2011 250 Pro XS 250 lower unit won't hold pressure

[gambler1]

Serial #1B561905
So quick run down, went fishing and when I pulled the boat out at ramp noticed a wad of braid fishing line wrapped around prop.
I pull prop off and remove what would compare to an Osprey nest on prop shaft and prop.
No sign of any leakage with the motor trimmed down overnight but decided to take it in to authorized Mercury dealer near me
to change out gear oil and double check for seal leak. Good part was on the oil drain no water in housing, But he is telling me that during pressure test
it would not hold 15# of pressure and I have a leak somewhere and would only hold about 8-10# of pressure.
Now I'm no Merc mechanic by any means but can someone tell me how you can apply air pressure and not see oil coming out somewhere during process
if there is a seal leak? To find the seal leak he tells me 4-5 hrs labor plus parts to determine problem because he has to take lower unit off and open up and suggested water pump replace, impeller,
and all seals. I feel like I am getting hosed here and looking at $6-900 to replace seals due to fishing line. Remember there was no water in oil at time of drain or any oil leaking out of unit. Why 8-10# of pressure and not 0 if a leak?
Am I out of line or is the normal cost and procedure taken? Will insurance take care of this issue?

[Gamblinman]

For a thousand dollars, I would not file a claim with insurance. Save that for a major repair.

[06 SB]

It is the price to pay for our hobby. I would not go through insurance either. $900 is not out of line either. Have you looked to see what a replacement LU is going to cost if it were to grenade?

Here is a quote from Don on a thread where my son hit a small log while running that may help. I have a pressure tester and was going to check it myself. Mine failed...

-Kiddie Bubble Mix make s a GREAT leak checker

-Test at several different pressures (example: 2, 6, 10, 14 (max) psi).

Some seals may leak at lower pressures, but not at higher pressure (or just the opposite).

[greg88]

I had A lower unit completely resealed and it didn't cost near that a few years back.

[EuropeanAM]

1. Gear lube is drained before performing a proper Pressure Test.

2. Seal leaks are located with soapy water (which causes pretty bubbles to appear where leaks are).

3. Flat rate time for resealing is under 3 hours labor. Add a reasonable amount for diagnostic time, and multiply times labor rate.

4. Cost of seal kit, impeller, and gear lube.

5. Sum of the above amounts should be pretty close to your subtotal.

(Do your own math for this... since we don't know your shop, their labor rate, or parts prices).

Very likely that the leak is coming from the INNER Propshaft seal.

[Bob G.]

I had my lower unit pressure tested 6 years ago at a shop, but I took the lower unit off and took it in near the end of winter. Seal and water pump replaced for ~$100. I recently put together a pressure tester and will be testing mine this Spring when I remove the lower unit to replace the impeller.

[Bob G.]

It is the price to pay for our hobby. I would not go through insurance either. $900 is not out of line either. Have you looked to see what a replacement LU is going to cost if it were to grenade?

Here is a quote from Don on a thread where my son hit a small log while running that may help. I have a pressure tester and was going to check it myself. Mine failed...

What failed? The lower unit pressure test?

[06 SB]

What failed? The lower unit pressure test?

The pressure test failed. It would not hold anything above about 3psi.

[Bob G.]

The pressure test failed. It would not hold anything above about 3psi.

Gotcha!

[OldTimer57]

Thing is, that might not have been caused by hitting the small log. Could have been the seals were just failing slowly and you caught them prior to serious failure by testing. They are rubber, which ages, gets hard, cracks and leaks. Slowly at first, unless you suck in a bunch of fishing line and let it get under the prop shaft seals. Particularly important to know which seal(s) were leaking. IE shift/driveshaft seals are not likely to be affected by hitting a small log. But neither is the prop shaft seal for that matter.

[tomloans]

Did they have the lower unit off when pressure testing? There are two seals on the top that can only be seen when you have the lower unit off. The braid may only be a coincidence and your real issue could be the drive shaft seal or the shift shaft seal. These two are easy to handle yourself. I wouldn't automatically assume prop shaft.

[gambler1]

Got the leak fixed and you are correct, both driveshaft and shift shaft seal needed replaced.
New waterpump, impeller and lube and back in business.
Bill was $657.00 I feel better now that it's repaired and the wrapped up braid was unrelated to my leak issue. Thanks for you help everyone.

Did they have the lower unit off when pressure testing? There are two seals on the top that can only be seen when you have the lower unit off. The braid may only be a coincidence and your real issue could be the drive shaft seal or the shift shaft seal. These two are easy to handle yourself. I wouldn't automatically assume prop shaft.