Car won't start after rebuilding carbs

I’m old and I’ve had my 1965 E-Type since 1966. All bodywork was restored in 1985 and since then only driven 8500 miles. In the past seven years, only 300 miles per year. Always in garage. Last winter after some cold starting problems, I decided to rebuild the carbs.

Currently, the compression is good, 175psi, on all cylinders, the distributor is new, the timing is good and the spark is reaching each plug in the correct sequence. Also, I can hear the ‘tick, tick tick’ of the fuel pump delivering fuel to the carbs.

When I try to start the car, according to the recommended manner, nothing happens. When I squirt gas into the Carbs and then try to start I get a minor explosion which stops the starter motor. I’m now scared to repeat this and I need help. In fact, when I don’t spray, the engine turns over normally but the engine just doesn’t start.

Peter

Hi Peter,
Welcome, the first thing I’d do would be to go back and double/triple check the ignition wires, I know you said in the correct sequence but you wouldn’t be the first one to have them 180 off.
Good luck,
Cheers,
LLynn
PS: all the vacuum hoses are connected right?

Hi Lynn,

Well, after connecting the vacuum hoses (thank you) I tried again. To double check the timing I used the 'cylinder 2 and 3 equal height " method to determine TDC, then checked the position of the rotor and then adjusted the advance by rotating the distributor slightly.

It still didn’t want to start. I did not use any spray, just the choke from inside the car. The starter motor turned the engine easily but after 20-30 seconds I heard noise from the engine stopping abruptly with a grating sound, probably from the starter motor. Ugh!

Peter

Peter,

Hopefully you have a manual. Getting the choke cable adjusted properly to facilitate starting is a bit fiddly and a manual is very helpful here.

You say the fuel pump is working, but have you verified fuel is reaching the carbs?

Are the carb settings (idle air bypass screw and main jet height) in the right ballpark?

Hi Steve,

Thank you for replying. The answer to your three questions is ‘yes’. I installed a new choke cable and redirected it according to Richard (posted March 2020)

I removed one of the Banjos to make sure gasoline was getting to the carbs.

I set up the carbs according to page C4 in the Green book.

Peter

I think you may need to go a step further and verify that fuel is getting into the bowls.

A stuck needle will prevent the bowls from filling. I do not have SUs but I suspect it is simple a matter of removing the top from the bowl and seeing if there is fuel in there.

Thank you, I will investigate

Agreed. But perhaps even simpler to remove the bell and see if fuel is visible in the jet…and note if it is about the right level below the bridge.

Did the “ticking” of the fuel pump eventually stop before turning over the engine?

1 Like

I have to agree with llynn. If all the ignition is correct spraying gas into the carb throat should result in the engine starting briefly and dying. There should be no explosion. You need to recheck your timing again and also verify that you are setting the timing with the correct piston at top dead centre on the power stroke. BTW. we are pretty much all old here😀

Marco, Thank you. Yes, the ticking sound stopped, as I expected

Peter,

To be clear since you’re getting suggestions about ignition and such, the car was absolutely running albeit roughly, at the time you removed the carbs for rebuild and nothing else changed in the interim?

So how many months old is that fuel and did you add fuel stabilizer?

If so then in all likelihood we need to focus on fuel, unless carburation was not the real problem you had when you decided to pull the carbs.

What did the carb rebuild include ?

Hi Geoff,
I must admit that both you a llynn are just what I thought, in the first place.

The problem is that the rotor is in the 7 o’clock position, pointing to the #6 plug, as it should be.

In addition I used the 2&3 cylinder timing process (Ray Livingston and others) to get there. If I were not on the power stroke, I’d expect the rotor would be pointing to #1 plug.

Also, I’m trying to advance the timing by using the adjustment on the distributor vacuum unit - maybe that’s wrong.

Do you have a small mirror? If so you can set the crank to TDC and peek into the oil fill hole to see if the front cam lobes point out and the notch faces up. If not the then crank has to go over a full turn to get you where you need to be. In this position the rotor points to 6.

Checking piston position alone doesn’t help much since it’s going over twice for each rotation of the cams.

Which cylinder are you calling #1? The #1 cylinder on an xk engine is the one closest to the firewall

Hi Geoff
Yes I understand, and # 6 is at the front of the engine
Peter

Ok , then if timed correctly your #1 piston should be at top dead centre, your pointer should be pointing to the timing mark on the harmonic balancer and your rotor should be pointing to just before the wire that goes to # 1 sparkplug. I understood you to say that the rotor was pointing to #6. which would indicate that it is timed 180 degrees out. Did I misunderstand what you wrote.

That is true if #1 is at TDC on the compression stroke. Though I generally work timing with #6 on compression stroke since (as Erica pointed out) you can visually confirm that by peeking into the oil fill opening and looking at the cam.

But Peter - have you confirmed that the carb (not just the bowl) is getting fuel? I mentioned opening the bowl and removing the dashpot and looking down at the jet was suggested. If the plenum is off you can even look into the throat of the carb where you should be able to see fuel as the engine is cranked.

If everyone is satisfied that the car is timed correctly I will concede, however a minor explosion that stops the engine from turning over red flags ignition timing to me. If it is truly a lack of fuel after a carb rebuild one thing to check is that the overflow tube washers are correctly installed to allow the fuel bowl to vent properly.