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Kohler 7.3 generator issue

Posted: June 16th, 2020, 10:36 pm
by Helmsman
I had my generator tuned up (spark plug (s)), carb adjustment, antifreeze, impeller, oil, and filter. The main reason I had it in was after starting, it would burn white smoke and labor some for about a minute or so, sometimes longer.

The gennie worked fine afterwards and up until the last two trips. Now, it takes two or three attempts to start it. It will eventually start, but I am concerned as to the possible causes. I would like to know step 1, 2, 3 to check for issues.

Thanks for any help you can give.

Re: Kohler 7.3 generator issue

Posted: June 17th, 2020, 7:50 am
by bud37
One question........is the level of antifreeze in the expansion bottle going down or staying the same ? Check cold regularly before start up, if you are not sure mark the level with a sharpie then monitor.

Re: Kohler 7.3 generator issue

Posted: June 17th, 2020, 9:29 am
by Helmsman
bud37 wrote:Source of the post One question........is the level of antifreeze in the expansion bottle going down or staying the same ? Check cold regularly before start up, if you are not sure mark the level with a sharpie then monitor.


Thanks Bud! I will check the antifreeze level. I am not sure how that would prevent the generator from firing up. Certainly, it could cause it to shut down prematurely.

Re: Kohler 7.3 generator issue

Posted: June 17th, 2020, 10:09 am
by Viper
I think what Bud's suspecting is that you may have coolant leaking into a cylinder, thus the white smoke. Would also contribute to hard starting. By monitoring the coolant level, it'll give you an indication if that's a possible cause. Or pressure test the cooling system.

Re: Kohler 7.3 generator issue

Posted: June 17th, 2020, 11:26 am
by Helmsman
Thanks Viper. The white smoke was no longer an issue after the tune up last fall. The only issue I am having is with starting the generator. I had the work completed in November. The generator started up and ran as it was supposed to on the way back. This spring, after de-winterization, the generator started right up and ran like a top. First few trips out, everything good. Then, the last two trips it took two or three times to start.i was thinking perhaps a fuel issue? Also, I had to drain my engine fuel Water separators on my Port and Sbd engines because the port RPM’s we’re jumping everywhere. Could it be an issue with water in the fuel line?

What I am looking for is the steps to take to look at fixing a hard starting generator.

Re: Kohler 7.3 generator issue

Posted: June 17th, 2020, 11:08 pm
by Viper
Ya could be a number of things but start with the simple things first like fuel filters. I'm not sure of the exact model you have so not sure if there is an onboard filter and whether you have a primary spin-on. When replacing the filters, check the contents for debris and water. Check the condition of the plugs to see if they're fouled. If they are, check your oil level, check it anyway. Overfilling will cause problems. Try running it on a portable fuel tank to eliminate the ship's fuel circuit like the fuel line, anti-siphon valve, etc. Also ensure you have over a quarter tank of fuel.

Does she run fine under full load after you manage to get her started? Have you been using the generator on a regular basis during your ownership?

Re: Kohler 7.3 generator issue

Posted: June 17th, 2020, 11:17 pm
by Helmsman
Viper wrote:Source of the post Ya could be a number of things but start with the simple things first like fuel filters. I'm not sure of the exact model you have so not sure if there is an onboard filter and whether you have a primary spin-on. When replacing the filters, check the contents for debris and water. Check the condition of the plugs to see if they're fouled. If they are, check your oil level, check it anyway. Overfilling will cause problems. Try running it on a portable fuel tank to eliminate the ship's fuel circuit like the fuel line, anti-siphon valve, etc. Also ensure you have over a quarter tank of fuel.

Does she run fine under full load after you manage to get her started? Have you been using the generator on a regular basis during your ownership?


Thanks! We have used it regularly, And it is running fine after start up with a full load. It is a Kohler 7.3e 2006, I think. I will pull the manual tomorrow and get back with you on the exact model.

Re: Kohler 7.3 generator issue

Posted: June 18th, 2020, 7:22 am
by Viper
When you say that it's hard to start and it takes two to three attempts, is it that she turns over really easy but just won't fire up and run, or does she turn over easy, fire/runs then dies, or does she struggle to turn over when you try to start her?

Re: Kohler 7.3 generator issue

Posted: June 18th, 2020, 8:32 am
by km1125
Nharrison5 wrote:Source of the post I had my generator tuned up (spark plug (s)), carb adjustment, antifreeze, impeller, oil, and filter. ...
The gennie worked fine afterwards and up until the last two trips. Now, it takes two or three attempts to start it. It will eventually start, but I am concerned as to the possible causes. I would like to know step 1, 2, 3 to check for issues.
...

Nharrison5 wrote:The only issue I am having is with starting the generator. I had the work completed in November. The generator started up and ran as it was supposed to on the way back. This spring, after de-winterization, the generator started right up and ran like a top. First few trips out, everything good. Then, the last two trips it took two or three times to start.i was thinking perhaps a fuel issue? Also, I had to drain my engine fuel Water separators on my Port and Sbd engines because the port RPM’s we’re jumping everywhere. Could it be an issue with water in the fuel line?

Since the genset pulls from the same fuel source as the engines, it's likely it got the same kind of dose of water that the engines got. It would take a lot longer to work that water-laden gas through the generator, so that would be my first suspect. If you're sure the tanks have good gas in them now (did you find the source of the water in the engine filters?) and you get it started, put a heavy load on it and run it for a while to work all that "old" gas through the system.

Re: Kohler 7.3 generator issue

Posted: June 18th, 2020, 9:42 am
by Helmsman
Viper wrote:Source of the post When you say that it's hard to start and it takes two to three attempts, is it that she turns over really easy but just won't fire up and run, or does she turn over easy, fire/runs then dies, or does she struggle to turn over when you try to start her?


It turns over and you can hear the breaker “trying” to switch over from the shore power breaker. After about 10 or so seconds, I give it a break. The next step is to attempt a re-start about 15 or so seconds after the first attempt. One time it fired up at that attempt. The next two times it took three times to get it to start. I will head down to the boat later today to start from the generator itself so I can hear a little better than in the cabin. I will also check the antifreeze level, the oil level, and the fuel filter if I can find it.