Alpha one Lube alarm

There should no oil contamination within the reservoir.

The drive will undergo a mild pressure increase (due to expansion) as temperature rises.
This will generally push some gear oil back into the reservoir, as intended.
Conversely, as the drive cools, oil returns to the drive, and pressure again balances and remains neutral.
(pressure never actually increases/decreases..... as the reservoir balances this out)

If the oil within the reservoir is becoming contaminated, then the oil within the drive is likely contaminated also...... or has been in the past.

You may want to perform a Pressure/Vacuum leak down test.
(reservoir line must be pinched off)
The pressure leak down test requires that the drive be drained of gear oil.

Merc suggests not doing a Vacuum test, but IMO, this can be done.
The difference between Press/Vacuum tests re; the vacuum test, is due to the nature of the several single lip seals.
This style seal does well against positive pressure, but not so well against negative pressure.
The vacuum test can serve as an indicator,.... just note that the "leak-down" holding ability (psi -vs- inHg) may not appear equal.

.

gcdb said:

Dear all, new user, this may have been covered before, apologies if so. Mercruiser 4.3 V6. Alpha 1 Gen 2 SD. Lube level audio alarm sounding whilst on the water the other day and, whilst checking on the muffs out of the water since, it has done so occasionally at start up, but not every time. Level in the reservoir is good, lube out of the bottom screw on the drive looks clear and blue. There is however a grey sludge layer (7mm) at the bottom of the refill reservoir on the engine. I replaced the lube in the drive 6 months ago with the impeller, but not in the reservoir (Clamped this off whilst changing impeller), so this is older lube. ...is this just dirt in the reservoir and needs removing, emptying and a clean or a more worrying sign? Thankx for any help/advice GB

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Are you sure the alarm was set off by the drive oil sensor? If you disconnect the wires on the sensor does the alarm go off?

Many thanks,

Chris:I assumed it is the lube alarm, having rifled through the Merc manual i can only find the lube causing the intermittent Audio alarm, the other continuous alarms are catstrophic stuff going on.

I wondered if it was the gunk "Fooling" the sensor that the level was low.

As i say, it is not always reproducible, so taking the sensor off may give a false negative, if you see what i mean...but will try

What else will cause the intermittent audio alarm. I did notice the Speedo drop to zero (even though still on the plane) shortly after the alam started sounding...?related.

Rick: Pressure testing, something for a novice or into the Merc dealer for this? Any harm/risk in me draining the whole system, resevoir included, cleaning the resevoir and refilling the drive and resevoir and seeing what happens?

Thanks guys

As for the alarm, The low oil pressure switch, drive oil level sensor and temp switch work off the same wire circuit. It is a grounding circuit. If any of the three ground, the alarm will go off. What temp are you running when the alarm sounds?

Temp was 220 (I think), either way half way up the temp dial-(perhaps 175?), normal running temp for the boat since i've had it for 50 hours. Oil i check each outing and has been OK, Oil gauge was OK too (same as always, can't give you a number).

One other thing i now rememeber, i randomly topped up the lube oil (half way between the 2 levels) before we headed back (15 min run home, alarm sounded 3 mins from home) having used the boat during the day...perhaps this might have caused an issue?

Thanks for the help

Any loss of drive oil means there is a leak. Drain the OD including the reservior (clean it) and pressure/vacuum test as previously advised. Check the drive oil for water (salt?) intrusion. Inspect the magnetic drain plug for metal frags, shavings, etc. Dark goo attached to the plug is normal while the aforementioned are signs of gear degradation. Inspect the reservior switch/wiring for corrosion. Remove the prop and inspect the shaft seal for fishing line...if you find some the shaft seals may have been compromised.

gcdb said:

Rick: Pressure testing, something for a novice or into the Merc dealer for this? Any harm/risk in me draining the whole system, resevoir included, cleaning the resevoir and refilling the drive and resevoir and seeing what happens?

Thanks guys

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Should be no harm in draining the oil.
You're more likely to make a mistake when re-filling it. See the OEM instructions.

Doing the leak-down test is easy and simple when you have the correct test equipment.
Tom Green offers a nice and yet inexpensive system. [email protected]

Looks like this:

gcdb said:

Temp was 220 (I think), either way half way up the temp dial-(perhaps 175?), normal running temp for the boat since i've had it for 50 hours. Oil i check each outing and has been OK, Oil gauge was OK too (same as always, can't give you a number).

One other thing i now rememeber, i randomly topped up the lube oil (half way between the 2 levels) before we headed back (15 min run home, alarm sounded 3 mins from home) having used the boat during the day...perhaps this might have caused an issue?

Thanks for the help

Click to expand...

If the engine is not Fresh water cooled, It's running too hot and tripping your alarm. Forget about the drive oil, it's not your problem.

Welcome aboard. I agree that if the temp is 220, it's too high. You must confirm if this is what you're running at. If so, that's most likely the issue. All the same, clean out the reservoir, that goop in the bottom tends to cause your float to stick eventually. Keep us posted.

Thanks to all

Have checked running temp...175, NOT 220, oil at 40.

Sea water cooled, flushed on the muffs after each outing.

Will drain drive (check the plug and state of lube as suggested) and reservoir and clean this out.

Check connections

Will check prop for line.

Will try and find a pressure kit (unsure in these parts where from).

Refill.

Ricardo: what can i get wrong refilling you mention more likely to make mistakes with this part???

...and see how we get on

Once again, thank all, V helpful

GB

Come on guys. Dirt in the lube reservoir will not cause an intermittent alarm.
If it's Raw water cooled the t'stat should be 160 degree. 175 degrees will trip the alarm. Disconnect you lube level sensor and run the boat. Bet the alarm sounds.

Thanks Chris

I'll give it (all) a go

Cheers

Chris, I agreed that it's a temp issue. I also simply stated that he should clean out the bottle to prevent the float sticking in the future ("eventually"). I've seen the goop so thick there at times that it would prevent the float from rising once it touched the stuff. Not saying that is the case now, just getting him to be proactive.

Ditto being "Pro-active".

gcdb said:

Ricardo: what can i get wrong refilling you mention more likely to make mistakes with this part???

Click to expand...

GB, sorry if that confused you.
It was a rather general statement in that draining the gear oil will be pretty straight forward.
When you pump the new gear oil in, just follow the OEM instructions.... open the vent, pump oil, allow a few minutes for any air to breach, close vent, install drain plug with new gasket/O-ring!

NOTE: some of us use a hand held impact tool for the "set" of this drain plug..... a few mild (Mild being key word here) blows on the impact tool sets this much better than if by screw driver.... IMO.

Perhaps run the engine on the garden hose, shift in/out of gear....shut down...., check level once again.

Those are just a few suggestions!
Your call on that!

Dear all

Thanks for all the advice.

No matter what caused the alarm, the slight milkiness to the Gear oil and perhaps the sight of small metal particles on the plug have caused me alarm...so worth draining it...

Boat's going to the shop in 24 hours...along with my wallet...

And so the money pit begins....

Cheers

GB

When you changed the impeller and refilled the outdrive did you fill it up from the top screw or the bottom screw on the outdrive?

If you drained it from the bottom and filled from the top then this may be why you have issues......Just a guess........

Thanks

Filled it bottom up.

Anyway it's due a service in 20 hours so will get it all done now, getting warmer here so peace of mind for the Easter.

Keep you posted

GB

Back from the shop last week. Water in the lube, gears all ok, new lower unit seal kit and full engine service.

Not had the weather to test on the water yet, but fine on the muffs at home.

Still not really sure what was causing alarm, but will see what the temps like on the water next week.

Thanks for all the input

GB