Mercury 1150 ignition problem? Newbee questions

[float time]

Please bare with me I am a newbie to the site. I recently purchased a party barge pontoon with a 6 cyl Mercury 1150 (model # 4702491). After research I am thinking its a 1977 Model year.
Have been out boating several times with the only problems being a little hard starting when cold of course (sounds like they all had this issue) and slight idle problem when going from forward to reverse, (it sometimes would stall).
However this last outing ended with a stall at idle and not able to restart. it ran great wide open up and down the lake with what seemed to be no running or low power issues.?

I have done the following
confirmed the coil will fire with good hot blue spark when I test by connecting the brown and white wire together and momentarily grounding the black wire at the coil.
I have tried to then check for spark at the plug wires and the spark is weak! like I almost have to have the metal part of the screw driver a 1/8" from ground before I will get any spark at all. I first tried with a simple spark tester and it wouldn't even show a spark with that.
Does this mean its the trigger in the distributor? Is there a way to test the trigger? They are expensive from what I see so I just want to make sure its bad...

Also I figured someone would ask if I did a compression check so below are my readings

cyl 1 =100psi
cyl 2 =130psi
cyl 3 =120psi
cyl 4 = 140psi
cyl 5 = 135psi
cyl 6 = 130psi

it seams cyl #1 is a little low but it never seemed low on power with running (could this be a stuck ring?) I forgot to mention this motor was in storage sitting for 2 + years before I purchased..

Any direction / comments/ words of wisdom would be good help..
thanks

 

[Chris1956]

Your compression is fine, IMO. Remove the distributor cap and clean it with a cloth and some solvent to remove any grease. The rotor is non-removeable and very fragile and expensive. Make sure the distributor wires are clean and tight on the switchbox. Check the mercury switch (blue condenser-shaped thing) above the switchbox. It is designed to short out the spark, if the motor is tilted up.

Important - check the spark plug wires for cracks in the insulation. Also check them end-to-end for resistance. There should be zero ohms resistance as they are stranded stainless steel conductors. The plug wires unscrew from the distributor cap. You can replace the spring spark plug connectors, if they are corroded.