BoatCop wrote:When was the last time service was done on the lower unit? It's possible that the plug may not have been tightened properly and slowly backed off.
You'd be surprised at how long a lower unit will run with just water for lubrication. We had one (on a 250 Verado) that, when serviced, drained out 100% water. There was no trace of oil in it. No idea how long it had run like that, but it was no more than 100 hours, since that was our service interval. Pressure test showed a leaking main rear seal, and inspection of the gears showed no significant abnormal wear.
Re sealed and fresh oil, and no further issues.
Yours had to have been running like that for some time in order to grenade.
I had changed the lower unit oil, two years ago, at the end of the season. But I didn't use it last year as I was rebuilding the pontoon. Previously, I change the oil every year.
I was thinking that, possibly, I didn't tighten the plug when I changed it two years ago, and that is the cause of this whole thing. But, I used it for 7 days this year. Everyone else that I talk to says, the motor will run about 5 minutes without oil before it blows like it did. I am not saying your wrong, but that is what I have been hearing.
It would be interesting to know how long the lower unit was running without oil, but I have no way of knowing. I know, from now on, I will glance at the lower unit, and make sure the plug is there, every time I dingy out to the toon!