Leak down test 7.5

[russ]

Putting gear case back together and tomorrow want to do a leak down test. How much pressure do I need and how long do I let it sit ? Thanks all Russ…

[labrador-guy]

Russ I hope for five pounds for five minutes! If your 7.5 is an OMC motor they are a lot more tolerant to water than a Mercury. They are all brass bushings. The old Mercs call for corn head grease. They have all roller bearings and they rust quickly. Merc’s are a lot harder to seal up than an OMC. IMHO Either one needs to be checked for water occasionally and drained before freezing temps arrive.

dale

get’em wet….don’t let’em get!

[russ]

It is a omc. Thanks Dale….

[fleetwin]

Well, these “clam shell” gearcases are pretty tough to seal properly. Get a big bucket that you can submerge the gearcase totally under water… Set the pressure at abot 5-7PSI and submerge it in the water…Look for bubbles rotating the shafts and shifting the gears…
CAUTION:
You will need to have the impeller housing in place (no impeller) and screwed down securely before pressure testing. The pressure will just push the upper bushing/seal hsg off its gasket if not secured properly…

[labrador-guy]

As always fleetwin is right on! Remember the screw heads. They are inside the spaghetti seal and they will also leak around there heads.

dale

[Author]

Posts