Hi Lyle,,that's not as straightforward as it should be.

First off,,,,,EQ1's are not even close to MR301's.
They have a totally different layout,,,
and will NOT fit onto a MR301 Board..
Scratch them off the list of possibilities.

............................................................................
About Your MR301-N9-1A4

"MR301" is the basic Type/Style/Package Layout.
There's a variety of suitable replacements which are
Direct FIT.
They'll "Plug-In" to your board.(solder in ,actually)

The "1A4" is a designator meaning NO="Normally Open".
That's Not an industry standard code,far as I know.
But it's Commonly Used often enough so that when we see it on Relays,,,it's a safe assumption.

The 9 in "N9",,,hmmmmm.???
It's a Good GUESS that indicates 9Volt.
It Probably means 9Volt.
But thats Not absolute Certain.

The "N" in your part number designates NON-Standard,Custom Specs.

Which is an UNKNOWN,,,and Probably Impossible to get that info from NEC or Kawasaki.

That "N" means " NUISANCE",,,lol.
Because we Dont Know,,and cannot find the Actual Specs & Info.

It introduces a Variable that really can only be determined by Visual Inspection and Testing the Relay and the Board with a VOM to determine exactly what's what.

..............................................
A MR301 is a 5-pin SPDT Relay
Single Pole,,,Dual Terminal.

The Customization MIGHT mean its 4-Pin SPST version????
It also may involve which SIDE of the Relay the Single Terminal is on.

So in order to Get a Relay which is USEABLE,,,,
It's POSSIBLE that it may require using Jumper Wires to get it Mounted and Connected Properly.

Example:
IF,,it is a SPST and has the Single Terminal Pin on "wrong side"

*Solder a wire to Pin
*Fold Pin Flat against Relay & Pointing out from under the Relay
*Solder other end of wire to Board and bend it flat against board
*The Relay will be "Tilted Up" a little on that end,,from "sitting on" the jumper wire,,,
But Opposite end the original pins will be soldered as-normal & everything will be Plenty solid
*Make a U-bend in the wire to make it easy on yourself,,some extra "working length".

That MAY not be required,,,,or maybe so.
Just no telling till you determine Board and Relay's actual pin assignment.

Polarity on the Coil terminals doesnt matter.
It just creates an electromagnet when activated.
The N~S Polarity of the magnet will change with reversed polarity,of course.
But all the Relay cares is that it's a Magnet----the Moveable PolePiece is "just Iron" and has No Magnetic Polarity.
So it's insensitive to the electromagnet's polarity.

.....................................
Here's a Schematic of MR301's

Diagram is on Page 8.
You can see in
"SCHEMATIC (BOTTOM VIEW)" it's a SPDT Relay.
SP= Pin #1
DT= Pins # 4 & #5

Recall that Your "1A4" Version is PROBABLY a SPST/Single Terminal.
Which means # 4 OR 5 would be "Missing".

And which one happens to be Missing Compared to a Replacement part will determine whether you need to Jumper Wire it or not.

http://www.ortodoxism.ro/datasheets/nec/EP2-B3N3S.pdf

.......................................................................
Here's you're Replacement Part.

4-Pin SPST which I beleive is what You'll need
(Though remember,,I cannot be CERTAIN without seeing it or knowing current part's pin count,,,,
NEC # "1A4" "SUGGESTS" this is probably Correct)

Schematic on Page 4
http://oeiwcsnts1.omron.com/pdfcatal.nsf/PDFLookUpByUniqueID/64AC57FB68FACE4586256D35004F60AC/$FILE/D20G5LE0503.pdf

.............................................
Here's SPECIFIC PART & Retail Source

http://www.mouser.com

Omron G5LE-1A4-DC9

9V SPST Normally Open

http://www.mouser.com/search/productdetail.aspx?R=G5LE-1A4-DC9virtualkey65300000virtualkey653-G5LE-1A4-DC9

..................................................
They have a variety available

Example:
12Volt versions in both SPDT & SPST
and 9V in SPDT

Search for " G5LE " at Mouser and it'll show All the versions & specs

..............................
These are all about $1 each,or so.
Shipping is about $5~6

I'd suggest buying 3~4 for a couple of reasons
*Test the item BEFORE soldering to board.
It's possible to get a defective NEW "anything".
*In case of damage or loss while handling/installing
*For any possible Future need

*And Most of all,,"Cheap Insurance"
If ya buy ONE only,,,somehow you'll NEED 2.
But if you buy 2 or more,,,You'll never need the extras in a million years:)

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

The Omron G5LE-1A4-DC9
MIGHT be Identical,Direct Replacement.

The Only difference would be location of it's single terminal pin,,,requiring Jumper Wire to connect it.

Good Luck,hope that helps