Carbs

[Barry20383]

The engine is dead
Have checked the spark at no1 cylinder with a spark gap tester it is easily jumping 10mm.
Have checked plug leads for firing order it is correct
Have turned engine over by hand till no 1 cylinder gets a spark and then checked the push rods both are free to rotate seems timing is correct.
Compression on all cylinders is showing 140psi.
Have put small amount of fuel down each carb still no response.
Pumping fuel pump by hand i can hear
fuel entering bowls and pump is cutting off when full.
Am still wondering if its the bowl fuel levels too low and the cylinder vacuum cannot pull the fuel out from the emulsion block but pouring fuel down the carbs should have solved this problem. I was wondering as the carbs are re con if something is wrong with them as one gasket fault already cleared whatever it is its common to both sides of the engine if only one carb was working i would think cylinders on that side would fire.

[Keith Clements]

If you suspect the carb then change back to one old one, firstly the bowl as there is not much in the body which can go wrong unless they have been soda blasted to be cleaned.

It has fired on those carbs, so possibly one of the jets or passageways has blocked.

Even so it should fire with a little petrol down its throat.

Just a thought are they correct reach and temperature spark plugs?

[Barry20383]

The re con carbs have been cleaned and are shiny inside and out what they have been cleaned with i don't know i bought them from the Jowett Spares Paul Beaumont

The plugs fitted are NGK B6HS and gapped at 25thou and are new.
.

[Keith Clements]

Are the filters fitted in the banjo inlets to the carbs?
I know you have a plastic filter, but just maybe that has too high a resistance for the pump.
Still would not stop it starting but it might allow only a bit of fuel to go through. You can test to see how quickly it pumps a litre but if it continuously squirting then that should be good enough.
As I said before I would use Easystart just to make sure the engine is firing.
If it does not fire on that then it is more than likely ignition related. You could try a wider spark plug gap say 35 thou.
If it fires but does not run then it is more than likely petrol related as your compression seems OK, unless the ignition or valve timing is way out.
If it runs but is lumpy then it could be distributor, leads or mixture.

This was a running car before you started, so you have to eliminate everything you know you have done and anything you might have done.
Did you swap the bowls like I suggested?

[Barry20383]

Will change the bowls over and give it a try.
I cleaned the banjo fuel filters when i fitted the carbs.
The plastic fuel filter always seems to have air in it perhaps i can take it out for now as its none original
I have obtained some quick start will give that a try as well..

[Barry20383]

Have taken the bowls off they are full of fuel and the floats working ok not sinking. Fitted the old bowls and tried engine still no response
Checked spark with spark gap it is jumping 12 mm At the plug cap.
Have turned the engine over by hand till the timing marks on the front cover and pulley align Checked the marks on the fly wheel the single line is in the middle of the hole with a dot each side. Removed the dizzy cap and rotor arm is facing no1 plug cable. Number one cylinder push rods rotating free. Is this the way to check mech timing.
I put quick start down both carbs and tried to start engine still no response.

[Keith Clements]

Barry,
Seems the correct procedure but as a check I put a length of thin plastic wire down the spark plug hole and bring slowly to TDC just to make sure the timing marks on flywheel and pulley are correct.
I also check that the NO 1 inlet just starts to open at the 12 deg mark on the flywheel to give a rough check on valve timing. You need a dial micrometer to do it properly.
Then with No 1 spark plug resting on the head check the spark comes exactly at TDC. Do it a few times to double check.
Then make sure when this happens both push rods on No1 spin.
Then do the same on all three other cylinders.

The only thing left on ignition is a worn distributor which might give too much advance at cranking speed. You mighty be able to see this with a strobe but it would be difficult. As a test just retard the ignition by 5 deg.

If the above is all OK and you have changed both bowls to the originals then all I can suggest is to change both carbs back to original. The body mighty have an issue introduced by the recon.
Failing that not working we can probably get a pair of known working carbs to you.

I find it amazing that there was not even one cylinder firing with Easystart. I open choke and throttle fully, squirt in Easystart then with throttle half open hit the starter.

