Generator Surging & running rough

J

jmunro123

Member
Feb 2, 2008
370
Gran Bend, Great Lakes
Boat Info
2004 Sea Ray 390 Motor Yacht
Engines
8.1's
I was 'exercising' the generator this weekend and noticed it was running rough. First it took a few try’s to get it started. When it did start without a load it alternated between running low rpm and higher (not high) rpm. After about 1 min I turned on the water heater and the revving continued then I turned on one stove element and the generator ran about 1 min then stopped. I turned off the lgenerator breaker and started it again but still revved up and down. Then I turned it off.

The generator did not get used that much last year so this year I thought I would start it once a week just so it has a chance to run.

I think its a 5KW gen from Kroler. The gas is from last year. I was thinking it could be old gas but the main engines run fine. I did a search on clubsearay and it suggest changing the spark plugs. The Gen has about 60hr on it.

What does everyone suggest?
 
Start with plugs....my Kohler 5E has a Kawasaki twin that run NGK's....sorry I don't know the number...next you may want to change your spin on filter / water seperator.
 
The mains may run fine bu the gens are more sensitive and you would be suprised what old gas will do to a performance of a gen. Try dumping some Sea Foam in your tank, clean/replace the fuel filter and follow Stray Cat's advice and check/change the plugs. Kohlers have to have a load or they foul plugs. I have a Westerbeke and mine does the same thing sometimes; hunts! There is a gain control on the control box that needs to be adjusted and this usually corrects the hunting problem. Good luck
 
Stray Cat said:
Start with plugs....my Kohler 5E has a Kawasaki twin that run NGK's....sorry I don't know the number...next you may want to change your spin on filter / water seperator.
Click to expand...

I also bought the higher-end NGK's for mine and they run fine. Lowe's carries them in the lawn mower section. I have a post somewhere with the right model number but if you bring the old plugs you can match them up pretty easily. I think the match numbers are also on the NGK website.
 
yup
sounds like plugs
I would start by replacing them
wouldn't hurt to keep a spare set onboard too.....
Kohlers go through plugs quickly
 
I agree spark plugs. You can't see the rear plug gotta do it by feel. Don't drop it. It's hard to recover.:smt013
 
A few weeks ago as I was getting ready for the summer, my gen was acting very similar to what you are seeing right now. I even had some old gas left in the tanks from last season just like yourself. I started a thread here on CSR and everyone told me the same thing you are seeing, start with the plugs.

Took less than 20 mins to change them out, and its run perfect ever since.
 
Plugs almost certainly......now if all of our mechanical issues were so cheap and easy to rectify! :smt038
 
Preach it brother! If every problem could be fixed for less than $10 for a boat, we would all be a few dollars richer!!
 
Thanks everyone. I am heading to the boat tomorrow and will get the part number from the plugs and get some new ones installed. When I am done I'll try to remember to report back.
 
Are you starting the gen in the engine room or on the panel in the cabin? Start the gen in the engine room and goose the throttle lever and choke lever just after the start up.
 
As stated before, change the plugs and definitely keep an extra set (or 2) on the boat. I changed form the NGK's to Autolite 65's. Much cheaper and easier to get. Dont be affraid to run that gen and make sure you put a load on it when you use it. The Koehler 5e doesnt like to run without a load on it. Also, make sure you lubricate the choke on it. They have a tendency to stick causing rough starting at times.
 
I have the same generator and I'm having a similar problem. Mine surges then dies ... sometimes it won't start at all. I'm going to try changing the gas filters. What about those electronic gas line shutoffs? Anyone ever hear of them failing to open?

BTW - it only has 17 hours on it.

-Charlie
 
charlieft said:
What about those electronic gas line shutoffs? Anyone ever hear of them failing to open?
BTW - it only has 17 hours on it.-Charlie
Click to expand...

Do you mean the solenoid valve? They are pretty easy to trouble shoot....often you can hear them click when they open and close....or you can take a small screw driver or a thin steel rule and hold it about an 1/8 of an inch or so over the top of the coil. Have someone turn the switch on, when the coil is pulling the poppet open inside, a magnetic field is created and you will feel the screwdriver or steel rule being pulled toward the coil.

The solenoids on my boat have a manual overide that can offer fuel flow in the event of a coil failure. When a coil fails, it is done. The poppet will return to the normally closed position and stay there until it is either magnetically pulled or manually overidden.
 
MAKC said:
As stated before, change the plugs and definitely keep an extra set (or 2) on the boat. I changed form the NGK's to Autolite 65's. Much cheaper and easier to get. Dont be affraid to run that gen and make sure you put a load on it when you use it. The Koehler 5e doesnt like to run without a load on it. Also, make sure you lubricate the choke on it. They have a tendency to stick causing rough starting at times.
Click to expand...

Hi Mike,

I see your genny is a Kohler 5E - same as mine. What do you set the gap on the Autolite 65s? And what are you using as a choke linkage lubricant?

Thanks!
 
Just wanted to post a follow up. I changed the plugs on Sunday and the surging problem is gone. We ran it while at anchor and it worked great. Man that is the cheapest repair yet!
 
My question is how do you get to the plug? I have a 2002 340 Dancer. Seems like the plug is against the side of the boat.....:smt100
 
Since we are talking generators
I have a 240 Sundancer that I would like to have a
generator onboard. Do they make one for it and where would it go.

Jim
 
Similar problem here. We have a 7.5 KW Kohler and it runs fine at idle. But, when I load it up to excercise it, it's running really rough. No change in RPM, just sounds like crap. It has about 200 hours over 5 years of use. I'm realizing now that I've been using it too little. Will change that practice from now on. It gets regular oil changes every year, but the plugs and fuel filters have been neglected.

I was going to change the fuel filters and the plug(s) to start. I only noticed one plug, so I'll have to hunt around for the other. Hoping for the same result...

Kevin
 
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