After Reeds,stuffers, and hydrotec heads I've lost power.

**Degan** · 06-30-2020, 08:48 AM

Originally Posted by allstock

Ok, having read threw this whole thread. Here is my 2c. 148psi on an OX is way high. They have a big exhaust slot in the port to lower cranking compression, so you can add 10psi to cranking compression for an “accurate” cranking compression number. So 158psi. Will need 100 octane imo for that to work. If it is in any type of failsafe, or if the knock sensor is doing its job, it will pull timing and run exactly as you have described. If you bought those heads used, someone has cut them. You should have max 140 psi cranking with those heads. Maybe find a different compression gauge and try again. It sure sounds to me it’s running in failsafe. A Yamaha “winky-blinky “ can give you codes.

I will try a different gauge and report. The heads are new from hydrotec. Definitely cut down but I assumed a standard and usable amount. Idk.

Also. Can a bad crank shaft seal cause these kind of issues? I have been noticing a slight growling/squeeking when I have the cowl off running. After watching a bunch of you tube videos about what a bad crank bearing sounds like I think my upper one may be on the way out. That'll give me a reason to tear it down and replace all the bearings I may have damaged with water.

**allstock** · 06-30-2020, 08:58 AM

Originally Posted by Degan

I will try a different gauge and report. The heads are new from hydrotec. Definitely cut down but I assumed a standard and usable amount. Idk.

Also. Can a bad crank shaft seal cause these kind of issues? I have been noticing a slight growling/squeeking when I have the cowl off running. After watching a bunch of you tube videos about what a bad crank bearing sounds like I think my upper one may be on the way out. That'll give me a reason to tear it down and replace all the bearings I may have damaged with water.

I would call Hydrotec and get their input on the heads. Any Hydrotec head I have tested was 135-140 psi.