DD 6-71 Governor type/model?

Usually a single weight, variable speed, mechanical governor.
The serial number or tags will offer the best data.

Why are you wanting to replace it?

'81 serial numbers for 671s started at 6A414833. look for a number starting with 6A.

May be the marinizers (JT, Convington, etc) serial number

3 bearings and what problems? There are some adjustments.

Those are usually adjustable symptoms.
Possibly, the loaner governor was already closely adjusted. Likely the next (used or rebuilt) will need to be set up and adjusted in anyway.

When running, you set the throttle to 1600 rpm and it stays there, there in not a governor issue.
If it hunts for idle, the rack is binding or the buffer screw needs a twist.
A non running 2 stroke, the rack is open when not running. If you have to open the throttle to start, the rack is binding.
A binding injector may cause the same symptoms.

Of course, I'm not there hands on. There could be some drag (lock up) in the governor that may cause some issues. Not to say it's not possible, I've never had my hands or eyes on it before.

Just be careful when throwing money at a problem. You could induce new symptoms.

,rc

1600 was my good example number. If the governor holds any same rpm up and down hill (swells), then it's governing. *
The governor holds the engine speed as directed. It does not hold the throttle lever in place.
If your throttle lever moves while running, there is another adjustment for that.


*Hence the term variable speed, You set any engine speed, the governor will hold it there.

After replacing the governor, there is about a half dozen adjustments to be made after the control rod and racks are proved smooth and not binding. This may require the valve cover removed. A floating, smooth and free complete travel on the control tube is important before any governor adjustments are done.
Light her up (with vice grips on the shutdown lever for added leverage), Find some kind of course idle, course throttle assist spring adjustment and shim up the WOT / Max rpm / no-load rpm.
Then fine adjust the throttle assist spring, idle, idle buffer. Then put on the water skis and go.
Details are in the DDC manual less the vice grips.

No stuff, Big set of vice grips on that shut down lever is important just in case....

If there is not a core return required, mail the old one to me.

Off of his engine of from a spare shelf?

Now that's a friend.