Force 85 really difficult to start

[Nordin]

I have not read through the whole thread and checked what you have done but go through Frank A steps, check choke butterflies, float levels, clean the carbs and check for spark at all 3 cylinders.
The sparks should jump at least 3/8 in but 7/16 in is preferable.
About you compression gauge I can say that it is a premium gauge no cheap Chines crap.
I think it is from the 60.es or early 70.es.
I used this kind of model in the late 70.es when my farther and I restored cars.
I was about 17-18 years old and new to working with all kind of engines.

 

[jerryjerry05]

You said: "How to check the cdi and ignition coil?"
The only way to check the coil is to swap it with another coil.

Checking the CD or pack:
IF NO FIRE ON ANY CYLINDER: 1. Disconnect the kill wire AT THE PACK. Check for broken or bare wires on the unit, stator and trigger. 2. Using the Fluke meter with the 511-9773 peak reading adapter, or CD-77 and 511-9770 piercing probes, measure DVA voltage of the stator between the output wire sets. With everything connected, readings should be approximately 180 volts or more. Resistance readings between the stator wire sets is from 680-800 ohms (CDI will read 300-400 ohms). 3. Disconnect the rectifier and retest. If the engine fires, replace the rectifier.
OR IF YOU HAVE SPARK ON ANY CYLINDERS THEN SWAP IT WITH THE OTHER PACK.