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Posted by: lmcchesney Jul 15 2006, 08:30 PM

I can't remember how to adjust the idle speed on my D-jet. Is it done by the air bypass valve? or does this just adjust the mixture of idle speed?
I cannot find another adjustment screw on the throtle body. What am I forgetting?
Thanks,
Larry

Posted by: 914-8 Jul 15 2006, 09:35 PM

it's the adjustment screw on the throttle body. works by simply bypassing air.

Posted by: lmcchesney Jul 16 2006, 08:10 AM

Got it.
If you adjust the idle speed with the bypass valve, how does the ECU mixture valve adjust mixture (quanity of air vs fuel)?
Thanks,
Larry

Posted by: 914-8 Jul 16 2006, 08:18 AM

The manifold pressure sensor does it.

Posted by: lmcchesney Jul 16 2006, 05:40 PM

OK. I adjusted the air bypass screw on the TB and got the idle down to 1000rpm but runs rough. CO meter at 1.7 or about 14.0:1 A/F ratio. I enrich with the ECU adjustment to a CO of 2.3 or about 13.8:1. Is this the correct CO A/F setting?
Another thing, the engine is a 94mmx78mm stroker with a web cam 73 on D-jet.

Thanks,
Larry

Posted by: bd1308 Jul 16 2006, 07:21 PM

apparently so....the stock CO emissions standard was around 2%

13.8 under load is lean, but at idle, id want it closer to 12 or so like it should be when going...

b

Posted by: Cap'n Krusty Jul 16 2006, 07:54 PM

QUOTE(lmcchesney @ Jul 16 2006, 04:40 PM)

Posted by: lmcchesney Jul 16 2006, 08:35 PM

Thanks Cap'n,
I do not have an HC monitor/meter.
Larry

Posted by: Bleyseng Jul 17 2006, 08:52 AM

and whats your idle vacuum on a vacuum gauge? probably around 12-13hg at idle instead of stock 15hg. Its tough to get a good idle running a web73. Don't try to run the idle at 950rpms bump it up to 1100rpms and it should smooth out.

Posted by: lmcchesney Jul 17 2006, 11:11 AM

Thanks everyone.
Anyone have a suggestion for the timming?
I have a 0degree but not the 5 or 27 degree marking.
Larry

Posted by: Bleyseng Jul 17 2006, 11:19 AM

look at the Pelican Parts article for the little pic of the timing marks and mark the fan for 27 degrees BTDC. Then time it with a lite.

Posted by: lmcchesney Jul 17 2006, 02:19 PM

Thanks all.
Read the bird article. Cut out the templet. Marked the 27degree spot, boy, was that fun for my son and I. Lesson in vocabulary.
Warm engine, both vac/advance hoses disconnected from the distributor and plugged. Timed at 3500rpm at 27degree BTDC. Adjusted the Idle to 1100rpm. Will check the CO output and adjust the ECU idle set.
Now for the partial and WOT adjustments.
Thanks again.
Larry

Posted by: Bleyseng Jul 17 2006, 06:17 PM

Larry, check your PM's for MPS details.