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My understanding is that the k-jet Air/fuel mixture adjustment for my ‘78 requires a longer-than-normal hex wrench. What’s the minimum acceptable length for the tool to work without removing the air box? 9”? 12”?
Also, is it necessary for the end of the hex to be a ball hex or is a traditional end acceptable?
Looking in the K-Jet workshop manual, it has the part number for the 911/924, but the 928 is just specified as "manufacturer tool", which is oh so helpful.
It does state that it should be a ball-end wrench, though.
Yeah MrMerlin and I were chatting at the Rendezvous 928 event and he mentioned that the regular 6” version won’t work unless you modify the handle to make it longer. I found a 9” version on amazon with a ball end for <$10 so I’ll try that.
The one I have has a screwdriver handle rather than the T, and a flex section just above the hex. Had it since the late 1970's so can't point to a source. It does not have a ball end.
Reminder that you MUST remove the tool after adjusting, before you ref the engine. Else the tool or the arm will get bent.
If the airbox is out of the way, any 3mm hex will work. My setup is non-standard so I don't know how long an adjusting wrench you'd need leaving the stock airbox in place, but the info provided by others below should provide that.
To understand how it works, this assembly has a 3mm hex in the top. When you put your wrench into it and push down to compress the spring, the other end under the plate actually mates with the real 3mm hex mixture adjustment screw, where turning the top section then turns the mixture screw. The spring puts upward pressure on the o-ring at the base when your not adjusting to seal the adjusting mechanism to the shoe so you don't have a vacuum leak. The bottom of the extension piece often gets worn and then doesn't engage well with the mixture screw. In that case you might need to remove the assembly and grind off a little of the bottom piece to get a clean engagement again.
My understanding is that the k-jet Air/fuel mixture adjustment for my ‘78 requires a longer-than-normal hex wrench. What’s the minimum acceptable length for the tool to work without removing the air box? 9”? 12”?
Also, is it necessary for the end of the hex to be a ball hex or is a traditional end acceptable?
Application: Porsche® 928 78-84 K-Jetronic (CIS) and L-Jetronic
This is the perfect tool to adjust the air/fuel ratio (also referred to as CO in the manual) on the 928. For both K-Jetronic and L-Jetronic equipped cars.
ItemPart NumberPrice(USD)Shipping*Availability
Standard Air/Fuel Adjustment Tool for the Porsche® 928TOL-AFAT$14.20U.S. Only: $8.00
All Others:
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07-01-2019, 02:47 PM
CIS K-Jet Air/Fuel hex tool
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