It is most likely that the pumps for standard and reverse recovery continue from each other. But to be sure, you should check with your dealer or manufacturer more often to get accurate information on your engine and water-coolant models. If you have an engine serial number, you can use it to find information about the water cooling pump for your engine. This usually leads to significant results on water cooling pump installation and replacement, including how to tell the difference between standard and reverse pumps. If you don't have the ability to get accurate information about his pump, you can install a sample and see if it works in the right way. However, this can be unexpected because an incorrectly installed pump can lead to engine failure. It is best to get help from professionals who determine the right pump for your engine.

Last edited by SachinKumar (3/24/2023 8:00 AM)

Good rule of thumb with serpentine drive for Chevys is that if the smooth (back) side of the belt spins the water pump its reverse rotation.  If it has a ribbed pulley its standard.  That said, pretty sure the boat 4.3s were all reverse rotation. 

Follow-up

I looked on Amazon to compare several different water pumps.  Most said they were bi-rotational.  However, I am unsure of the one I have here, so I ordered a new pump that stated it was bi-rotational.  Problem solved.  $100 spent.  Now I have a brand new pump that I already owned that is not of much use because I cannot see if it has straight or curved vanes unless I destroy it to take it apart.  Part of owning a boat, I guess.  Bust Out Another Thousand...

MS wrote:

Follow-up

I looked on Amazon to compare several different water pumps.  Most said they were bi-rotational.  However, I am unsure of the one I have here, so I ordered a new pump that stated it was bi-rotational.  Problem solved.  $100 spent.  Now I have a brand new pump that I already owned that is not of much use because I cannot see if it has straight or curved vanes unless I destroy it to take it apart.  Part of owning a boat, I guess.  Bust Out Another Thousand...

Put the pump you're not using in the box of the pump you're using, and return it!  Sal told me to say this....

Last edited by josh-kebob (3/24/2023 4:21 PM)

MS wrote:

I KNOW the 4.3 uses reverse rotation due to the belt configuration.  The original pump I took off is externally exactly the same as a pump of unknown application I had on the shelf.  I removed the backing plate of the original 4.3L pump and cannot see the impeller vanes due to the large plate covering the vanes.

Dan, the video you posted shows there to be a difference, so I will remove that pump and go buy another one specifically for my application, even though there is a chance the one I installed might be correct.  Just cannot see the impellers like you can in that video.

Thanks for the responses.

The belt routing determines whether or not the pump needs to be reverse rotation.  My comment wasn't about your boat, I imagine you know how the belt(s) are routed on it; it was hopefully helping you identify what the pump on the shelf was for if you could remember how the belt(s) were routed on the boat which was the source of that pump.  I can't say for 4.3s specifically, but since a 4.3 is just a 3/4 350 I can say that when Chevy switched from v-belts to serpentine on the 350 they went from standard to reverse rotation water pumps.  I converted my '86 IROC from v-belt to serpentine and checked every part to verify exactly what I needed to change.  In summation, if the water pump is off a v-belt application I wouldn't use.  If it came from a serpentine belt application it should be the same. 

MS wrote:

Follow-up

Problem solved.  $100 spent.  …..  Bust Out Another Thousand...

You can send me the $900 …..to keep this true.😁

Hopefully it’s the last water pump that engine will need…until next winter?🥶