons of good fuel may be easiest.

[Ruairidh Dunford]

What is the history of your distributor?

[John Cornforth]

Hi Rogersirs

SU carbs are pretty immune to blockage, once the needle rises and the annular gap increases any dirt tends to get flushed out.  Sounds like you have enough fuel flow, but as others have suggested, check the flow rate. Failing to rev (i.e. misfiring or cutting out as soon as the throttle is opened) can be a sign of weak ignition, i.e. just enough volts to spark at idle but failing to spark once cylinder pressure increases and the voltage requirements go up. I find that fuel flow restriction doesn't have quite such an immediate effect.

If you hadn't already changed the condenser, I would have suggested changing it.  However, it's not unknown for new units to be faulty - do you have another known good one you could source to try ? Also, does the distributor have a good earth path to the engine block ?

[rogersirs]

Cheers Guys

I have just nipped out with my fuel can and now have 5 Ltrs of fresh unleaded. I have a small tuning tank in the garage which hanging from the ceiling will allow me to gravity feed the carb and bypass the pump and residual tank/old fuel. Will check dizzy Earth also and give it another go in the morning!

---

Unfortunately I have no idea, it was fitted to the car when I got it, so I have no clue as to the origin! I wondered if the issue could be related to it not operating beyond idle (perhaps not advancing). I also fitted a positive 6v Dyanamator over the winter period which does not appear to be operating, but I doubt this is related. For info it has Austin gears on both ends, but the Ign light stays on and Amp Gauge shows slight drain. I have spoken to Tony at Accuspark and on his advice have re checked wiring twice but no change. Until I can get the engine issue sorted however I cannot positively prove it to be good or otherwise!

Thanks for inpu!

["Slack Alice" Simon]

"pump cavity full of debris"

Have you drained the fuel tank and seen what comes out?

I'm draining mine after every trip, because I'm reluctant to put sealant in it until I really have to.


A 10 mile trip fills the cavity in the middle of the drain plug with crud, and I may well have to had stopped to clear a jet during the trip.


And I am fairly sure the rust mixed into the fuel is affecting the performance.


The cavities in the fuel pump and the carb bowl retain a very fine rusty powder which I clean out from time to time.


Have you tried disconnecting the delivery pipe from the tank at the pump end, attaching a tube, and blowing back through the pipe and into the tank?

I had to do that recently, a particularly persistent lump had blocked it completely.


I also had a wierd problem with the fuel pump, which slowed the car to idle, but that appeared only after 5 miles of normal motoring.

Cheers

Simon

[Ruairidh Dunford]

Unfortunately I have no idea, it was fitted to the car when I got it, so I have no clue as to the origin! I wondered if the issue could be related to it not operating beyond idle (perhaps not advancing). I also fitted a positive 6v Dyanamator over the winter period which does not appear to be operating, but I doubt this is related. For info it has Austin gears on both ends, but the Ign light stays on and Amp Gauge shows slight drain. I have spoken to Tony at Accuspark and on his advice have re checked wiring twice but no change. Until I can get the engine issue sorted however I cannot positively prove it to be good or otherwise!

Check the plate on the attached to the spindle has not come loose, it can be brazed if necessary.

Check the spindle for excessive play - if large, it can cause very rough running.

Check the rotor arm and replace with new - some have a component buried in them that fails.

There are some issues with Dynamators but Tony will sort you out, when you are ready.

[Tony Press]

Silly question- the timing is right ?

[rogersirs]

Hi Guys and it’s many thanks to you all!

I did some investigation/work along the lines you suggested and having done a 5 mile run today, the first since Sep due to being quarantined due to health issues,  other than one period of spluttering, all appears well. To close the issue and provide some feedback, this is what I found. 

I drained the tank and having initially had the issue with the blocked pump top I expected deludes of debris, but in fact there was next to nothing in the bucket. The fuel however was not good, it looked like weak tea, not clear like the fresh stuff in my can. Looking further, I noticed the carb piston was occasionally a bit slow to drop, so I removed the cover and cleaned the workings with Meths, checked the needle centering and reassembled.

With respect to the Dizzy, all looked OK and all checked out well with my Avo. However, when moving the rotor I noticed some play, up and down and sideways. On removing from the car the bottom/gear end of the spindle was tight and smooth in rotation, it was the upper quadrant that moved. An internet search however pointed me in the right direction and on removing the felt plug in the centre I found the screw which hold the two halves together, it was loose.

Therefore problem was a mix of old fuel, sticky carb piston and wobbly distributor spindle!

Many thanks to all for taking the time to pass on your advice!