Alpha 1 Gen 2 Pressure test unable to

[Boatrunner1]

Just got a 1995 Larson Escapade 240 with a mercruiser 5.7L alpa 1 gen 2 drive. The gear oil resevoir empties after about 20 minutes at idle. No gear oil in the bildge but a gear oil slick comes from the outdrive into the water. I drained the gear oil out of the drive and got about 3/4 of a quart and it was not milky.
I attemted to do pressure test of the drive while it was still hooked to the boat. I removed the hose from the resevoir and plugged if first before i tried to pressurize the drive. I hooked up the air source to the vent hole and put the screw back into the drain hole before I tried to bring the drive upto 15 psi.
when i applied the air pressure the pressure gage remained on zero and the drive did not pressurizs at all! I could hear the air going into the driveclose to the vent hole where the air feed was hooked upto, but the guage would not come off of zero psi....
The only thing i can think of to get zero pressure with the drive hooked up and the resevoir line plugged is that the hose from drive check valve that goes thru the hull is disconnected or broken.
Next chance i get i will pull the drive off and do a pressure test to see if it will move the pressure guage off of zero psi.
Any thoughts?
Thanks in advance!

 

[Bt Doctur]

remove the drive and retest

 

[harringtondav]

Late night brain flatulence here. Refill your drive with any type of oil. Put the cap back on your reservoir. It has a cap check valve to hold pressure. Do your pressure test again on a trailer or on a lift. Watch where the oil emerges. Sounds like you have a gushing artery, so you should be able to see where it is originating. If it flows down the transom area suspect a bad lube hose fitting or hose between the gimbal hsg.and bell hag. If around the drive- bell hsg. joint, maybe a bad bell hsg. gasket. If between the upper and lower drive hsg. joint, possibly an omitted or bad quad ring on the lube passage between the two hsgs. If out the prop, bad seals on the lower unit drive shaft seals, or a displaced seal carrier under the water pump. If none of these, pull the out drive per Bt Doctur and see if the if the drive shaft bellows is full of oil. Then refill and pressure test again per the Doctur. All my steps above will smoke out a leak before the bell hsg. check valves.

 

[Oshkosh1]

I tried to pressurize mine last week but could not. Looked everywhere but couldn't find a leak. All I knew is that it was leaking out even though it looked fine when I drained it. Found after spraying soapy water around that it was the upper driveshaft seals. Took it to the local shop and had them replaced to the tune of $145. Same engine/same drive other than mine does not have the reservoir but a dipstick on top of the drive...

 

[tpenfield]

:welcome:

As stated, remove the drive, drain the gear oil and re-test at about 10 psi. Use the soapy water trick around the drive shaft, prop shaft and oil plugs and look for the growing bubbles.

 

[harringtondav]

:welcome:

As stated, remove the drive, drain the gear oil and re-test at about 10 psi. Use the soapy water trick around the drive shaft, prop shaft and oil plugs and look for the growing bubbles.

Yes. 10 PSI is the spec. If you go much over this you run the risk of blowing the seal carrier under the water pump up out of it's bore. I did this once.

 

[wellcraft-classic210]

Once you pull the drive -- finding the leak will be easier -- Big leaks are easier to find.

I once dunked mine in the kiddie pool to find a slow leak on the shift shaft .

 

[Boatrunner1]

Thanks for all your responses... Today I puled the drive off and the gimbal bearing bellow had gear oil in it. The good news is that the oil was clear and there was no water in the gimbal bellow.
I just attempted to pressure test it and as soon as air was supplied thru the upper vent tube air was hissing and a little remnant oil was "gurgling"from the ares behind the drive shaft yokes.
It sounds like it is the same problem that Oshkosh1 had if that is where the upper drive shaft seals are.
Is that the only seal in the upper part of the drive?
Thanks again....

 

[harringtondav]

That's the only seal around the yoke. But an oil slick in the water means other seals may also be bad. May be time for a complete seal job.

 

[achris]

That's the only seal around the yoke. But an oil slick in the water means other seals may also be bad. May be time for a complete seal job.

+1. At more than 30 years old and probably with at least 2000 hours, time for a full strip, clean and reseal. Pay particular attention to the seal surfaces on the shafts. Any with deep grooves will need to be replaced or sleeved. Also check and adjust the preloads on the top housing bearings, and the top bearing in that housing is most likely going to need replacing. ..

Have fun.

Chris. ...

 

[harringtondav]

Pay particular attention to the seal surfaces on the shafts. Any with deep grooves will need to be replaced or sleeved.

I've cheated and sneaked by shaft grooves by putting .040-060" shims under the setting face of my seal drivers. This sets the seals into fresh shaft surfaces. This is a limited cheat. Sooner or later you will run out of usable seal bore length.

 

[achris]

I've cheated and sneaked by shaft grooves by putting .040-060" shims under the setting face of my seal drivers. This sets the seals into fresh shaft surfaces. This is a limited cheat. Sooner or later you will run out of usable seal bore length.

That's exactly what I also recommend, and do, for 'repairing' that particular surface. Just get the new seal onto a new, unused, section of the shaft and it's just as good as a new one.

Chris......

 

[Boatrunner1]

Ok... Thanks for the input! I will be putting it in the shop for repair this weekend and hoping for the best! The hour clock on the boat read 611 hrs. when I got it and it now reads 614 hrs which averages out over 23 years to be only 27 hrs. of use per year so hopefully its only the top end drive shaft seal and in the worst case a few more seals, and no major damage in the out drive.
When it was in the water running, driving it at idle speed at first, and then for a little while at 2000 rpm, the engine was purring like a cat and no strange noises or behavior coming from the outdrive..
I'll tune back in after its all said and done and let "you guys" know what the final outcome was...
I really appreciate this forum, as I have been reading it the last couple of years as a guest learning about the 3.0L mercruiser I had on my previous 19 ft. Maxim!
Thanks again

 

[Boatrunner1]

Back in business! The shop replaced all the seals and o rings in the upper drive. At the end of the season I will get the same done for the lower half to give me peace of mind and a fresh start knowing the condition of my outdrive.
Thanks for all your words of wisdom!