Hi again Tom,

You are getting good information from the other posters on here and you are wise to absorb any wisdom on here!
More than a few of us have seen different scenarios of how the electromechanics can play out on a car.

I would like to correct one slight misstatement on battery voltage when cranking the engine.
The overall system voltage will drop to around nine volts under such a load.
If those who have dash mounted volt meters or a data holding DVM will see this. The dash meter just plummets to the left and “depending on the battery” you can see the dome light dim or even flicker out!

You can try using your meter to look for high resistance of you cables while cranking.
You place both leads on the same sides of the same cable!
Expect to see zero voltage reading!
It should stay that way during cranking or be a very very low reading during the crank.
If the numbers go up, to the right of the decimal point, as it’s an exponential reading of resistances. The bad connection will cause the voltmeter to start picking up that the reading is now going across from pole to pole of the battery or it “posts,” as we called them.
As we know a post to post reading tells us the full battery voltage reading.
So any number above zeros, is in actuality a resistance reading!
As the another poster has stated, this will cause the wire to warm up!
Depending on the amount o resistance, you would have to be very fast to “catch it,”
IMO, ALL THINGS ARE POSSIBLE with GREMLINS, (:-)

As far as the tightness of the engine the turning of the crankshaft, that Amarin suggests is a normal test of confidence to get a “feel” of the engine and it’s compression cycles if the plugs are left in.
With the plugs out, a torque wrench reading should be of a low foot poundage.
There may be specifications published someplace but I do not know them.
Due to the sizes of engines this does vary, naturally!
So the “Feel,” is a subjective matter of what you think the starter can turn!

The next thing that affects the starter more and that would be a problem with the flywheel teeth especially on some automatic transmissions. I have no data to “conjure” up on the 240’s having many issues with this though?
It may be possible that there is some damage with them, if you are truly having an engagement problem!
The only way you can see those is through the starter mounting hole. Any damage would be to the leading edge of the teeth on the starters side.
If they are mushed or chipped beyond their normal leading machined edging there could be something up!
Rotate the engine to get a view around the periphery for any spot that may be worse.

On Ford vehicles, they are known to change up starter tooth mesh number count. Mostly, I have heard it on their diesel truck lines. This during midstream production runs in the past.
A One tooth change in count can raise hell with rotation into the pitch depth or cause an immediate lock up!
Just pull aside and talk to an Auto Electric shop that rebuilds units and you will see their heads wobble in agreement!

Luckily Volvos have stayed really standard over the years, even though, the electric motor size changed!
This can cause a shift in this area.
Your motor should be the small motor type than that of earlier models that spun over slower in it sound it makes!
Maybe something is wrong around this.

How long have you owned this car?

Phil