'90 225 has a mind of its own.

[iammarcuse]

I have a 1990 225ETLD. I just got the motor and I am trying to figure a few things out. While cruising anyhere between 3500-4500 it will just all of the sudden speed up a few hundred rpm's like you hit the throttle. It will usually settle back down and may do it again. At higher speeds it seems to do the opposite. It will drop real quickly just for a second. Feels like hitting the rev limiter only I am between 4500-5500 and the limiter is 6250.
The carbs were brand new just before I got it and it does not seem like a fuel issue because the rpm changes are too quick. I know this motor has a bunch of sensors that affect timing.
I suspected a flat spot in the TPS but it ohms smoothly through the full range. Anyone wih experience with these computer timed motors have any ideas?

 

[birdbrain]

Re: '90 225 has a mind of its own.

I would do a spark gap test, you can make a spark gap tester pretty easy, just search the forum. This should at least point you in the right direction... ignition or fuel.