Flushing Alpha drive.

[fdnylou]

New to boats, have a merc Alpha drive. Mechanic told me I can't use fresh water hose with muffs to flush out salt water. Anyone ever hear of that ?

 

[Bt Doctur]

not knowing your cooling and plumbing thats hard to confirm. but you can use a hose connection if done properly and if the drive supplies water to the engine. Some systems use a engine driven pump and seacock

 

[RicardoMarine]

New to boats, have a merc Alpha drive. Mechanic told me I can't use fresh water hose with muffs to flush out salt water. Anyone ever hear of that ?

NO I have not!

One of two things has likely occurred:
You have either misunderstood the mechanic, or the mechanic is inexperienced.

With the garden hose attached to the water muffs, water muffs properly attached to the lower unit, and with the water supply on, you can start and run the engine. You should see water exiting the exhaust area fairly soon.

If your engine is Raw Water Cooled, keep in mind that most all water is being directed to the exhaust system.
The cylinder block/cylinder heads will only see fresh flushing water as per the thermostat's open position (I.E., as the engine reaches operating temperature).
What this means is...... when you see water exiting the center of the propeller (or via the exhaust relief area), it is NOT an indication of a full flow flush.
You must operate the engine for a period long enough to have allowed the T-stat open position to pass enough water to ensure a good flush.
At low idle speed (no load) the engine will not produce much engine heat (required for thermostat to open), so you may need to operate the engine for 10-15 minutes or so.


If your engine is fitted with a Closed Cooling System, the above will not necessarily apply.
The fresh water will first pass through the seawater side of the Heat Exchanger and will then go on to and out the exhaust system.


Bottom line...... yes, you can flush out while on the garden hose and water muffs!





.

 

[fdnylou]

NO I have not!

One of two things has likely occurred:
You have either misunderstood the mechanic, or the mechanic is inexperienced.

With the garden hose attached to the water muffs, water muffs properly attached to the lower unit, and with the water supply on, you can start and run the engine. You should see water exiting the exhaust area fairly soon.

If your engine is Raw Water Cooled, keep in mind that most all water is being directed to the exhaust system.
The cylinder block/cylinder heads will only see fresh flushing water as per the thermostat's open position (I.E., as the engine reaches operating temperature).
What this means is...... when you see water exiting the center of the propeller (or via the exhaust relief area), it is NOT an indication of a full flow flush.
You must operate the engine for a period long enough to have allowed the T-stat open position to pass enough water to ensure a good flush.
At low idle speed (no load) the engine will not produce much engine heat (required for thermostat to open), so you may need to operate the engine for 10-15 minutes or so.


If your engine is fitted with a Closed Cooling System, the above will not necessarily apply.
The fresh water will first pass through the seawater side of the Heat Exchanger and will then go on to and out the exhaust system.


Bottom line...... yes, you can flush out while on the garden hose and water muffs!





.

thank you , the boat does have a raw water intake , from what I can see and read from online manual it’s for the cabin a/c cooling heating unit . Doesn’t go into engine. That’s what I think this “mechanic” thought that was . Also can I flush it in the up position? Will be at boat slip . Thanks again

 

[Bt Doctur]

outdrive must be BELOW the upper trim limit to not cause U joint damage. You CANNOT run a motor with the drive fully up.
Now if you tell us what you have we might be able to have better answers instead of "New to boats, have a merc Alpha drive"
If you dont know exactly what you have there is a small tag just above the starter ,post those numbers and some pics too.

 

[RicardoMarine]

.....................

thank you , the boat does have a raw water intake ,
Most any stern drive will offer a raw water (aka seawater) intake area.

from what I can see and read from online manual it’s for the cabin a/c cooling heating unit . Doesn’t go into engine.
You lost me on that one!
I thought that your thread was asking about flushing the drive and engine!

That’s what I think this “mechanic” thought that was .

Also can I flush it in the up position? Will be at boat slip .
A few things to note:

.....When a drive is in the Full Up position, the universal shaft will be articulating near it's maximum angle. While I believe that it can handle a short duration of low RPM, it is not recommended.

....When a drive is in the Full Up position for extended periods, the bottom side of the drive shaft bellows is being put under unnecessary stress. While it may appear to be a good position for storage, you will extend the life of the bellows if you leave the drive fully down and aimed straight FWD! (you will NOT see any mention of this in any OEM or non-OEM service manual)

......The A drive's seawater pump is located in the lower gear unit. If a flushing kit (Perko Flush Pro for example) is to be added, the seawater pump flow must be diverted during usage. It can be done, however, the kit does not allow for potable water flushing the actual drive. Engine and Exhaust components ONLY.