Cannot sync with new carbs
in 912 / 914 Technical Questions
5 years ago
I have now tried three different sets of carbs including a new set on this under 100hr 912 and The same behavior with all of them when trying to pneumatic sync.
Left side makes good vac at idle but right side is will not. To get them close, throttle positions are very far apart. (3/16”+) And egt’s are then very far apart as well so that feels like a bandaid.
Direct Compression test shows 135psi on cyl 1 and 2
155psi on cyl 3 and 4
Diff compression test shows all within 2 psi. 82/85 etc.
I have done the intake leak test spraying starting fluid while at idle and no change in rpm.
New plugs, Also dee no change in right/left relationship during mag check.
I have replaced fuel lines and blown out banjo Tee fitting.
I have removed valve covers to confirm that all valve are opening completely and no rocker play is present at any point.
I am now 2 months in trying to find the issue with no resolve.
Please help.
Is there any possible ignition issue that could effect right/left?
They will not sync and the egt’s are 350 set apart in cruise rpm.
Engine does not run rough though.
Left side makes good vac at idle but right side is will not. To get them close, throttle positions are very far apart. (3/16”+) And egt’s are then very far apart as well so that feels like a bandaid.
Direct Compression test shows 135psi on cyl 1 and 2
155psi on cyl 3 and 4
Diff compression test shows all within 2 psi. 82/85 etc.
I have done the intake leak test spraying starting fluid while at idle and no change in rpm.
New plugs, Also dee no change in right/left relationship during mag check.
I have replaced fuel lines and blown out banjo Tee fitting.
I have removed valve covers to confirm that all valve are opening completely and no rocker play is present at any point.
I am now 2 months in trying to find the issue with no resolve.
Please help.
Is there any possible ignition issue that could effect right/left?
They will not sync and the egt’s are 350 set apart in cruise rpm.
Engine does not run rough though.
