Lawn and Garden tractor batteries usually come in 4 different ratings - all in the same sized battery case. Ratings are approximate. 180 cold cranking amps 230 cold cranking amps 300 cold cranking amps 340 cold cranking amps Batteries that are vented through removable battery caps are likely to develop corrosion on the battery terminals. The sealed batteries are vented differently and do not develop the corrosion on battery terminals. Sealed batteries are usually higher priced than the batteries with the removable caps. With the larger engines such as your 25 hp Kohler, the 300 or 340 cold cranking amp battery has more capacity and will most likely last longer than the batteries with lower cold cranking amp ratings. If your tractor runs out of fuel, the higher rating battery will crank the engine longer to pick up fuel. The lower rating batteries are more suitable for the single cylinder engines. Concerning the sealed versus non sealed batteries, would you rather have a battery that corrodes or a battery that does not corrodes - but costs an additional $5.00?

I concur with using a sealed battery. I have also had only good experiences with Deka brand by East Penn. When my employer used them in the truck and forklift fleet, corrosion was unknown for the entire time Deka batteries were the standard. Then, company changed management and battery brand. The first of the "new brand" were Exide branded batteries and it was the biggest bad choice I ever saw in selecting a battery. The corrosion problems caused by those (and subsequent brands since) is so bad that whatever $ savings the company managers "imagine" they are getting from using el cheapo batteries is quickly spent (and then some) replacing cables and battery holder components. A typical example of the old "penny wise but pound foolish" adage.

The "engine light" primary purpose is to monitor the emissions control system. Anything that affects emission will trigger this, and the event will be remembered, at least for the newer OBD II system.. So, the thing to do here is to bring all the cars service requirements up to date. This problem could be something as simple as battery terminal corrosion up to some sensor or a relay. Then, have the "codes read".. An interpretation of the codes may help...

I re-read your post. Your starter acts like one whose electrical contacts are worn out. The soleniod may or may not be able to establish the power circuit. If, when you turn the key to the start position, all you hear is the soleniod going "clunk" and nothing else, then the power circuit has not been established. As another check, open the door and watch the dome light as you try to start. You should be able to discern if the power contacts make circuit by watching the degree of dimming of the dome light. If, as I suspect, the power contacts are worn out, I fear this starter will leave you stranded soon. You'll get the truck started and go somewhere only to find it will not start again (until the starter is repaired or replaced). It makes more sense to run this truck into a garage while it still starts and replace the starter before it strands you (and it) somewhere.