Generator has electric start. When I turn key to start position I only get one click. Battery is new. Not sure what to check next

it seems like your ignition switch may not be removing the ground while in the starting position try removing the ground wire from key switch if it turns over and start with key replace switch assy.

We are Perkins diesel generator OEM and can provide 22KW to 1800KW Perkins diesel generator including open type,silent type and container type genset. Each genset has its user's manual.

Normal starting procedure of Perkins Generator set

1. As far as possible do not start the generator set under load conditions.

2. Transfer the key switch to the starting (STAR) position. The engine should start immediately.

3. After the engine starts, return the key switch to the running (RUN) position. If the engine has not started after 10 seconds, turn the key switch back into operation and (RUN) for 10 seconds. Then repeat steps 2 and 3. If the engine is still unable to start after three attempts, please find out why.

4. After engine starts, follow steps 4.a and 4.b.

A. Check the oil pressure.
B. Check the machine for leaks.
C. Make sure the battery is charged.
D. After running the engine for five minutes, check the generator monitoring system. Make sure the engine works properly before loading.

Note: do not use ether-like spray starting aids in cold weather. Otherwise, it could lead to explosion and personal injury.

The use of water jacket heaters or extra battery capacity improves the machine's start-ability below 10 ?.

Methods for checking and cleaning the core of the rear cooler of Perkins generator set

Check for damage, corrosion, dirt, grease, insect stains, leaves, oil and other debris on the cooler. Clean the cooler if necessary.

https://www.dieselgeneratortech.com/generator-sets/Instruction-for-Perkins-Generator-Set-Maintenance.html

If you can turn the key, the problem is electrical. If you can't turn the key,is ignition look cylinder.buy new cylinder with the key. disconnect the battery,turn the cylinder to run position and push the look pin on the cylinder with small punch and pull. insert the new one and you are ready to go.
If the cylinder turn and don't start,is electrical.
with one hand turn and hold the key to starting position with other hand shift slowly from PARK to NEUTRAL. I the engine start ,adjust the neutral safety switch
For next you need helper.
one person start with the key and other with test light check if power go to the starter solenoid. if power go to the small wore, replace the starter

check with volt meter. 12 volts with engine off. Should be 14 volts with engine running if alternator is working.
First, clean battery posts and cable ends. Then check owner manual for fuse locations and blown fuses. There is a large 100 amp fuse in box under hood.

Is the battery lamp lit on the dash?

Looks like 3 bolts. please rate when done

SECTION 414-02: Generator and Regulator 1998 Escort/Tracer Workshop Manual
REMOVAL AND INSTALLATION Generator -Sedan and Wagon Removal

1. Disconnect the battery ground cable.

1. Remove the generator drive belt.
   1. Release the tension on the drive belt.
   1. Remove the drive belt from the generator pulley.

1. Disconnect the HO2 sensor harness clip from the generator bracket.

1. Position the generator bracket aside.
   1. Remove the A/C line bracket bolt.
   1. Remove the power steering pressure line bracket bolts.
   1. Remove the generator bracket bolts.
   1. Position the generator bracket aside.

1. Remove the generator bolts and position the generator aside.

1. Remove the generator.
   1. Disconnect the two generator electrical connectors.
   1. Remove the battery positive nut and washer.
   1. Disconnect the battery positive cable and remove the generator.

step 4

It may have a seperate starter button

IF IT IS A HONDA ,KEN . JUST UN PLUG THE LOW OIL CUTOUT SWITCH JUST TO BE ON THE SAFE SIDE MANY OF THEM GIVE TROUBLE.
IS IT TURNING OVER AND JUST NOT STARTING,OR DOES IT REFUSE TO CRANK? IF THAT IS THE CASE CHECKTHAT YOU HAVE A GOOD EARTH CONTACT.LET ME KNOW WHAT MODEL THE MOTOR IS "YOUDOIT"

First, remove the battery terminals and clean them. Check that the ground wire on the block is tight and clean and the wire at the starter is also good. If you have 12v at the main starter cable and12v at the smaller (trigger) wire next to it with the key turned to the "start" position, it's likely the starter is bad (providing you can turn the engine by hand with key switch off) Make sure that the battery has 12v before starting diagnosis...radio etc. draw far less than the starter does. Even if relatively new, if the charging system isn't working, it will draw down the battery in less than an hour while driving..

This could be a number of things. If the battery is good, open your fuse box, and check all the fuses to make sure none are blown.. Next you have to check if your starter ground is good. It sounds like if it's not a fuse, you need to put a new starter in.

If the engine will not crank-if it has an electric start, first check the battery and connections to the starter and ground. If the battery is good and the connections are clean and tight, then I would check the ignition switch. If it clicks once when the key is turned to the start position, check for a seized crankshaft (see below) If it does not click, then it could be the starter, solenoid, or the ignition switch. If it has a manual pull start, and it will not pull, check to make sure the crankshaft can turn freely and if not, disconnect the pull starter and check it again-if it turns freely the rope start mechanism is hung up-it must be freed up before you can pull start it. If the crankshaft will not turn at all you probably have a serious problem that will require a major teardown.

I have seen this happen in cars- the problem is most likel the ignition unit -they do not spend a lot of money on them in production. So here is what is happening . When you are putting key in and out metal filings are being deposited inside unit- this is now causing a short and draining batteries. Start here.This happened with cars a few years ago and they were catching fire in driveways.Call dealer and get replacement ignition- should be cheap fix. Good luck.