ICS MP5 spring compression issue...or not?

[BoneHed]

First let me tell you what I know as I bought this gun used from ebay from someone who bought it from an estate sale so it's history is unknown.
The battery connection that comes out of the gun is larger than what comes stock on a 9.6 v battery....it has the type used in RC cars. When I received the gun I charged one of my old rc batteries to give it a try. When I pulled the trigger all I got was a "click" the kind of click that says: Hey your battery isn't strong enough to compress the spring. So I had a new 9.6 on order so I waited till it came in, charged....completely with smart charger, installed it, and "click". So I tore down the gear box, checked shimming condition etc, everything is nearly new and tried again. This time the gun went through a partial cycle but stopped before the piston was completely compressed and then "click". I can go in to the gear box in my sleep now but finally installed what I "thought" was a weaker spring.....again, a partial cycle that stops and then just click. If this gun was upgraded with a much stronger spring would it make since that I need something bigger than a 9.6 or am I missing something. What type of connection comes on larger batteries. The gun is sweet with H&K full rails Peq battery box all metal etc and I want to get it going.....I'm at my wits end. Any guru's out there tuned in would be thanked profusely for any input. Oh, one other thing, I pulled the motor and inspected the brushes, they werent making good contact and the contact on the motor was in marginal condition at best so I ordered a High Torque motor to replace it.....same thing happens, partial cycle, then click. Thanks to all.

[Assault Pioneer]

Double posts about the exact same thing on this forum are NOT respected, if it does not belong in the sub forum you posted before a mod will move the post for you, please do not repost anymore

[Rock 'N' Roll Outlaw]

In his defense I informed him of the mistake he initially made. Not everyone knows all the ins-outs of a place like this off the bat. Relax.

Did you check the motor height? Does the gearset employ an anti-reversal latch? What about the wiring? Any of the insulation show signs of snagging or ripping? what about shorts? Do you smell anything when depressing the trigger, like something burning? Also make sure you're using the proper battery. Just because the voltage is right doesn't mean its the right battery. Maybe its not holding a charge?

[BoneHed]

I fixed it, mechanical things I understand, electrical hardly at all. I was using jumper wires between the gun and the battery since the plugs didn't match, well, I changed out the plug head and.....WOW, I assume wire gauge was too small.