Carbs not feeding same amount of fuel

[skrillac]

I recently rebuilt both of my carbs for a 96 GTI with the OSDMarine kit that specifies no need to set popoff pressure (return to OEM kit i believe). At the time I rebuilt my carbs I thoroughly went through and cleaned everything. Yesterday, I started the engine fine by pouring a splash of gas into both carbs. Ski kept idle at a decent spot, was a little high. At this point I added the manifold back on and arrestor screen and was able to start the ski without pouring more gas into the carb throats. I didn't finish setting the idle speed yesterday, so I went back today to adjust it further. Was able to get it to start once, but the ski died a few minutes after starting, at low rpm. I did notice after it died that the pto side carb was emitting vapor from the throat, upon removing the arrestor to see better in there.

I went ahead and shot the below video to describe the current operation better. The orientation of the camera shows the left carb (pto side) and right carb (mag side). The right carb has presumably no issue feeding gas into the cylinder. The left carb, however seems to have difficulty. With the arrestor screen installed, after spinning the engine and removing the arrestor screen i can see that both carb throats are soaked with gas.

I'm not sure if either of these carbs are putting out what they should. Is this something I can adjust with screws or am I looking at opening these carbs up again?

 

[mikidymac]

You should not have fuel blowing back out of the carb.
Compression?
Rotary timing?

Or leaking needle and seat letting way too much fuel out.

 

[skrillac]

I recently rebuilt the top end of the engine. From my reading a few weeks ago it reads 135lbs of pressure on both cylinders. I can only assume the rings haven't seated yet. I also replaced the rotary wheel and cover. Timed it properly according to the manual with a degree wheel.

The back to oem carb kit from osd came with replacements for everything, including needles and seats. Anything that could come out of those carbs did. I guess i need to manually set pop off pressure. Can't think of anything else it could be.

 

[skrillac]

@mikidymac

Does it look like to you that the right carb (mag side) has a leaky seat and the left carb (pto side) has too high pop off pressure?

 

[skrillac]

So the mag side carburetor retainer was loose, which caused a leaky needle. I just tightened that retainer screw. After I tested both carbs pop off. Measured roughly 40-42 psi on both carbs. Manual says that is nominal for 96 gti.

I'll retime the injection pump tomorrow and see if my starting issue goes away.

I'm not sure why this would affect the pto carb though. Unless the pump wasn't actually pumping through the pto carb because of the leaky needle in the mag carb.