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I finished assembling my old Skoda Estelle engine, fully tighten, valves calibrated, etc. It turns, a bit "tight" i.e, not "loose" like before but it may be because I put new rings and different liners. It turns but it won't start. I didn't mess with the timing, so it is set exactly as it was running. I see spark in the coil, spark in the wires and spark in the plugs. I see the carburetor jetting gas, but still won't start. No gas smell neither. One thing I noticed is that the spark plugs are not getting wet in gas. I tried with the choke a few times, didn't start and the spark remains dry. When choking and gassing for long time, the spark should be wet.

So any ideas??

More:

After a few (almost a lot) of cranking :) the sparks should have at least a gas moist, they should smell to gas, but they don't, they are completely dry. Choking the carb will make the sparks even more wet, but nada. So no fuel seems to get in. Then I took the carb off the manifold, I see it jets down gas when moving the trigger. In the carb seat in the manifold, there are two entries, one is like a bottle cap upside down, there I see some gas deposited, not "much" but some. In general, no gas or fumes smell whatsoever. I will try feeding the carb directly (hose and bottle instead from the gas pump, we call it a "serum" :) ), after I disassemble and put it back, just to be sure it is clean. It shouldn't be dirty, it was working ok, but only God knows :)

On the other hand, when I rebuilt the gas pump I see it was clogged with soil everywhere and barely pumping. So I re-did it and it pumps now like new. When I installed it I could prime it nicely, gas went up to the carb in no time, but after the cranking sessions, I still could prime it manually anytime. It shouldn't, right? Since sometimes the camshaft should be in the pumping position, so the manual primer lever can't move more, since the pump shaft is already pushed by the camshaft. I can move its manual primer any time, so seems to me maybe the camshaft is not moving the pump, then no gas up to the carb. I had to fabricate the Bakelite spacer, since it got a piece of rubber pad instead. Maybe the thickness is too much, but I left it about 5mm thick. However I don't see the line getting dry, no air bubbles...acts more like the carb is already filled up and no more gas gets in. Definitely "maybe" the carb/engine not sucking enough?

I hope I'm not having to uncap the engine again :(

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3 Answers 3

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ok a few things to check then

  • do you have enough compression?
  • are you cranking fast enough
  • you should be able to smell fuel as your cranking. take any filters or intake off and smell what happens. my guess is you are either too right or too lean
  • also your fuel is good fuel I am assuming.
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    The only suspicious thing from your list is that the battery got so-so, and it is turning not so ok that we could say :) I already put it to charge. Enough compression: need to check, but have no means. Fuel smell: I have no air filter over the carb yet. The carb is adjusted as it was, never touched that. I don't smell any gas. I see a very small gas puddle under the carb inside the intake manfold, but the sparks are dry. The engine doesn't even try to start. I see the carb jetting, but maybe it then gets depleted of gas?
    – Aram Alvarez
    Commented Nov 17, 2016 at 2:44
  • @AramAlvarez You sure you're not flooding it and what is meant by sparks are dry? as in no fuel in the cylinders or no fire? and the small puddle meaning if you open the carbs butterflies you can see gas inside the intake manifold or is there gas leaking underneath the manifold. If there is puddles inside the manifold then you might be flooded. wait till it evaporates. Also the carb bowl is full and gas is getting to the carb right? you don't smell any gas from where?
    – Cc Dd
    Commented Nov 17, 2016 at 3:52
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Assuming the engine is getting fuel.. You need to do a compression check. This will help guide you in the right direction.. As perhaps the valve timing is way out, or the vales are not closing properly etc.

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    I did a valve job on the head, did a leak test that first failed but after some valves twists with the hands the test were ok (I guess first failed because debris). I will try to fabricate a compression tester, lets see what it reads.
    – Aram Alvarez
    Commented Nov 17, 2016 at 5:30
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did you try a shot of starter fluid into the intake to see if she will at least fire over once? My guess based on your description is your carburetor accelerator pump is not pumping fuel. All of this is based though on that you did not disturb the timing for the valve train. I'm sure your aware that the crank shaft and the cam shaft must be in perfect timing alignment and the cam be in the power stroke of the designed first cylinder. most often this is #1 in the firing order.

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