how to pressure test lower drive

[phil rogers]

I have a 77 mercruiser and I want to pressure test lower unit.I know you take lower plug out and Apply 15 lbs pressure but I dont know how long it need to hold pressure.I also want to vacuum test it.How long does it need to hold vacuum and how much vacuum.I also want to know lower unit seriel location and what unit it is the upper seriel is 444065 thanks phil

 

[Bondo]

Re: how to pressure test lower drive

and I want to pressure test lower unit.

Ayuh,.... Do a Search,... It's been beat to death,+ is All already here for the reading....

I also want to know lower unit seriel location and what unit it is the upper seriel is 444065

There's No serial # on the lower units,...
You have a Mod.1, Pre-Alpha...

 

[ziggy]

Re: how to pressure test lower drive

i think it's supposed to hold forever. vac. or pressure
i pressure tested mine at 12psi for 24 hours. rotated the drive shaft a few times inside the 24 hrs.
i vac. tested for about 24 hrs @ 5 hg. rotated the drive shaft a few times on that too.
i don't know where or if there's a number on the lower. and your upper s/n is pretty close to mine so i'd guess you have a mercruiser 1 drive also.. would need to know what engine to decide if it's a mc120/140, or a mc165 or a mc888 or a mc898, etc. i believe all these drives are the same except for the gear ratio..

 

[phil rogers]

Re: how to pressure test lower drive

thanks ziggy I have been looking everywhere for the specs on vacuum test your input is appreciated. thanks phil rogers