Stumped..

2 cyls on same carb?
Plugs look good? (2 not firing washed down?)
I'm sure you've checked the firing order a zillion times, so I won't insult you by mentioning that.
Strange.

 

Try some carb cleaner sprayed into the throats of the cylinders that won't fire. I suspect that there is no fuel in those cylinders, and spark is ok.
Doesn't take much to clog a main jet/Idle circut.
Does drying the plugs (if they are wet) off help it run on all four-even for a short time?

Good luck

E

 

Lagerlout,

Sorry to here of your difficulty. I have an S2 Elan with DCOE 18's too.

The twink with Webers is prone to flooding at startup, so check the condition of the plugs. Are any of them wet with fuel?

Your engine uses the same plugs as 308's. The Lotus baseline plug is too cold for normal operation. Try some new plugs with a modest gap of maybe 0.025 inches. NGK BP6ES or better yet BP5ES, or their equivalent, would be a good choice. Change them if they are wet.

There are lots of possibilities for trouble shooting, but best to retrace some of your steps.

1. Are you sure timing was set on number 1 on the compression stroke?

2. To static time, I always set the engine up at the point of firing, then turn the distributor base in the correct direction until I hear the ignition fire. The correct direction to turn the base is opposite to the rotor direction. That is, back off the distributor in the retard direction, then advance it relative to the rotor until you hear the ignition fire, it'll sound like a click. 12-degrees BTDC is a little agressive in my opinion given your current difficulties, try setting it to 8-BTDC until you get it to fire and clear itself. This should make cranking a little easier too. Ensure your battery is up to snuff. Charge it well and check the fluid level.

3. Check that the plug wires are on corrrectly. Firing order is 1-3-4-2. Check plug wire electrical resistance, cap to plug end. You could have an open.

4. The floats on DCOE 18's sometimes hang up. Check for freedom of movement. With the cover held vertically, float level is 8.5 mm between cover, with gasket fitted, and the float. The float tang should be lightly sitting on the valve ball, but not depressing it. Droop clearance is 15mm, again with the gasket fitted. Too much droop could cause the floats to hang up.

5. Pull the starting and idle jets and blow clean with compressed air or at least carefully inspect. Sometimes debrit will find its way in, especially if a fuel filter is not fitted. You don't know what might have been in your new fuel tank. Check that the fine mesh screens are fitted at the inlet and are clear.

6. Check and record the existing mixture needle valve positions by lighting seating. A good initial setting would be about 3.5 turns open.

7. Perform a crude idle synchronization check by removing the brass screw caps covering the progression holes. With a light, you will be able to view the relationship between the throttle plates and the progression holes. All holes should be covered with one set just beginning to be uncovered when on the idle idle stops. Gently actuate the throttle linkage and confirm that all the throttle plates move in unison and uncover the progression holes by the same amount. Check that the progression holes are drilled uniformly position wise. One of my holes was miss drilled and required a small champher on the throttle plate edge to resynch it with is cousins in other bores. Replace the caps.

8. The crank pulley may have been replaced by a previous owner. There is no guarantee that the TDC mark is correct. Reestablish TDC with a dial indicator if possible. Best readings are taken with the piston about half way up the bore, from each direction, and then splitting the circumfrencial difference on the crank pulley edge.

I hope this helps.

Bill

 

Lagerlout,

Nice going. Looks like I was a little too slow to be of much help with my reply.

Bill

 

Neil,

Technical feedback on this forum is quite good in all respects. For Elan specific issues, there are a couple of other forums you may also want to visit:

http://www.lotuselan.net/

http://autos.groups.yahoo.com/group/lotuselan/

Bill