Time of day to tune SUs?

[Jehannum]

Fixed the misfire - turns out that if you don't start the car for a year, the points can get a little crusty. I haven't been able to take it out to see if I fixed the backfire too.

The carbs were fine - float levels were appropriate, the pistons may have been a touch low, but I fixed it up with some 3-in-1.

[Travel'n Man]

I'm dizzy from reading.............too many beers........I've got to re-read.........

Edited May 22, 2010 by Travel'n Man

[Gary in NJ]

To the OP, glad you got it worked out.

To epsark, 12-hour shifts makes you wanna type I guess

The SU floats are solid. They should last a lifetime and a half - unless you use carb cleaner on them - then they swell. Setting/checking the floats should be an annual procedure.

Reading your post it sounded like you had a high float, until you mentioned plugging one vent transferred the overflow to the other carb. Yes, you might have too much pressure on the fuel line - or the return is clogged.

[beandip]

epsark, take a close look at the end of the fuel rail where it goes from metal to the rubber then back to the tank. The end of the metal rail is closed , but for a small metered hole. I this is plugged you may have found the problem. I am running a RX-7 electric pump only and it puts out between 4&5 psi . Steve , the owner of ZTherapy told be that this is ok but at the upper limit of pressure. I have been using this setup for 9 years or so and no problems. In any event it sounds like the pressure is overwhelming the needle and seat of the floats.

Gary

[epsark]

To epsark, 12-hour shifts makes you wanna type I guess

With the work I do it is usually feast or famine and tonight seems to be famine. That and I have been thinking of this problem since it cropped up on me and I haven't been able to quit. Guess that's the technician in me.

take a close look at the end of the fuel rail where it goes from metal to the rubber then back to the tank. The end of the metal rail is closed , but for a small metered hole. I this is plugged you may have found the problem. I am running a RX-7 electric pump only and it puts out between 4&5 psi . Steve , the owner of ZTherapy told be that this is ok but at the upper limit of pressure.

This was one of the things on my lsit to look into. I just didn't realize that the end of the rail was a small metered hole. Sounds like this may be where my problem is. I still plan on adding the regulator as a way of ensuring that I don't get too much pressure down the road. Any idea how big the end of the rail is supposed to be? That way I have an idea of what tools to bring from home instead of everything. May even have the correct things in my tool bag here at work.

[epsark]

Here is an update for anyone interested. I checked the returne line and nothing was blocked so that was ruled out. Next I took the float bowl lids home and cleaned those and made sure everything moved freely. Installed those again and started it up and at first it was working well, then the engine hiccupped due to it being slightly cool yet and started geysering out the fron carb again. Went ahead and installed a pressure regulator and a new glass filter there in the front. While I was at it I took the float lids off again and decided to adjust the height of the tab that controls the needle valve up so it would close more, on both. BTW, when you have the float parallel to the top of the lid, how do you know the needle is closed? Is it when there is no more upward travel to the needle? Anyway, put it back together and turned just the fuel pump on. No leak. Fired up the engine and purred away. Revved it a number of times, no leak. Checked the pressure and set it so that it doesn't go any higher than 4 PSI. Everything seemed normal, so took it for a quick spin and all is fine! Yeah!! I have my car back!!

[Gary in NJ]

Sounds like it was a stuck grosse valve. Good thing you caught and repaired that. That can be a fire hazard.