how do I use Dwell meter?

[broken08]

Hello all,
1978 merc 165, all original as far as i know.
did the point, condenser, cap change and i did the best I could with the feeler gauge.
I have an old (obviously) dwell meter that I have never used. I hooked it up to negative coil and ground as instructed in manual. I crank the engine an the needle on the meter bounces off both sides of the meter so I can't really get a reading. However right after I stop cranking it sits at 35. Is that just coincidence or is that how it should be read? I would expect to see it hold steady while cranking, but then I really don't have any idea with this old stuff.
Thanks!

 

[Haut Medoc]

Re: how do I use Dwell meter?

Hello all,
1978 merc 165, all original as far as i know.
did the point, condenser, cap change and i did the best I could with the feeler gauge.
I have an old (obviously) dwell meter that I have never used. I hooked it up to negative coil and ground as instructed in manual. I crank the engine an the needle on the meter bounces off both sides of the meter so I can't really get a reading. However right after I stop cranking it sits at 35. Is that just coincidence or is that how it should be read? I would expect to see it hold steady while cranking, but then I really don't have any idea with this old stuff.
Thanks!

It's bouncing because the points are opening & closing....
Run the engine & read it.....

 

[bruceb58]

Re: how do I use Dwell meter?

On my meter, I can read the dwell while cranking. Yours obviously doesn't work that way.

 

[bigskiohio]

Re: how do I use Dwell meter?

make sure you have it on dwell not the other settings like tach and pnts. should not bounce , might have to zero yours out.

 

[Brewman61]

Re: how do I use Dwell meter?

Been a long time, but last I recall, my meter (still have it gathering dust somewhere) read the dwell angle while with the engine running. On the old GM distributor caps (for some of their V8's, anyway) you could open a little slide door on the bottom edge of the cap and do a fine adjustment of the points gap with an allen wrench. That was really slick. Easier than adjusting with a feeler gauge.
Any chance that some of the GM marine distributors work that way too?

 

[bruceb58]

Re: how do I use Dwell meter?

Any chance that some of the GM marine distributors work that way too?

No...kinda defeats the whole spark shielding requirement.

 

[broken08]

Re: how do I use Dwell meter?

so i tried it with the engine running and it held pretty steady at 30, so it sounds like i set my gap right.
strange the instrustions say to do it while cranking when that gives too unsteady a reading.
thanks all.