LOWER UNIT WHY THE BOTTOM HOLE

[lonewolf5347]

FORCE 1994 120HP. HAVING A PROBLEM WITH THE LOWER UNIT. TAKING ON WATER MIXING THE OIL TO COFEE COLOR; CHANGEING THE OIL AND ADDING TRYING TO FINISH THE SEASON OUT,THE ? I HAVE IS WHEN YOU FILL THE LOWER UNIT YOU USE THE BOTTOM HOLE;AND WAITE TO IT EXIT OUT OF THE TOP HOLE,WHY CAN'T YOU USE THE TOP HOLE TO FILL?OIL WILL ALWAYS TRAVEL DOWN THIS MAY BE A STUPID QUESTION BUT I WILL LIKE TO HERE SOME REPLYS

 

[GoneFishin']

Re: LOWER UNIT WHY THE BOTTOM HOLE

The answer is pretty simple if you thonk about it...<br />The lower unit gear case is air & water tight (atleast it should be). If you fill it from the top down, air will get trapped inside making it difficult to get it completely full. <br /><br />Filling from the bottom prevents the air bubbles from getting trapped. <br /><br />A simple word of advice on your water leak -- Change the lower unit plug seals first. They're cheap & often overlooked. Don't make the same mistake I did & start with the internal seals!! That's a pain! Good luck!

 

[lonewolf5347]

Re: LOWER UNIT WHY THE BOTTOM HOLE

ARE TALKING ABOUT THE SEAL THAT ARE ON THE STAINLESS SCREWS?

 

[BayouBill-LDF]

Re: LOWER UNIT WHY THE BOTTOM HOLE

Lonewolf - change the seals' they are easy to change. Not the gasket's on the screws but the seals' on the prop-shaft. Repeated running with water/oil mix will cause BIG TIME damage and might 'total' your engine, at minimum it will be big $$ to repair.. fix seals' soon. Good Luck<br /><br />Bill

 

[12Footer]

Re: LOWER UNIT WHY THE BOTTOM HOLE

Yes, Lonewolf.The seal gaskets on the stainless fill & vent screws. They are as important as any other seal in the lower unit, and only cost 2 bukz for 5 of them.<br />If you don't use new gaskets after checking/filling the lower unit, it will allow water into your lower unit.<br />If you had milky lube when you first drained it, then cahnces are you WILL have to tear down the l/u and replace the seals, anyway.<br />But don't try to re-use those two small,cheap seals.<br />A good way to test the lower unit is to submerge the foot past the water intake, and pressurize it to 10PSI, using one of the screw holes (ither vent or fill),and see if the pressure drops. If it does, look for bubbles. Bubbles from the propshaft means bad prop shaft seal. Bubbles from the water intake means bad upper or water pump,driveshaft seal, or water pump-driveshaft seal.<br />You can make a tester out of 4ft of air hose,a pressure gauge,and a threaded fitting. It's kinda nice to have around when the l/u has a peanut butter milkshake in it.<br />I hope it's just a vent/fill screw gasket.

 

[MarkC]

Re: LOWER UNIT WHY THE BOTTOM HOLE

That's all good advice. Other possibilities: the seal(s) below the water pump on the vertical drive shaft; the seal on the shift shaft bushing. When you pull any of these seals, also check the shaft itself for scoring. My shift shaft was chewed up right where the seal is, and replacing the seal didn't keep it from leaking---new shaft, no leak.

 

[lonewolf5347]

Re: LOWER UNIT WHY THE BOTTOM HOLE

O.K. I2 FOOTER GOING TO PURCHASE NEW SEALS FOT STAINLEES SCREWS THER ARE 3 OF THEM , REFILL WITH NEW OIL @ SEE WHAT HAPPENS. IT MAY BE MY PROBLEM , LAST YEAR CHANGE THE IMPELLER @ MAIN SEAL THAT ATTACH HOUSING TO LOWER UNIT ; BUT THOSE SEALS ON THE STAINLESS SCREWS ARE SHOT I KNOW THAT FOR A FACT . DID NOT THINK THAT WAS A CONCERN;ALSO LIKE THAT WAY OF TESTING THE LOWER UNIT SOUNDS EASY ;DID NOT RELIZE YOU CAN USED THE VENT HOLE WITH A FITTING TO TEST UNIT ;THANKS A LOT FOR THAT INFO.