Difficulty Starting GT6 MK3 - Stromberg CDSE150's

[sam93]

Running last year well. Couldn't tune correctly as choke was on when off and vise versa. Fitted new cold start valve, now can't get it to start, unless someone simulates a manual choke by covering a proportion of the air inlets with their hands. Once started runs strongly but need to keep revs up or it dies. Got a good spark at each plug. After multiple starting attempts, the plugs smell faintly of fuel but are not wet with fuel. So I don't think it's getting enough fuel. Carbs have been fully rebuilt including new jets and needles. Manifold studs replaced, new gaskets & no air leaks present. Needles set fully rich choke also works as it should. At full choke only the first two holes on the cold start disc line up with the passageway on the carb. So to compensate I've enlarged the holes to allow more fuel through, which I believe to be equal to more rotation of the disc.

What on the engine / cylinder head would you check first. Going to have a compression tester by the end of the week, so I'll get some figures up after. I've read that a cold compression test will not prove an awful lot ?

Tried to summarize as best as possible. Need any more info let me know. I'm at a complete loss as to why it won't start. I bet it's something really simple which I've overlooked.

[don cook1]

If I remember correctly its not obvious how the cold start valve fits. It was a while back but I fitted mine wrongly and mine wouldn't start. Its all to do with getting the myriad of slots in the correct position.

[DougBGT6]

Have you got the carb to manifold gaskets on right? They can go on 4 ways only one of them right, obviously  ;D. I got them on and off three times before I cottoned on.  :B

Compression test. Mine are all around 150 but less is OK, more important that they should all be within 10/20 of each other.

[sam93]

DougBGT6,

Can you elaborate on the topic of the gaskets ? I didn't have any additional holes to line up on the manifold when I fitted the carbs.