Low rpm, low top speed

[daddiotom]

I ate a rock on my 2003 Sportster 4Tec. Replaced housing and wear ring and had impellor cleaned up as it was not too bad. But boat would only do about 40 mph (GPS) and 6900 rpm so replaced impellor with a rebuilt one. Still no improvement in top end and RPM still only goes to 6900 whereas book calls for 7350 +or - 100. Pulled the sparkplugs; they looked white and clean and gap was at .030 but changed them anyway. Tried injector cleaner; no improvement. I always fuel with stabilizer. Also, there is a slight intermittent miss at idle.

Before I take it to service department (always a rip off) does anyone have any other suggestions? I suspect there may be an issue with one of the coils but I don't know how to troubleshoot them short of replacing all 3.

I hope this post isn't redundant but I couldn't find any other posts on the subject.

Thanks in advance!

 

[Coastiejoe]

A defective rectifier can limit both RPMs and thus limit top end speed. But it normally keeps the RPMs maxed around 4400 or so.

You can test it by disconnecting it and then going for a run.

 

[daddiotom]

Thanks for the reply Coastiejoe. Unfortunately, I can't find a reference in the shop manual for the rectifier's location. Any suggestions on its location?