Brain fart question 914-6 Options

[mb911]

So I am helping a member put brakes on his 914-6 conversion and then put carbs on it. He previously has a poor working sniper setup. It ran ok prior according to him. Then they switched to a 123 dizzy and removed the MSD ignition and then took to a tuner prior to my part. It ran much worse once the 123/MSD removal. The owner decided he was done with his sniper setup and asked me to put carbs on. I did that and for the life of me we can’t get it to run right. Starts pretty easy and idles decent. When I go to throttle up by hand on the cross bar it doesn’t want to accept all the fuel and shoots quite a bit back up through the horns. My suspicion is a major timing issue as in 180 off. The carbs are new and setup up by Dave Chenny so very confident in them. Seeing as the car is 1.5 hours away each visit I am looking for a bit coaching here. What else should I be looking at? The engine is a fresh 2.7 not built by me with about 1000 miles on it.

Help with some ideas please.

[Retroracer]

So I am helping ...The owner decided he was done with his sniper setup and asked me to put carbs on. I did that and for the life of me we can’t get it to run right. Starts pretty easy and idles decent. When I go to throttle up by hand on the cross bar it doesn’t want to accept all the fuel and shoots quite a bit back up through the horns. My suspicion is a major timing issue as in 180 off. The carbs are new and setup up by Dave Chenny so very confident in them. Seeing as the car is 1.5 hours away each visit I am looking for a bit coaching here. What else should I be looking at? The engine is a fresh 2.7 not built by me with about 1000 miles on it.

Help with some ideas please.

Ben - you don't state what fuel pressure / pump / regulator set up the car is running. Presumably (I've never used one, but) the sniper EFI needed a much higher fuel pressure feed than the carbs (probs at least 45 PSI or higher) - did you somehow reduce this to <5psi for the carbs? If not, likely the floats are probably being overwhelmed at idle and too much fuel is sloshing in.

Also: if Dave C rebuilt the carbs I'm guessing they are Zeniths - so will require 3.5 - 4.5 PSI for decent running. Hopefully he bored out the Venturis and rejetted for the 2.7 too...

Hope the above is useful,

- Tony

[mb911]

So I am helping ...The owner decided he was done with his sniper setup and asked me to put carbs on. I did that and for the life of me we can’t get it to run right. Starts pretty easy and idles decent. When I go to throttle up by hand on the cross bar it doesn’t want to accept all the fuel and shoots quite a bit back up through the horns. My suspicion is a major timing issue as in 180 off. The carbs are new and setup up by Dave Chenny so very confident in them. Seeing as the car is 1.5 hours away each visit I am looking for a bit coaching here. What else should I be looking at? The engine is a fresh 2.7 not built by me with about 1000 miles on it.

Help with some ideas please.

Ben - you don't state what fuel pressure / pump / regulator set up the car is running. Presumably (I've never used one, but) the sniper EFI needed a much higher fuel pressure feed than the carbs (probs at least 45 PSI or higher) - did you somehow reduce this to <5psi for the carbs? If not, likely the floats are probably being overwhelmed at idle and too much fuel is sloshing in.

Also: if Dave C rebuilt the carbs I'm guessing they are Zeniths - so will require 3.5 - 4.5 PSI for decent running. Hopefully he bored out the Venturis and rejetted for the 2.7 too...

Hope the above is useful,

- Tony

Running 3 psi with PMO regulator


As for wideband 02 no this car is so far away from requiring this and definitely is not lean the plugs are pure black