Different mag drop after annual

[Chuck]

I recently got my 2006 CTSW back from annual and now notice that on one ignition I get an rpm drop of about 100 and the other is about 50. Before the annual they were both about 50. I don’t notice any other issues, but am curious about this change. Any thoughts on what could cause this?  I do know the mechanic removed and cleaned the spark plugs. 
 

-Chuck

[Roger Lee]

It would be the first thing I checked. Plug gaps and trim plug wires 3/8" off the plug wire tip where it screws into the plug cap. 

Either could be a cause. Others things to. but these two things don't  cost anything and then you will rule them in or out.

[Anticept]

Check plug resistances, check plug boot resistances while trimming the wire as roger suggested.

Resistances should be around 5k for each item, and I would probably not allow more than 20% deviation.

Higher resistances can lead to timing shifts, weak sparks, and eventually dead cylinders.

[procharger]

He could have a slight difference in carb. setting or sync.??

[Anticept]

That's also true.

[procharger]

wish mine was only 100 or 50

[Mike Koerner]

I'm with Procharger. A drop of 50, or even 100 rpm, is insignificant. Mine varies more than that from day to day. According to my manual the maximum allowable drop is 300 rpm with a 120 rpm maximum difference between the two circuits.

Mike Koerner