Kohler Generator FAQ: Answers from an Office Administrator's Experience

Kohler Generator Questions I’ve Actually Had to Answer

I’ve been the office administrator handling generator purchases for my company since 2020. We run a mix of Kohler units – a couple of 150 kW standbys for the main building, a 900 kVA beast for a data center expansion, and a marine generator on our service boat. Roughly $60k in generator-related spending annually across three vendors. Here are the questions that keep coming up from my colleagues and contractors (honestly, some I had to learn the hard way).

1. What makes Kohler generators worth the premium over other brands?

Basically, reliability and support. In my experience across about 20 generator orders, Kohler’s liquid-cooled models (especially the 900 kVA range) have way fewer field failures than some competitors. That said – I’m not an engineer, so I can’t speak to the technical specs. From a procurement perspective, the dealer network is what sold me. When our 150 kW had a controller glitch last winter, we had a technician on-site within 6 hours (thankfully, because it was -10°F). Not all brands offer that kind of coverage in our region.

2. How often should I replace the impeller on a Kohler marine generator?

I manage our boat’s generator maintenance schedule, but I’m no marine mechanic. The impeller is one of those parts I’d rather leave to the pros. Our service company recommends every 2 years or 500 hours, whichever comes first. But here’s the thing – if you run in sandy or silty water (like we do in the Gulf), the wear accelerates. We had a near-miss last season when the impeller blades started shedding rubber (ugh). Now I stick to a 1-year interval for our Kohler marine generator. Check your owner’s manual, but honestly, err on the shorter side if your waters are dirty.

3. What’s a “fuel filter with return line” and why should I care?

I’ll be straight with you – I had to ask our parts supplier about this one. A fuel filter with a return line (often called a “return-style filter”) allows unused fuel to circulate back to the tank. It’s common on diesel Kohler generators to prevent vapor lock and keep the fuel cool. When I ordered a replacement for our 900 kVA unit, the vendor said “make sure you get the one with the return port” (which, honestly, I’d never heard of before). The cost difference was about $15, but using the wrong filter could cause priming issues. So if you’re buying a fuel filter for your Kohler, double-check whether it needs a return line. Don’t hold me to the exact part number – ask your dealer.

4. How often should I change the air filter if I have pets?

This is more common than you’d think. Our maintenance shed has two office dogs that like to nap near the generator intake. Dog hair and dander clog air filters way faster than normal dust. In our case, we went from 6-month intervals to every 3 months. I discovered this after a surprise (not the good kind): the generator overheated on a test run because the filter was matted with fur. The Kohler tech told me pet hair is basically a filter’s worst enemy. So if your generator lives where animals hang out, plan to inspect the air filter every 60 days. Replace when it looks dirty – for us, that’s about every 2-3 months.

5. Can I unclog a fuel filter myself?

I’d say maybe, but don’t count on it. From my experience, if a fuel filter is clogged, you’re better off replacing it. Unclogging can push debris downstream into the injection system (which is a much pricier repair). In 2022, we tried to save $50 by cleaning a clogged filter on our portable generator. Ended up with injector damage that cost $800 to fix – (surprise, surprise). That said, if you’re in a remote situation and need a temporary fix, you can remove the filter and blow it out with compressed air from the outlet side. But seriously, order a replacement immediately. And always use the correct micron rating for your Kohler model.

6. What’s the biggest mistake when buying a 900 kVA Kohler generator?

Without a doubt, underestimating installation costs. When I sourced our 900 kVA unit, the generator itself was $X (I’m not 100% sure, but roughly $40k-50k based on our bid). But the total project – concrete pad, fuel tank, transfer switch, commissioning – came to over $80k. The vendor who said “we can do it all” turned out to have limited electrical experience. That caused a 3-week delay (ugh). Now I separate the generator purchase from installation and vet each contractor separately. Another lesson: don’t assume a 900 kVA unit fits through a standard roll-up door. It didn’t. We had to remove a wall. So measure twice, buy once.

7. When should I call a professional instead of doing it myself?

Honestly, most of the time. I’ve learned that generators involve high voltage, flammable fuel, and critical safety systems. In my opinion, unless you’re a licensed electrician or certified Kohler technician, limit DIY to things like changing air filters, checking coolant levels, and cleaning the exterior. Everything else – impeller replacement, fuel system work, controller programming – is best left to a pro. We have a service contract with a local Kohler dealer for major maintenance, and it’s saved us from at least two major failures I can think of. The $200 annual inspection fee is cheap insurance compared to a $5,000 repair. Seriously.

(Prices as of Q1 2025; verify current rates with your local dealer. My experience is based on a fleet of 8 generators across 3 locations – your setup may vary.)