SX200TXRC Fuel Issue

Bensarro

Recruit
Joined
Nov 20, 2018
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1
SX200trxc 2004 Yamaha 200 SWSII
New:
Fuel lines and fuel
LP fuel pumps
Injectors
Plugs
All filters replaced including VST and VST/HP thimble at fuel regulator
Tested and cleared:

All check valves and vacuum lines to fuel system
All ignition in spec to CDI troubleshooting with DVA
Comp at 128–129-128-126-128-129 (cyl listed 1-6)
All tests run in tank not muffs

Motor starts but stalls before being able to test fuel pressure running. Turn ign to on but not started, hear HP pump cycle and hp fuel pressure tested off return line Schrader is at 10-15psi. Running PSI on same line is specd at 35.6psi. My assumption is that reading should be spec engine running or not being its an electric pump. Cant get it to run long enough to get a mighty vac on the regulator to test it per Yamaha factory manual. When leaving the key on and checking the HP line for leaks I find none and pressure holds at 10-15psi.

Interestingly if I bypass the regulator by pinching off the return fuel line from rail to VST motor will idle fine, problem is the Schrader to test HP fuel line is at the VST and It doesnt allow a reading.

Im down to the VST DC fuel pump btw getting 11.8v, or the regulator. That regulator is $300 and the pump is about the same, Id really like to eliminate one instead of replacing both.

I pulled the regulator and drew 25psi with a vacuum tester and it held without leak down.
 
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