Hey Folks,
I'm looking for suggestions on how I might go about diagnosing whether or not the modification I did to the Secondary Slow Cut Valve (see image below) is working correctly.
This is on a OEM Aisin Carb (PN 21100-61141) from a 2F 12/1981 FJ60 USA.
After having successfully rebuilt the carb several months ago, the secondary slow cut valve began leaking gasoline through the valve to outside the assembly.
Following MUD modification guidelines, I removed the valve assembly, pulled the valve from the housing, tapped the housing and threaded in and JB welded a bolt.
The modification allows for gas to be drawn into the second barrel by vac alone (vac created by the position of the butterfly - #13 in diagram below - on the secondary throttle shaft), no longer requiring the the mechanical opening of the secondary valve - #11 in diagram below - to allow gasoline to enter that circuit. (see diagram below)
I am wondering if after having done the modification, whether excess gasoline is entering the second barrel and causing performance issues...and if so, is there a way I can test to rule out whether or not is or isn't working correctly...because if it isn't, then I would have to get another, properly working Valve assembly and they are rather pricey (PN 21346-61140)...
The symptoms I have noticed since the modification are poor gas mileage (went from 12 city 15 highway before the mod to half that after the mod) and sluggishness under acceleration.
Any suggestions on how to rule out poor metering or fuel 'leaking' through the carb (especially this secondary circuit) would be helpful.
Thx.
I have noticed that the fuel level in the fuel bowl goes down overnight, but I attribute that to evaporation? The fuel pump is new (fuel filter fills about 1/4 full at idle)...no gas leaking from pump into crankcase...
All the Emissions systems/components are working correctly (new EGR Valve and Modulator), new vac lines, no vac leaks (excellent vac at idle 21 inHg), ICS working correctly.
Ignition Vac advance is working correctly (although I haven't ruled out weak springs as a cause for these symptoms, either, just can't find new OEM or comparable springs and don't want to risk messing around with finding suitable replacements until I rule out carb related stuff).
Base timing is set at 7* BTDC.
I'm looking for suggestions on how I might go about diagnosing whether or not the modification I did to the Secondary Slow Cut Valve (see image below) is working correctly.
This is on a OEM Aisin Carb (PN 21100-61141) from a 2F 12/1981 FJ60 USA.
After having successfully rebuilt the carb several months ago, the secondary slow cut valve began leaking gasoline through the valve to outside the assembly.
Following MUD modification guidelines, I removed the valve assembly, pulled the valve from the housing, tapped the housing and threaded in and JB welded a bolt.
The modification allows for gas to be drawn into the second barrel by vac alone (vac created by the position of the butterfly - #13 in diagram below - on the secondary throttle shaft), no longer requiring the the mechanical opening of the secondary valve - #11 in diagram below - to allow gasoline to enter that circuit. (see diagram below)
I am wondering if after having done the modification, whether excess gasoline is entering the second barrel and causing performance issues...and if so, is there a way I can test to rule out whether or not is or isn't working correctly...because if it isn't, then I would have to get another, properly working Valve assembly and they are rather pricey (PN 21346-61140)...
The symptoms I have noticed since the modification are poor gas mileage (went from 12 city 15 highway before the mod to half that after the mod) and sluggishness under acceleration.
Any suggestions on how to rule out poor metering or fuel 'leaking' through the carb (especially this secondary circuit) would be helpful.
Thx.
I have noticed that the fuel level in the fuel bowl goes down overnight, but I attribute that to evaporation? The fuel pump is new (fuel filter fills about 1/4 full at idle)...no gas leaking from pump into crankcase...
All the Emissions systems/components are working correctly (new EGR Valve and Modulator), new vac lines, no vac leaks (excellent vac at idle 21 inHg), ICS working correctly.
Ignition Vac advance is working correctly (although I haven't ruled out weak springs as a cause for these symptoms, either, just can't find new OEM or comparable springs and don't want to risk messing around with finding suitable replacements until I rule out carb related stuff).
Base timing is set at 7* BTDC.
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