GNJ

I bought a pair of new recirc pumps for my motors and installed them during rebuild. When I purchased them, I was not aware that the serpentine belt system on my 502's actually spin the recirc water pump the opposite direction of the crank and other pulleys. The H20 temp guages were reading 160* on both motors, but when I shut them down, there was every indication that the motors were hotter than that. So I relocated the sender out of the stock Gen 6 merc thermostat housing and found the temp was
actually much higher, around 210*+. So now I'm thinking the recirc pump is pumping the opposite direction and fighting the raw water pump.

When I called the seller/distributor of the pump, he told me it was a "Bi-directional" marine pump and has sold many units with no issues. Is this possible that the recirc pump could be bidirectional? Any body agree with this?

Thanks - Gary

GSS0816

Depending if your motors are left or right hand, look on the back of the pumps and you will see how to put the hoses for either right or left hand.
Steve

GNJ

GSS0816 Motors are right hand rotation but I think you are referring to plumbing of the raw water pump not the recirc, Any body else ????

Wally

The only way a pump can be bi-directional is if the impeller blades were straight out so it wouldnt matter which direction it turned. Most i have taken appart have either curved or angled blades....now the internal design of the pump itself is another story alltogether...

PatriYacht

I'm not buying it. The only way water could move is if the casting matches the direction of water flow. Is it an OEM water pump?

GSS0816

My mistake, I thought you were referring to the raw water pumps. I agree with previous post, water pumps are usually specific(right/left hand)

suntimes

I just bought a bi-directional circ. pump as well. If it is designed to function both ways, it should work. Maybe yours wasn't built correctly? I haven't mounted it yet, so no results to report...

jmherbert

The blades in a merc pump are straight up and down.

I know because the impeller fell off one of mine and led to blown headgaskets.

Fenderjack

Yes there is a such thing as bi directional pumps. Most marine pumps that mount on the front of the engine will work both ways if it says bi directional because on inboards one motor runs clockwise and one runs counterclockwise. . Back in the day you had to tell them what direction your motor turned so you could get the correct pump. But then they came up with the bi directional pump so you could use it on either engine. A serpintine belt engine that has a standard rotation engine usually runs the engine pump off the back side of the belt (smooth side).So in that case the pump turns backwards,thus the need for a bi directional pumps.They have straight blades at right angles off the pump shaft .JOHN

offthefront

if these are standard 502's with Bravo setup they should be LH rotation .........m