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Vacuum testing Johnson Venom 200 gear case....

D

dentpusher

New member
Hello all, new to forum.

I have a 98 Johnson Venom 200 that has some cloudiness in the grease after 3 years of service, about 15-20% of the grease had light milky haze to it. I performed a pressure test and it holds 6 lbs pressure indefinitely, at least over night. I hooked up vacuum and I get a 1 inch loss of vacuum in 5 minutes. My question is, is there an acceptable rate of loss or should it hold vacuum indefinitely like it does pressure. Or is there a specific rate of acceptable rate of loss like 1 inch per minute?

Thanks for the help,
Dave
 
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No acceptable rates of loss are published.
But from experience, that's too much loss.

Also, I pressure test to about 12-14 lbs and expect it to hold all night. Six is too low.
 
Thanks! That was the spec SELOC manual had. So much for that thing. The info there is WAY generic...

Follow up: We are heading to the lake next week for our summer week at the lake. With that rate of loss, and knowing that is something can go wrong-it will, would you put gease in it and head out to perform repair after returning OR does it need it right now? I have the OEM seal kit on hand but things rarely go smoothly for me the first shot....

Also, what are alternatives to J/E Gasket sealing compound? I have heard Permatex Aviation gasket sealer(non-hardening) but was leaning toward Permatex Ultra-Grey silicone, as it is for rigid joints in high torque, high vibrations applications and is spec for many auto manufactures now.
 
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There should be no vacuum loss at all nor should there be a loss of pressure. I test mine to 15 PSI. Permatex aviation works well for the seals and RTV for the RBC O ring black or blue just let it tack. Don't forget the shift rod O rings inside the shift rod cap.
 
Re-sealing the gearcase is not a really simple task. Especially if you have not done one.
Getting the propshaft carrier out is difficult.

Anyway, it is probable that you will get the case torn down, and then not get it back together in time for your trip.
So, if it were me, I would change the gear oil, use the boat, and try to get the foot out of the water by tilting up or trailering it
so the foot is not submerged.

Then come back and do the re-seal job. Use Permatex Aviation as a substitute for OMC Gasket sealing compound.
I do not use any RTV silicone compounds on any outboard parts re-assembly.
 
Removing the RBC isn't really that difficult, a few simple tools, a harmonic balancer puller, and two pieces of 5/16" all thread, four nuts to make up some jam nuts and two decent size washers. Remove the bolts and locking tabs for the carrier. Slip the all thread into the Harmonic puller and use the center bolt to remove the carrier. Use a seal puller to remove the seals and a small flat blade to remove the O ring. Coat the outer edges of the seal/seals and use a suitable size socket to drive them in. ALL OMC/BRP manuals call for RTV to be applied to the aft support area of the RBC. Triple guard grease should be applied to the inner lips of the prop shaft seals.
The nylon washers on the drain and vent screws should be replaced also. Dropping the LU isn't that hard of a job especially if you remove the port side belly pan to access the shift rod pin. If you have any type of mechanical skills you can do the repair using your Sealoc manual in 4 hours and that is being generous.
If you have to drop the lower then it would be a great time to replace the water pump as a kit..
 
Thanks fred, I am pretty mechanical and have done seals on car axles etc before so I am not too worried. I already have the LU off for a new water pump. I have a small engine flywheel and a steering wheel puller that I figured I can rig to work. I am just debating on doing now with short notice IN CASE something goes wrong... Can you explain where the RBC aft support area is? And is Aviation sealant a substitute for Gasket compound?
 
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I just use OMC Triple Guard grease on the orings, and I make sure the o-ring mating surfaces are very clean.

Re: ease of job.....I have to disagree. If this is a salty, like I work on almost exclusively, the bearing carrier can be so stuck that it breaks
even the stoutest of pullers.
I have used the method described above but with homemade pulling hooks made out of 1/2" steel rod, bent at more than 90* to hook behind the carrier webs.
They bend. Straighten right up. So it ain't easy all the time.
Most of the time, I have to use heat just to get it started. This job can be very difficult, especially for the first timer.
And then, there are the cases where the carrier breaks. So...judge for yourself the difficulty.

Panhandle Fred......hmmmmmm. Ah yes.......maybe freshwater Hartwell motors are not as stuck and corroded.
 
My motor has been exclusively fresh water and only SLIGHT oxidation in one area around a small weep hole or something on the starboard side of unit.
 
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Yep sometimes you have to heat and beat. No longer on the shores of Lake Hartwell, now residing in the Big Bend of the Gulf. The old dog still knows a few tricks. :)
 
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