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620owner

Engine shake at shut off

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I'm getting a slight engine shake at shut off. Just swapped the tranny, wondering if I weakened a motor mount ?

I don't think I have a broken motor mount, drives great but it just started this after the swap.

Could it be something else ?

 

 

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Usually my 620s would wobble when shut off cause of dieseling alittle after swapping in a Weber without the fuel cutoff solenoid anymore.

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Try put it in gear before shut off see what happens.

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Running original, Hitachi Carb. 

Not acting like dieseling, just a little stumble/rock when killing the engine.

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Not completely a diesel run-on, I know that shut-off shake/rattle/wobble all too well for that half second.

 

Bad gas, vac leak, gunk in shut off solenoid maybe ?

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So this is something it had not done before? It's definitely not the mounts though. They're designed to let engine wobble. Did you change the timing by any chance? beyond that, I'm with nl320what. 

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Did you remove the engine when doing the trans? May have upset something.

 

 

Check the idle cut is connected. It should make a clicking sound when the ignition is turned on/off/on/off.

Did you change spark plugs?

Did you replace thermostat?

Are you using a different gas than normal?

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No didn't remove engine. I'll check the idle cut.

nl320what said bad gas.... come to think i'm running out a tank from last fall and it's down under 1/4 now.

Didn't give that a thought. The truck sat over the winter with a full tank in the garage.

I just swapped the tranny and  started driving it again. I'll top it off with premium and see if that makes a difference.

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I'm getting a slight engine shake at shut off. Just swapped the tranny, wondering if I weakened a motor mount ?

I don't think I have a broken motor mount, drives great but it just started this after the swap.

Could it be something else ?

 

I'll take that as not removing engine.

 

Try the gas, you have to fill it up anyway.

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Try put it in gear before shut off see what happens.

AKA Clutch Kill

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Just be in the habit of using the clutch to kill the car.

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Causes of engine 'run on' or 'dieseling'

 

 

Idle too high for idle cut to have any effect.

BCDD set incorrectly causing a fast idle.

Idle cut stuck open, or insides removed or carb replaced with one that doesn't have one.

Carb flooding, making the idle cut useless.

 

If the idle is correct, carb not flooding and idle cut working there shouldn't be a problem. If you have an old carb without an idle cut, the following may cause run on...

 

Engine running too hot.

Spark plug range too hot

Excessive carbon build up

Compression too high / Too low an octane gas

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Just be in the habit of using the clutch to kill the car.

I got in the habit of doing this before I knew how to fix the dieseling so I can do it perfectly, now I have no idea if my trucks diesel or not because it's a habbit :)

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The most likely issue is bad gas, but also look for vacuum lines that don't fit tight or got damaged.  Replace all that are brittle, hard, cracked, or don't fit very tight.  Check that the vacuum unit on your distributor can hold a vacuum indefinitely.  Re-torque intake and carb hardware.  

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Also if the rpm at idle is a little high,it diesels.

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