12R Valve Adjustment and a few other bits.

Hi All, 

The Hiace is coming together! Carb refurbished, electronic ignition in the post, cooling system fully refurbed and a few other bits. 

Next up is to refurb the vacuum advance mechanism which is not functioning properly, refurb and line the fuel tank, recore rad (piece of mind..) and fit out the camper bits in the back. 

My questions, if anyone can assist are as follows. 

1. Idle mixture adjustment screw not working and van not idling on pilot jet. I've stripped the carb and have confirmation pilot jet, air horn etc are all clean and open. When I back off idle adjustment screw (on accel linkage) the revs drop and she cuts out. When I wind it in to get a decent idle, the van hunts up and down on the RPM's and wont settle. 
   Any recommendations? I have a intake manifold gasket in the post and will delete the crankcase breather to rule out any vacuum leaks on manifold that would be diluting the pilot jet supply. Bad fuel? Tank not the cleanest. 
2. Valve adjustment. The book for 12R states one must adjust valves while running.... I'm assuming this is a translation issue from japanese to english? Do i just run her up hot and then make the adjustments? Bit mad! 
3. Water temp gauge not working. New sender fitted and still no movement. Any idea where to access this? 
4. VSV solenoid between the Carb vacuum hose and Vacuum advance mechanism. When i got the van, this was disconnected. Any idea what the hell it is? Why would one switch vacuum advance? Part number leads me nowhere.   
   
   Any assistance is greatly appreciated!

Much love, BRENT_EAGLE

VSV is a vacuum switching valve, it seals or vents the diaphragm on the dizzy under constant vacuum it will hold the advance

as for the carb it sounds like its clogged or just worn, if you are having dizzy issues it will idle like carp (timing too far advanced)

you can do the valves cold 20 thou IN, 25 thou Ex

Thanks Bob. 

In regard to the VSV. Would this being removed cause any issue to the engine running? it looked well dead when i removed it from the van (rusted to bits with wires cut). Me and a mate decided it was some sort of roll over device haha. Too many engineers will always convolute the issue. 

Distributor will soon be getting a refurbed vac advancer and upgrade to solid state points. She should be easier timed and a more consistent spark. I'll progress this and a supply of clean fuel and see if we can get her to idle on the pilot. 

Valve adjustment to the thou... My Coventry Grandad lived and died by the Thou; I like a mm meself. He'd be disgusted at my unwillingness to use imperial haha. I'll have to dig out the imperial feeler gauges (sounds regal). 

I shall likely do an update on the tank cleaning as It may come in handy to others. 

Thanks, 

I use both metric and imperial, it's Whitworth that throws me, it's been a while since I played with a carb (Old Zenith carb)

shaft play can cause vacuum leaks, yeah, been down that road a few times

rebuild that dizzy first, if there is a vacuum non-return valve on the crankcase make sure it's working as it should

BSW... Any thread will match with enough force and heat... 

This is my first foray into carbs. Fantastic things in themselves but I now appreciate the common rail fuel injection system so much more!!

Shaft play being the shafts of the butterfly valves? I may pack out the externals with a bit of marine grease (i'm not taking her apart again 🙈).

Will check Crankcase. 

Thanks Bob, much appreciated as always.