1990 120 L Drive weak spark on #1 and #4

[brandonv]

Hello.

I think I've found my issue.... cylinders #1 & #4 (top and bottom cylinders) are getting a very weak spark. Since #2 & #3 are getting a nice blue arc I'm doubting its the magneto. I've got a 90' 120 L Drive with the Prestolite ignition and I noticed there's 2 CD modules.... does one control spark to cylinders 1 & 4 and the other to 2 & 3?

Also my plug on #4 looked pitted and very rough, unlike the rest. Would this have been from running the motor with weak spark on 2 cylinders? Plug #1 did not look pitted like this one did.


Thanks.

 

[contractorguy]

Re: 1990 120 L Drive weak spark on #1 and #4

First, swap the plugs around and see if the weakness follows the plug. If not, check the grounds on the 1 & 4 coils. The cdi's are 1-2, 3-4..... don't think that's the prob..