erractic rpm overspeed with io540

[preid]

my apologies as I know this was covered before however I'm having issues with pulling any info on this from the "search" engine.
My RPM is steady until about 2600rpm when it seems to quickly jump to 2800-2900rpm than goes back to 2600. I have not stared at it to determine how often or consistent it does it but need to determine what the best solution has worked for others before I start pulling the p-leads and resoldering.
thx

 

[eddies]

I have  cut this from a previous response  to a post on 'Tach erratic'

Do you have the recommended resistors in the RPM sense leads? If you do not have any resistors, you should refer to the install manual to find the value recommended. If you have them installed you may need to increase the value of the resistance.

Cheers
Eddie

 

[snowyriver]

I have an 0360 and am still having the same problem with the Skyview. I think the manual recommended 30k. It's getting better but I am up to 100K size at this point. When I switch to just one mag it calms right down. Otherwise it starts jumping around 1800 and I've seen it go from 2200-2900, 2500-3300, ect. I wonder if anyone else with the same eng and mags has experienced this?

 

[preid]

Yes, I am. I called support and they told me to keep going higher than 100k, maybe up to 150k. Problem, other than the constant soldering in the area, is that one loses the lower rpm if it is too high.

 

[jc2da]

My RPM readings have been very steady and reliable also on an IO540 with p lead pickoffs from 2 slick mags. I get reliable high and low RPM readings up to 2730.

Unfortunately, i dont have what value resistors i used in my notes, but it was at least 100k and was just whatever i had in my parts bin.