Powerhead for a 200 HPDI

I turned 1000 hours on a pair of HPDI 200's. Talked out loud at how great the motors have been and two hours later discovered I lost complete compression on my lower left cylinder in the starboard motor. Yes, complete compression as in you can put your thumb over the sparkplug hole and turn over the motor.
Two questions to the folks here who know:
1) When I bought the boat one of the cylinders (don't remember now which one) was off more then 5-10 psi. I suspect this one. What would have caused complete lost compression?? The motor still runs fine, just obviously less one cylinder?
2) Where is the best place to have my powerhead rebuilt or where is the best place to buy a rebuilt powerehead? I will be doing the swap myself.

Thanks,
Turmoil

[robert graham]

Maybe piston rings are stuck in grooves with carbon. Check compression in other cylinders, might be low also. Maybe you could just go through the powerhead, decarbon, new rings, maybe new pistons. Good Luck!

Found the problem!

As you can see I found the problem. So with that said....can someone point me in the right direction for a quality rebuild?
Thanks,
Turmoil

[msilva2467]

Don't know where you are located but I used a shop out of Homestead FL and was very happy.

As you can see I found the problem. So with that said....can someone point me in the right direction for a quality rebuild?
Thanks,
Turmoil

Yes contact MAR-FAB (Marine Fabrication Inc) in Sparta TN, they supply top quality cores. They are a wholesale only supplier but they will be able to tell you who they supply in your area and you can get what you need through them or arrange a rebuild.
1-800-476-1554