We purchased our Carver last fall, with a Kohler 7KW genny, and it ran awful. Well, it would run at idle without load, but once load was applied, such as coffee maker, water heater, or A/C, it would shudder and almost stall. The first run, it had smoky exhaust. It only has 90 hours on it, so it just has not been run enough. All of my Kohler research says that the VERY FIRST thing to check when they run poorly, are the sparkplugs. This I already knew from past experience.
Installing new NGK BPR4ES sparkplugs today - gap them .024 to .028 - as well as a fresh oil filter and refill with 10W30 Mobil 1 oil, and she ran as smooth as butter. Under full load - water heater, coffee maker, A/C pump, battery chargers, everything - she purred like a happy cat.
It's well known that if you want your genny to run well, then run it often, and put her under load. I've been told my a marine expert that the genny should be started each and every weekend, or as often as I go to the boat. That way, there should be few surprises when we leave on a boating holiday or extended trip and really need the genny.
Purchase your own oil vacuum pump from a marine store - about $100.00 - and use it to vacuum out your old oil. (You can use this to change your own engine oil as well)
You can install a new filter - the Kohler 4KW and 7KW take the same size filter, a FRAM PH4967 or a WIX 51394. Buy your own filter wrench and keep it onboard. Buy a couple of extra filters, and keep on board.
The NGK BPR4ES plug are available at the PartSource auto supply stores. Ask for NGK stock #7222, which is a pack of four. Install two, and keep two on board for spares, along with a sparkplug socket. If your genny acts up when you are miles from home, or at a beautiful anchorage, you don't need to call for a mechanic or head for a marina.
Make your genny happy. I'm sure you have already heard this one: "Happy genny, happy life."
What about impellers? We can cover that in another post. Just keep an eye on your genny exhaust and make sure she is throwing out lots of water. If no water, shut the genny down fast. You should carry a spare impeller on board also.
Happy boating everyone!
Steve


