Rpm needle jumping

[Gwywnc]

Hi I have a question maybe you guys can help me out. I have a 1984 Subaru gl with 4 speed. When I start the car the rpm needle will jump up to like 2 or 3 and makes a weird sound then comes back to 1. This happening with it out of gear and sitting still. Now when I take off I’ve noticed it will still do it on acceleration and the car will loose power for that second that it’s happening. But once I drive the car for say 20 minutes it stops doing it. I had to jump the car off today and can hear a distinctive whining noise coming from the engine when this happens. Anyone have any clue what this might be? Thanks   

[Steptoe]

got another tacho you can hook up to the coil to see if it does the same?

I know of a high energy coil set up on a totally different engine had a jumpy tacho - new seat of HT leads fixed it.

Diodes in alternators are reported to be source of some whining noises, try belt off alternator for a moment when you know you can make noise

[Gwywnc]

I tightened the alternator belt and it still does it. It’s like the clutch is slipping but it also does it out of gear and at idle 

[naru2]

Probably worn distributor bushings.Pretty common.

See if you can wiggle the shaft.Any more than barely perceptible movement is too much.

Another tach won`t read right either as the ignition primary signal is messed up.

[turfman454]

dealt with this recently. ON mine the wires to the coil were loose

 

[GeneralDisorder]

Have to rebush the distributor shaft. Or replace the distributor. Look up Philbin Manufacturing in Portland, OR. They can rebuild it. 

GD