Vacuum testing OMC 800 upper

[allen.st]

I have just finished putting in a new water pump and all of the seals, gaskets and O-rings in the upper because it was getting water in it.<br /><br />My problem is if I pull a vacuum from the dip stick hole it will hold 15 hg but if I check it from the drain hole it will not hold, just a steady drop from 5hg. Any ideas where it might be leaking?<br /><br />Thanks.

 

[allen.st]

Re: Vacuum testing OMC 800 upper

Ok, I found if i put plumbers putty around the vacuum pump fitting (rubber cone) that it held 15 hg for over 5 minutes and after about an hour it was down to 5hg. Is this ok?<br /><br />also I have seen oh here how to build a pressure test set up with a 3/8's threaded hole but now I cant find it anymore, and my memory is short

 

[jawzzy]

Re: Vacuum testing OMC 800 upper

Not sure if it's accurate, but I was told that the pressure should hold for a 24 hour period to be sure.

 

[allen.st]

Re: Vacuum testing OMC 800 upper

Thanks jawzzy, I have read everything from 2 hours, over night, to 24 hours on pressure test but not much on vacuum testing except instead of 15hg it might only hold at 5hg for 10 minutes????<br /><br />I was hopeing don s might have a picture of one in his archives. He has come up with some hard to find stuff in the past There is quite a bit of discussion on here about pressure testing but not about how or where they got it.

 

[jawzzy]

Re: Vacuum testing OMC 800 upper

sorry, didn't realize there was a difference between a vacum and a pressure test, as I was referring to a pressure test. My bad

 

[allen.st]

Re: Vacuum testing OMC 800 upper

that is ok, pressure test is to make sure that it does not leak gear lube out and the vacuum is to make sure it does not suck water in. Hmmm OMC suck???

 

[KaGee]

Re: Vacuum testing OMC 800 upper

Yep, they all do!