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Kohler Generator on the Fritz

chuckhanson

chuckhanson

Regular Contributor
"This is a second attempt to l

"This is a second attempt to leave this message.

I have a 7.5 KW Kohler generator. It recently got a new carb, fuel pump, magneto, fuel filter/water separator and starter motor. After this it ran good for 30 hours or so. Now I am having problems. Symptoms: runs for 30 minutes then quits like it ran out of gas. Prime the fuel pump with the manual lever and it starts up again and runs for 30 more minutes then quits again. This went on for a while then down to 10 minutes then 5 and now it won't start at all.

Any ideas? I am on the boat for two days and can try some things.

Thanks

Chuck Hanson"
 
"Chuck:

Make it screw up ag

"Chuck:

Make it screw up again and immediately check for spark. If okay, bypass the fuel pump with an outboard tank and force fuel into the carb. If it then runs okay, it's the pump. I've seen new pumps fail, and good pumps not operate correctly do to the cam system operating them.

Have fun!

Jeff"
 
I have confirmed that I have s

I have confirmed that I have spark to the plugs. I changed the fuel filter/seperator and found just a little water. I am in the process of pulling the bowl on the carb to be sure I don't have water there. I also intend to pull the plugs and make sure they are not wet.

I will post results in an hour or two.

Chuck
 
"Chuck,
May seem like a simpl

"Chuck,
May seem like a simple solution, but I've got a 6.5KW Kohler gen set that had the exact same problem. Turned out to be that the genset was low on oil. Once the oil was topped up, the unit continued as normal."
 
"Well I will check it however

"Well I will check it however I just changed the oil a few hours ago. My oil pressure is constant at 20 psi.

I am leaning toward a fuel pump problem. The gen is back to running again. I changed the plugs and cleaned the carb. Now it is running for 10 minutes then stops. I have cleared the three safety shutdowns (low oil pressure, high water temp, and high head temperature.

When it stops I checked the fire at the plugs and it was ok. After it stops I can pump the manual lever on the fuel pump. I can hear gasoline sucking into the filter. When the carb is full the sucking sound stops.

I will put gasoline line directly to the carb tomorrow bypassing the fuel pump. If it runs continuously I will know the fuel pump is bad.

Any ideas.

Chuck"
 
On my Kohler 12.5 I added a a

On my Kohler 12.5 I added a a fuel pressure gauge just after the fuel pump. I was having issues with the stock pump picking up from the tank when the tank was a 1/4 full or less. It always started but would die out a few minutes later. The gauge helped me with priming and identifying pump problems. I ended up replacing the stock fuel pump with a Carter.
 
..."I was having issues wi

..."I was having issues with the stock pump picking up from the tank when the tank was a 1/4 full or less."

Ah hah! Most RVs are set up such that the gen-set DELIBERATELY runs out of gas long before the main engine(s) do. THis is to keep you from dying on the side of the road.

Perhaps this is your problem?

Jeff
 
For me it was on my boat and u

For me it was on my boat and uses the same pickup as the engines. Checking the specs on the factory pump showed it had 24" of lift. Short of what I needed. Also with the anti-siphon in line made it even worse. The carter had a greater lift capacity.
 
"Jeff, thanks for the feed bac

"Jeff, thanks for the feed back. Mine uses the same fuel pickup as the starboard engine. I always start the starboard engine and run it a few minutes before I run the generator so any water will be picked up by its water seperator because it is larger.

My generator is a Kohler Model 7.5R27; Specification 106276A. Any ideas where I can purchase a fuel pump? I like the Carter idea. How would I cross reference it with the Kohler part?

It rained so hard today I couldn't try the direct feed of gasoline to the carb. Will have to wait until next week now."
 
On the first start it ran 1 ho

On the first start it ran 1 hour. I thought it was fixed. When I returned it ran only 10 minutes.

After replacing the coil in the magneto it has run for 3.5 hours. A little over one hour for three runs.

Chuck
 
"Thanks, Jeff. I am going to

"Thanks, Jeff. I am going to China for a couple of weeks so I won't get a chance to give it the real test until I get back.

Chuck Hanson"
 
Chuck:

you can always explo

Chuck:

you can always exploit the opportunities available.....bet you can buy several mag systems over there real cheap.
 
"Chuck, I have several 4 cylin

"Chuck, I have several 4 cylinder 1920's Indian magnetos that still run great if you need, although your genny is probably 3 cyl. They came from Springfield, Mass....not China !"
 
"I thought I would catch you u

"I thought I would catch you up on the continuing saga of my Kohler generator. After I got back from China it was up to its old tricks... run for 10 minutes then shut down. I sent the magneto back to be rebuilt for the 3rd time. The coil was bad.

This is what I found with the help of Standard Magneto in Chicago. About a year and a half ago some mechanic replaced the spark wires on the generator. He installed carbon filled wires. For this magneto a wire filed plug wire must be used or it will cause the magneto to arc internally and burn the coil. There is too much resistance in the carbon filled wires. I measured the resistance in the wires that were installed at 11,000 to 14,000 ohms for 14 inches of wire. There is close to zero resistance in the copper filled wires I used as a replacement.

I ran the generator for 3 hours today and it is working fine. Only time will tell if this is really the problem. If this is the case, I will write a book. The only problem is that I don't think many copies would sell.

My lesson learned is to check behind mechanics after they work on the boat. When I sent it back the first time the technician at Standard Magneto asked me if I had carbon filled wires and I told him no that the wires were original. Today I cut one of the wires into and found they were carbon filled. I should have checked a year ago.

I am happy until the next time.

Chuck Hanson"
 
On the Subject of 7.5 Kohlers

On the Subject of 7.5 Kohlers Mine is running now but I seem to have misplaced the drain plug on the muffler. It seems to be approx. 1/4 " Does anyone know the correct size? Thanks Art
 
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