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Gear oil in bilge....

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russray

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I bought a little 17 foot runabout with a 4.3 merc I/O. I tested the motor and outdrive with motor muffs and everything ran fine. So I take it to the lake the next day and run about half a tank of gas through it and it performs well. I load the boat back on the trailer, take it home and the next day I find a little bit of oil in the bilge. I'm thinking this cannot be good. Today, which is several days later I look in the bilge again and it is full of oil! I haven't checked yet but it looks like ALL the gear oil is in the bilge. How in the world does the gear oil find its way into the bilge with the bow up and the engine not running? It is a 1988...it doesn't have a reservoir, just what's in the outdrive itself.
 
It's possible gear lube is leaking past the seals on the driveshaft yoke.Pull the outdrive and see if the driveshaft bellows got gear lube in it.
 
Either as mentioned above or the lube resevior and associated hose and fitting are leaking these go from drive bottle to transom fitting . Follow the hose look for leaks
 
Dieter said:
Either as mentioned above or the lube resevior and associated hose and fitting are leaking these go from drive bottle to transom fitting . Follow the hose look for leaks
Click to expand...
It doesn't have a reservoir....so I can scratch that one off the list.....
 
russray said:
It doesn't have a reservoir....so I can scratch that one off the list.....
Click to expand...
Ok then shaft seal on Input shaft would be it if it is gear lube. If u have lost that much oil out of the drive that your bellows are full and dripping in the boat top off the drive before use. Without the gear lube reservoir if u loose lube into bellows ur upper headset and bearing will run dry and self destruct take drive off and pressure test


Would also check that it isn’t engine oil, ps fluid or drive trim oil. The hoses from trim pump go into bilge
 
Dieter said:
Ok then shaft seal on Input shaft would be it if it is gear lube. If u have lost that much oil out of the drive that your bellows are full and dripping in the boat top off the drive before use. Without the gear lube reservoir if u loose lube into bellows ur upper headset and bearing will run dry and self destruct take drive off and pressure test


Would also check that it isn’t engine oil, ps fluid or drive trim oil. The hoses from trim pump go into bilge
Click to expand...
I don't plan on running drive train again until I figure this out.....I drained the oil out of the lower unit and I got about 1/2 a quart!
 
With all the gear oil drained, You should remove drive from boat.

The drive should be pressure checked. If you are unable to do so you will need to have it done.

If you can do this yourself, use either drain or vent hole to install hand pump for pressure check. Pump pressure to ~15psi. Listen for leaks.

The following link shows the upper gear case assembly.

Item 18 is a large O-ring and should be replaced.

Item 20 is the upper carrier seal and is most likely your issue. This seal, seals to the Yoke assembly (item 11).
(NOTE: after years of use it creates a deep groove and it may be difficult for the new seal to seal to yoke. A quick fix is to move seal within the carrier ~1/16" to seal to clean metal surface.)

Item 19 is the carrier assembly with the seal installed (item 20). Best to buy this assembly of you cannot press old seal out and new seal into carrier.

MerCruiser R / MR / Alpha One (Sterndrive) 1983-1990 Driveshaft Housing & Drive Gears Parts

MerCruiser r/mr/alpha one (sterndrive) 1983-1990 driveshaft housing and drive gears parts. Buy a genuine Mercury Quicksilver or aftermarket part.
www.marineengine.com www.marineengine.com
 
kghost said:
With all the gear oil drained, You should remove drive from boat.

The drive should be pressure checked. If you are unable to do so you will need to have it done.

If you can do this yourself, use either drain or vent hole to install hand pump for pressure check. Pump pressure to ~15psi. Listen for leaks.

The following link shows the upper gear case assembly.

Item 18 is a large O-ring and should be replaced.

Item 20 is the upper carrier seal and is most likely your issue. This seal, seals to the Yoke assembly (item 11).
(NOTE: after years of use it creates a deep groove and it may be difficult for the new seal to seal to yoke. A quick fix is to move seal within the carrier ~1/16" to seal to clean metal surface.)

Item 19 is the carrier assembly with the seal installed (item 20). Best to buy this assembly of you cannot press old seal out and new seal into carrier.

MerCruiser R / MR / Alpha One (Sterndrive) 1983-1990 Driveshaft Housing & Drive Gears Parts

MerCruiser r/mr/alpha one (sterndrive) 1983-1990 driveshaft housing and drive gears parts. Buy a genuine Mercury Quicksilver or aftermarket part.
www.marineengine.com www.marineengine.com
Click to expand...
Sounds great! Thanks....
 
I'd take the top cap off of the upper drive...if the gears/bearings went because of the lose of oil, no need to pressure test...
 
kghost said:
With all the gear oil drained, You should remove drive from boat.

The drive should be pressure checked. If you are unable to do so you will need to have it done.

If you can do this yourself, use either drain or vent hole to install hand pump for pressure check. Pump pressure to ~15psi. Listen for leaks.

The following link shows the upper gear case assembly.

Item 18 is a large O-ring and should be replaced.

Item 20 is the upper carrier seal and is most likely your issue. This seal, seals to the Yoke assembly (item 11).
(NOTE: after years of use it creates a deep groove and it may be difficult for the new seal to seal to yoke. A quick fix is to move seal within the carrier ~1/16" to seal to clean metal surface.)

Item 19 is the carrier assembly with the seal installed (item 20). Best to buy this assembly of you cannot press old seal out and new seal into carrier.

MerCruiser R / MR / Alpha One (Sterndrive) 1983-1990 Driveshaft Housing & Drive Gears Parts

MerCruiser r/mr/alpha one (sterndrive) 1983-1990 driveshaft housing and drive gears parts. Buy a genuine Mercury Quicksilver or aftermarket part.
www.marineengine.com www.marineengine.com
Click to expand...
What link?
What are the Item Numbers listed???
 
●Oil drained.
●New Gear Oil Regulator/Reservoir Cap with rubber Washer is ON.
●New Outdrive Gear Oil hose/line is installed and NOT showing an air leak with soap water at the transom or lower unit.
●Outdrive exterior gaskets show no air leaks with soap water.
●Oil drain/Fill plug bolts show NO air leak with soap water.
● Bilge Transom Gear Oil hose to Resivoir shows NO leak with soap water.
Pressure tester WILL go to 15psi, but drops to 0 in 30seconds.
WHAT ELSE IS THERE TO CHECK?
 
When doing a preasure check with remote resevoir you have to pinch off the oil line just behind bell housing. I use vice grips with the jaws heavily taped with elec tape so not to damage hose.

If you dont, all the pressure escapes from resivoir vented cap.
 
I didn't think about that bc I figured the rubber Washer in the cap would Seal the air flow.



You're saying the Cap WITH the rubber washer does NOT create an air Tight seal?
If so, I believe my issue is probably fixed; bc I literally just crawled out of the Bilge with a flashlight and soapwater spray bottle, and I didn't see 1 Single bubble.
 
What happened to the OP? Hey Cmfn1995Chaparal, you should start your own thread about your specific problem. It can get confusing when there are two people asking about two different boats in the same place.
 
As mentioned cap is vented, pinch the line and retest. Would also lift the drive and put soapy water on the shift shaft common leak place
 
The aftermarket yoke is fairly inexpensive (as boat parts go) at $94. If yours is worn out I'd pop for a new one.
 
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