Ultima ZT1 Hard to Start

[btnewton1208]

New to this site! I have a 42" Ultima ZT1 that I believe is about 6 years old. I'm looking for some help because I have trouble when it comes to starting it. I can turn the key and it tries to start, but not luck to get it going. If I pour a little gas into the air filter hole, it will fire right up, and continue to run as long as I need it to. However, the moment I shut it off, it will not start again without me putting a little gas through the air filter hole. Recently replaced starter, starter solenoid, and ignition switch. Carb and fuel pump replaced about 10-12 months ago. Spark plugs were replaced in 08/23 This weekend I am going to do an oil change, spark plug change, and make sure carb is clean.

Is there something I may be missing that could be the issue here?

I am not the most mechanically inclined person, but I can work on stuff. Please forgive me if I don't use proper terminology!

[Billy-O]

No mention of the choke... is it functioning properly?

Should not have to use choke to start after engine is shut down. You mention you need to drop a little down the hatch even after you shut down. Was engine still warm?

All the stuff you did, no mention of checking fuel flow and fuel filter.

My father has a Bad Boy ZT with Kawasaki motor and claims he has less starting issues with using STA-BIL. Not sure if that's true, but doesn't hurt to try, especially with fuel sitting around a while.

[btnewton1208]

When I start the mower, I try to start it with the throttle all the way up which is choking it. Even if I try to start it in a lower setting, it does the same. For example, when cold starting it, I put the throttle all the way and try cranking it. No luck regardless of where I move the throttle. Once it gets going, I ran it for a good 10-15 minutes mowing with no issues at all. If I stop and try restarting(with warm engine and throttle in mid position) it just tries to crank over and over. The minute I put a little gas into air hatch, it fires right up and does fine.

I think the fuel filter is not that old, but we are in a VERY dusty area. I was going to change that with the other stuff when I buy the whole maintenance kit, and I figured I could blow out the fuel lines as well.

I did buy some STA-BIL to put in already just hoping it may be something that can help, however I havent had the chance to put it in.

Just didn't know if I was on the right track with everything, or if maybe there is something else I am missing that may be a bigger issue(or even a smaller one I am overlooking).

[Ol’ Autocrosser]

My ZT1 is about 2023 model, a 50” with the 23 hp Kawasaki FR691V engine, and mine has a MANUAL choke. Are you SURE you have an automatic or throttle-controlled choke (entirely possible you do since yours is a little older and a possible different engine variant)? The attached photo shows my panel, and the choke lever is the round knob at the very right side of the photo, just to the right of the throttle lever (it’s NOT clearly labeled).

Mine starts instantly, every time, using the following procedure:
1) Throttle CLOSED;
2) Manual choke ON (pulled up) about half way or more;
3) Twist the key with my left hand while my right hand is on the choke knob
4) The instant the engine fires, I press the choke knob back down fully (so the choke is off).

I live in Kansas, so my summers may be shorter, but are just as hot.

I do this 100% of the time - engine hot or cold, I have tried hot starts without the choke, and it will occasionally start that way, but it works so much better using the above method, it’s not worth it for me to try starting without the choke.

In any case, over the years I have found that different engines have their own personalities, and very often will respond to starting techniques different from what is laid out in the owners manual. Basically, if you find a different way that works, use it.

If you DO have a throttle-controlled choke (if moving the throttle is supposed to close the choke as you described), the throttle cable or linkage may simply be out of adjustment. You can verify the choke is closing by taking the top off the air cleaner and observe whether the choke butterfly is actually closing completely when you shove the throttle all the way forward. If it’s not, it may be a simple adjustment to solve your problem.

They’re great mowers, so I hope this is of some help!