[Barry20383]

Will do as you say thanks for the advice will get back with results.

[Barry20383]

I was wondering as the car stood outside and not used for a long time weather when the engine started the bob weights in the dizzy stuck out would this be enough to put the timing out enough to stop it starting will check the dizzy. Would think if it fired before a valve closed it would blow back either carb or exhaust but getting nothing.
Tried again with your method of easy start with good spark had no response.
The easy start is drawn direct into the cylinders bypassing the carbs perhaps the carbs are not the problem.
I have a strobe light was wondering if this can be used with the starter motor to check timing of spark.
Thanks Barry.

[nigel jarrett]

Hi Barry,just a few thoughts ,check the distributor cap for cracks and tracking .Put an extra earth between the distributor and engine case .Check the resistance of the plug leads between the terminal in the plug cap and terminal inside the distributor cap ,perhaps replace the low tension lead between the coil and distributor.Chech for air leaks between fuel pump body and lid .Disconnect the fuel filter and check the fuel delivery when cranking on the starter.
A trick I was taught years ago to test the rotor arm is to take off the distributor cap leave the rotor arm in place ,disconnect the coil lead from the cap ,make sure the points are closed .With the ign switched on ,using insulated pliers hold the coil lead close to the rotor arm but not touching then flick the points open and closed ,if you get a spark the rotor arm is shorting and faulty .
Good luck and hope you can get to the bottom of the problem.

[alexander]

Hi Barry
After cranking the engine over are the plugs wet, if not I would check the fuel side again
Dave

[Forumadmin]

It is good to see more input on this subject. Hopefully more investigation will uncover the reason...or perhaps the delinquent Jowett will just fire up one day and run smoothly.
Bear in mind that Barry does say he is getting a good spark. So it is unlikely, but I agree still possible, that the there is a tracking problem.
Also that the use of Easystart should exclude any carburation issues, but once again not completely, as the plugs may get wet through petrol pouring in. So dry plugs by heating and try to start on Easystart before anything else.
Yes there could be a distributor issue with weights or capacitor or earth wires which would give a spark but not at the right time. I have the benefit of always having a known working dizzie on hand.
I have found many dizzies on Jowetts with wear that need the static timing altered for the car to start.
It is all too easy to get the ignition leads mixed up so double check the spark is at the correct cylinder at the correct time.

[Barry20383]

Good news have managed to start the car.
I used Nigels method of checking the rotor arm and turned the dizzy cap upside down and put the coil lead next to each post then opened the points got a spark each time through the plug. Put the no1 cylinder at tdc and put the coil lead to that post when spark came the no1 cylinder kicked. Ignition all seemed ok.
Then checked fuel pump took of the carb supply pipe and turned engine over seemed good flow but with lots of air bubbles making fuel white. Took off the added fuel filter and made a new flexible fuel pipe to leave out the fuel filter. Tried engine and it started on choke a bit lumpy but needs adjustment which is to be expected with adding new carbs. Timing chain is a bit noisy will read up how to use the tension bolt.
Hope its ok now as i can carry on next job change engine oil and filter. Thanks everyone for advice and help.

[Keith Clements]

So the problem was the plastic fuel filter aereating fuel?
Poor joints?
Or is there a leak in the fuel pump diaphragm?


Did you not already check you had a spark on all four cylinders at the end of their compression stroke so why check the rotor arm?

Does it now reliably start when cold and when hot?

Put your strobe in circuit and check advance curve with and without vacuum advance.

Check colour of plugs.

There is no timing chain tension bolt on any Javelin I have seen. If you are talking about the camshaft end float adjuster then do not loosen when running!!!

[Barry20383]

I checked the rotor arm as Nigel suggested i had fitted a new one but was ready to try anything.
The fuel filter was always full of air and the fuel coming out was full of air bubbles. Don't know if this was the problem but it started after being taken out.
I saw articles of people fitting a timing chain tensioner and i thought mine had one must be the cam shaft adjuster so will leave it alone.
If the engine is now ok i have to set up the carbs i have a flow meter to set the balance