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Been a busy couple of weeks on the Pinz. Wheel drive leak fixed, civilian plugs and cap installed, Pertronix electronic ignition, oil cooler leak fixed, adjust valves, etc.... Everything was fine until the carb rebuild. Everything went well until I reinstalled them. I can not get the butterfly's closed unless I push down pretty hard on the throttle lever on the carb. Pinz starts great, but is idleing too high even with the stop back screw fully backed off each carb. It is mainly the rear one. Before I started messing with the throttle spindle, just seeing if anyone has any advice on 1. How they got out of adjustment. 2. how to adjust them fully closed when the lever is resting all the way down.

Thanks

Check in this order, hand throttle realesed and loose, manual rods not binding, throttle lever not contacting engine tin, Bent / twisted throttle shaft(common on brass shafts) and last, rear carb rod on lower belcrank ball, front on top ball.

I played with the linkage for an hour. It still would not idle down or shut the butterflies. Disconnected everything from the carb. With everything disconnected, I had to push pretty hard on the throttle lever to get them to close and to get it to idle down.

Twisted shaft , incorrectly installed butterflies, or pump rod too long, should be around 80mm.
Disconnect the pump rod on the offending carb and then see if it will close with ease

I did not adjust any of them. I checked the play in the pump arm, was loose when closed. I will re-check them tommorrow. Thanks Jim.

I had the same symptoms twice.

First time it was the bell-shaped washer behind the hand throttle gripping the cable, second time it was a bent throttle shaft...

Both are in your post Jim, congratulations on your quickly put-together checklist

Jan

Getting closer. When I set the timing after doing the ignition, I set it at around 1500 rpms as I had no way to measure the RPM's of the engine. Timing as too advanced causing the idle rpm's to go up. Better now, but i have a linkage problem. Still idles at 1200 rpm. Both carbs arew synched. If I lift up on the gas pedal, is goes to 920. Hmmmm.......

Disconnect the main rod from the pedal at the bell crank, also check for a loose or broken motor mount, this will cause the rod to be too short.

Man, this thing is driving me crazy..... Jim, thanks for all the help. Here is where I am. With the linkages off, the carbs idle fine. Idle mixture screws out 1 1/2 turns, rpm 930, cfm on carbs around 14. As soon as I attach the linkages, rpm's shoot up to 1200 and one carb (rear) goes to 19 cfm, other drops some. No matter how I adjust the linkages, it keeps getting out of synch.

The arm on the valve cover when linkages are off is at around 7 'clock when linkages are not attached. When attached, it is around 10 o'clock. Spring is attached, so it is getting pressure to pull the throttle levers on the carbs down, but yet the RPM"s increase when I attach them.

Although the Pinz was running fine before I started this, it was a mess. Both were leaking severely, throttle linkage was bent, spring on the pivot arm on the #3 valve cover to the attachment on the number 4 valve cover was missing, etc.... Although it was a mess, it idled and ran great. I am basically rebuilding everything back to factory, but have no real base to start with since it was so messed up to begin with. That being said, I have no idea if the carbs were in synch, where idle screws were set, etc.....before I did the rebuilds.

Well, thats about it, any help is mucho appreciated.

I hope you already realize this, but have you lengthened or shortened the linkages by slightly unthreading the rod ends? You need to do this to get the linkages to both carb balanced, and to some extent get the linkages the correct length to NOT hold the throttles open...

Just be sure to not have them so unscrewed that the rods can rotate and unscew one side while tightening the other side and come loose while driving ("Wow, where did all my power go" when one carb went to idle on the freeway - ask me how I know).

Just a thought.

Jim M.

Also check that your choke is closing all the way at the carbs. From the passanger side, at the closed position the small levers should be leaning forward, towards the front of the cab. Be sure they are bottomed out on the pin stop.

I find if I leave the choke cable pulled out by 1/8 inch while tightening the screws onto the cable wire, they will function to full close during use.

Miles

When I took off the carbs for the rebuild, they had a thick 1/4 in gasket between the carb and the manifold. Used the thin one in the kit for replacement. Any chance the carb sitting lower could have effected something? Perhaps float level?

When I took off the carbs for the rebuild, they had a thick 1/4 in gasket between the carb and the manifold. Used the thin one in the kit for replacement.

Ahh, that's the answer. Now you carbs are 1/4" closer; the thick gaskets are intended to help insulate the carbs from heat traveling up the intake manifolds.

Put the 1/4" spacers back in and seal between them and the carbs with the new gaskets.

Jim M.
712W and 710M

Removing the insulators also made the linkage too long.

Would not having them on there make in difference on the idle? IE- higher than normal?