Frank Acampora
Supreme Mariner
- Joined
- Jan 19, 2007
- Messages
- 12,004
I just found out the hard way: If your 125 is stuck in full up tilt, and if you attempt to force it down by pushing on the prop or cav. plate, and if there should be some problem with the internal relief valving, then you will blow the head off the trim cylinder. It lets go with an impressive bang. Does not break the five bolts, breaks the head casting itself.
I had an old head with some corrosion, so I would not normally use it. I retested and sure enough--blew off the head in the same failure mode: blows out a rough circle about the size of the trim cylinder. Interesting! I must have been generating well over 3,000 PSI as the system is supposed to hold 2,000 and probably has a 50-100% margin of safety. Amazing that the O ring seals held that pressure.
I have not yet disassembled the system to see what valving allowed me to generate such damaging pressure. When I get a round tuit, I will repost results I found.
I had an old head with some corrosion, so I would not normally use it. I retested and sure enough--blew off the head in the same failure mode: blows out a rough circle about the size of the trim cylinder. Interesting! I must have been generating well over 3,000 PSI as the system is supposed to hold 2,000 and probably has a 50-100% margin of safety. Amazing that the O ring seals held that pressure.
I have not yet disassembled the system to see what valving allowed me to generate such damaging pressure. When I get a round tuit, I will repost results I found.