Need Help From The Carby Guys

[gtnickk]

Hey guys

 

Long time member don't get on here much. Intend to change that now i have more time now to do the finer things in life like work on old Toyota's.

 

My Problem

I have a ke55 running a 5k, trying to get a 40 mm DCOE Carb running correctly, i can get the car to fire and run, the car bogs down and does not pull. I have checked the plugs they are wet. I get the feeling the carburettor is pushing to much fuel threw. Turn Car of i here a pinging sound, bit of research has lead me to believe this could be pre detonation, so i have replaced the plugs and leads to try and eliminate that problem i have held a hose to my ear checked the manifold to see if any air is being sucked in. so there appears to be no leaks. I have also spayed some carby cleaner around the manifold to see if can get the car to increase revs, no luck thus i don't think i have a manifold leak.

 

per the weber manual i have the idle mixture screws not 1/2 turn out from being seated,

 

My car does have a mild cam, but functioned fine with a 32/36 Webber carb

 

So any ideas what could be causing this problem perhaps stuck needle and seat, do you think i need to advance the timing etc:

wrong jet size if so what would be a good size. I don't have any experience with Dcoe Carbs

 

Any feedback would be great.

 

Cheers Nick

[altezzaclub]

Turn Car of i here a pinging sound, bit of research has lead me to believe this could be pre detonation,

Set the timing first.. (before you bought plugs and leads..) 8-10deg should be fine. Set it without the vacuum advance hose on, then check that connecting the vac hose does alter the timing above idle. If it is on 8deg now, the problem is probably carb related.

 

the car bogs down and does not pull. I have checked the plugs they are wet.

Google will tell you how to check the float level, you take the top off, hold it on its side and measure how far the float is from the top.

 

DCOEs run on a low fuel pressure so you might need a fuel pressure restrictor. I bought one for about $50 for the SU carbs (they need low pressure too) and I can run it on 1psi quite happily. You could rig up a gravity feed from a jar to the inlet and see if that makes a difference.

 

The last problem might be the jetting. You'd need to research the various jet sizes for a 1.5L with a single DCOE to get in the general ball park, the final jets would differ according to cam etc. All much easier with a mixture meter, so either pay some garage/dyno guy to check the fuel mixture as the motor works, or buy a fuel mixture display gauge & an oxy sensor.

 

Check the timing and float level, then whip out the jets and post the statistics up on here, someone might have a good idea what you need. You'll have main fuel jet, main air corrector, emulsion tube, and then the same for the idle circuit. There will also be the 'choke' diameter in the throat. The DCOE idle circut is not like other carbs where it just restricts the amount of air going in, the DCOE idle runs the motor up to about 2000rpm before handing over to the main circuit.

 

perhaps stuck needle and seat

 

Sorry, forgot that bit- yes, make sure the needle and seat are clean with no tiny fibre lying across them.

Edited May 7, 2014 by altezzaclub

[altezzaclub]

here- check out the pink options. See what's in your carb as a comparison.