'75 L28, fresh rebuild, wont start.

1. Ive got spark

2. Ive got Fuel

3. If I remove the hose going to the mechanical fuel pump outlet, and spray air through the hose towards the carbs, with the throttle open, fuel comes out from the carbs. I can then start the car for about 10 seconds, then it dies.

4. It will run off of starting fluid.

Any ideas?

If it'll run off starting fluid then it's a fuel issue.

If the fuel pump can provide enough flow, than the problem downstream of the fuel pump.

Time to look at the carbs, sounds like.

What carbs are you running?

If it'll run off starting fluid then it's a fuel issue.

If the fuel pump can provide enough flow, than the problem downstream of the fuel pump.

Time to look at the carbs, sounds like.

What carbs are you running?

dual round top SU's.

What am I looking at here?

Test the fuel pump for output. If that is good then look at the floats and float valves and the fuel filter built into the top of the float bowl cover. Also, check the hoses at the botton the carbs to make sure they are not pinched or blocked.

First check the fuel pressure. Pull the outlet line & crank the engine over. It should squirt a fuel a couple of inches, once for every engine revolution. Check the fuel filters in the banjo fittings on the f-bowl tops. Turn the mixture screws all the way up & count the turns. 2 1/2 is about normal. If these are considerably different it is an indication that the float level is wrong. A quick search of "Quick & dirty carb tuning" will get you the details you will need.The best info I've found is from ZCarTherapy. They have a DVD on just SU carbs that explains all you need to know.

I just had that issue on a '73 that I recently bought, with '72 carbs. It also would start with some brake cleaner shot into the carbs but would not run. In my case, the nozzles were not dropping properly when I pulled the choke lever. After refurbing the SU's and adjusting them (and making sure the nozzles were not sticking) the car starts and runs fine.

Edited May 8, 201410 yr by tlorber