New powerhead installed, a couple of questions

[grouper sandwich]

I installed a new powerhead (from boats.net) on my Yamaha 70TLRS. The oil pump malfunctioned and destroyed the middle cylinder on the old one. I'm nearing the end of my 10 hour break-in on the new one and had a couple of questions.

1) I'm at 7.5 hours and have enough pre-mix gas left in the tank for about another 1.5, possibly 2 hours. Is it OK to introduce un-mixed gas at that point or is that last 1/2-1 hour critical? I have verified that the oiling system is delivering oil. I can certainly make up more pre-mix, but if I can stop after 24 gallons that would be great.

2) What needs to be done now? Check torque on head bolts? Change plugs? Anything else?

I checked the compression on Sunday evening after reaching 7.5 hours and I'm at, top to bottom, 145, 140, 140. I have followed the break-in procedure to the letter to this point as proscribed in my manual.

[rodbolt17]

wanna make any bets it was NOT the oil pump that took out a cyl???????
its what we call piston failure analysis.
typically oil failures take out cranks and rods.
lean running and over heats take out pistons.\
but to your question.
yep its ok to go back to gasoline only and yes recheck headbolt and ex cover bolt torques.
oil pumps get blamed by to many shade tree backyardigans.
even by supposed trained techs.
its an easy explanation to a customer when you have no clue.

[grouper sandwich]

wanna make any bets it was NOT the oil pump that took out a cyl???????
its what we call piston failure analysis.
typically oil failures take out cranks and rods.
lean running and over heats take out pistons.\
but to your question.
yep its ok to go back to gasoline only and yes recheck headbolt and ex cover bolt torques.
oil pumps get blamed by to many shade tree backyardigans.
even by supposed trained techs.
its an easy explanation to a customer when you have no clue.

Thanks for the response. I opened up the old powerhead this evening and there was no scoring in the cuylinder, but there were sharp pieces of metal all over the top of the piston. I got one in my finger as a memento. I'll do a complete autopsy soon. At any rate, it's broke. I replaced the oil pump and hoses when I replaced the powerhead. And yes, I'm a bonified shade tree backyardigan. I even hung the engine from a maple tree limb.

[amahaork]

why Yamaha shop manual never mentioned to re-torque head bolts after break-in period?

[rodbolt17]

look under maintanence. its part of the 20 hr check.
oil pump failures are rather rare and typically are not cylinder specific.
they get blamed a lot but its rare.
I see more water in the oil tank failures on inline motors.
that oil pump will pump water just as well as oil.