How To Test Cdi Box 780 Triple - Snowmobile Forum: Your #1 Snowmobile Forum

ceasar01 · 12-18-2003, 09:43 PM

IS there a way to test my CDI box the motor seems to lose a third of its power after running for a while

finn · 12-20-2003, 12:52 PM

The CDI can not be tested , but the stator and coils can . if they pass their tests and you still have an ignition problem , then its the CDI....but the stator is the most common problem.....Jari

96ultra · 10-26-2009, 07:44 PM

I have a similar problem where my 96 ultra will run great for a few minutes until you let off the throttle and it just quits. After checks, determined that there is no spark but after a few minutes I get faint spark and an little longer and its back to normal and will start great. Any ideas????

**smallengineguy** · 10-26-2009, 09:15 PM

COil or stator in that order.

Blaine1 · 10-27-2009, 01:29 PM

Quote:

Originally Posted by smallengineguy

COil or stator in that order.

What he said. Here is a video I put together showing how to check and replace a stator. Even though it is a cat, the same principles apply for both testing and replacing:

Stator testing out of a sled
YouTube - Stator Testing a 2 Stroke Stator

Stator testing in a sled:
YouTube - Stator Testing in a sled

Stator removal:
YouTube - Installing a Stator Pt.1 Removing it

Stator reinstall:
YouTube - Installing a Stator Pt.2 Putting Everything Back Together

96ultra · 10-28-2009, 06:34 AM

I originally thought about the coils, however I have a hard time believing that all three of them would show the same symptoms at the same time. Agree or disagree?

Blaine1 · 10-28-2009, 06:56 AM

Quote:

Originally Posted by 96ultra

I originally thought about the coils, however I have a hard time believing that all three of them would show the same symptoms at the same time. Agree or disagree?

If you have 1 bad coil and they have a jumper wire between them (like Cats do) it can effect all 3.

**smallengineguy** · 10-28-2009, 01:39 PM

Doos don't have that jumper, besides the common ground.