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Imow4u2
06-16-2007, 05:18 PM
Just over 400 hrs. on my E.F.I. and around 30 hrs. on service it we be down to the add mark.. Any ideas, this just showed up in the last 150 or so hrs.

tacoma200
06-16-2007, 05:27 PM
Just over 400 hrs. on my E.F.I. and around 30 hrs. on service it we be down to the add mark.. Any ideas, this just showed up in the last 150 or so hrs.

I forget how much oil it takes to fill it from the add mark. That will give us an idea how much it is using in a 30 hr period.

Mark
06-16-2007, 08:48 PM
:usflag: Your engine should not be burning any oil with so little hrs, Ive got a 28 with 2200hrs and it don't use enough to where i can see it on the stick...Should be under warranty...Id let the dealer take a look at it......Do you see any smoke or oil speckles,and maybe the filter is leaking very slowly, but you should see that and oily lines...Something is wrong ........Marks Mowing Service

Richard Martin
06-16-2007, 08:56 PM
How many RPM you turning? My 28 EFI becomes a pig for oil much above 3700.

puppypaws
06-16-2007, 10:46 PM
How many RPM you turning? My 28 EFI becomes a pig for oil much above 3700.

Why would you think only 100 more rpm's would make that much difference in oil consumption?

Richard Martin
06-17-2007, 03:53 AM
Why would you think only 100 more rpm's would make that much difference in oil consumption?

I'm not entirely sure. It could be cylinder pressure or vacuum. My Kohler 25 used to use a lot of oil and it popped head gaskets about every 400 hours when I had it set to 3750 with the blades on. I even put a new head on it to no avail. Once I slowed the RPM down about 100/150 the problem went away. When I bought my 28 EFI it was set to 3800 no load and 3750 with blades on. Right away at 29 hours it was already using oil so I dropped the RPM to 3650 with the blades on and I haven't had to add oil even at a 50 hour OCI.

puppypaws
06-17-2007, 07:07 AM
I'm not entirely sure. It could be cylinder pressure or vacuum. My Kohler 25 used to use a lot of oil and it popped head gaskets about every 400 hours when I had it set to 3750 with the blades on. I even put a new head on it to no avail. Once I slowed the RPM down about 100/150 the problem went away. When I bought my 28 EFI it was set to 3800 no load and 3750 with blades on. Right away at 29 hours it was already using oil so I dropped the RPM to 3650 with the blades on and I haven't had to add oil even at a 50 hour OCI.

I sure appreciate you talking with me about this. I checked the rpm's on mine when it was delivered and it was at 3600 no load, when I checked it a couple of weeks ago it was at 3550 at 225 hrs. I called a Kohler design engineer I kinda became friends with over time and asked him what rpm's could be run on the 28 efi without problems. He said the engine is set up for 3750 on the top end at no load. I said, ok what you are telling me is I can set mine at 3750 no load and will not have to worry about any problems, he said, that is correct.

Now the real life experience you are having is telling a completely different story, it seems to hurt the engine at their recommended rpm setting.

He told me Exmark had factory set their mowers with the 28 efi at 3750, is this true, I really don't know.

I wonder if we would get any input from other owners on this subject if it was in a new thread?

I ran the fool out of mine yesterday and the oil was good when I started. I will see if there is any difference when I check it today. I have only put about 15 hrs. on the mower since I jacked the rpm's up so it may not be ready to show up yet.

Richard Martin
06-17-2007, 08:01 AM
Some people have problems at high RPM settings and some don't. I can't explain it and quite frankly, don't care since there's nothing I can do about it. I lower my RPM and it doesn't use oil, I raise RPM and it blows head gaskets and uses oil.

It's just like that thread about what RPM to shut an engine off at. When I shut my engines off at high RPM I get a big cloud of oil smoke when I start them up again. If I let them sit and idle for a minute or two I don't get a cloud of smoke. I can also hear internal parts ticking as they contract from the heat (from cooling off) if I let them sit and idle. I'm going to pick up one of those infrared thermometers and see exactly what is going on. I know the engineers say they cool better at high RPM but those are the same kind of people who designed the first 2 space shuttles that blew up. Design and actual function may be different, you know what I mean?

Richard Martin
06-17-2007, 08:09 AM
See, now you've made me think about this...

It may simply be a solution as simple as a better head gasket. Kohler uses a graphite based head gasket and it simply may not be up to the job at high RPM. They use a graphite gasket since they are more forgiving on precise torque values and don't require retorqueing or a perfectly flat surface to seal. A better metal based gasket would probably cure the problem.

puppypaws
06-17-2007, 09:27 AM
Some people have problems at high RPM settings and some don't. I can't explain it and quite frankly, don't care since there's nothing I can do about it. I lower my RPM and it doesn't use oil, I raise RPM and it blows head gaskets and uses oil.

It's just like that thread about what RPM to shut an engine off at. When I shut my engines off at high RPM I get a big cloud of oil smoke when I start them up again. If I let them sit and idle for a minute or two I don't get a cloud of smoke. I can also hear internal parts ticking as they contract from the heat (from cooling off) if I let them sit and idle. I'm going to pick up one of those infrared thermometers and see exactly what is going on. I know the engineers say they cool better at high RPM but those are the same kind of people who designed the first 2 space shuttles that blew up. Design and actual function may be different, you know what I mean?

I sure am glad you got on this subject, I checked my oil this morning after running hard yesterday and it is almost down to the add mark. I have never seen the oil go down in this engine enough to hardly notice and by raising the rpm's 150 or so the oil consumption went up tremendously. I had not run the mower as hard continuously as I did yesterday and it sucked up some oil.

What rpm was the maximum you found at no load the oil consumption stopped? I will talk with the Kohler engineer about this but what you said about the space shuttle is true.

Imow4u2
06-17-2007, 09:32 AM
I forget how much oil it takes to fill it from the add mark. That will give us an idea how much it is using in a 30 hr period.

I checked it yesterday and it was very close to add... I'm sure I will have to refill on mon. I'll keep track of what I put in, it can't be more than a pint or so..

I'm turning between 3750-3800 before I made this adjustment this was not a very productive machine.. Seems than just a little hill or rise had it on it's knees even in moderate conditions.. Which I could get the E.F.I. on a Reg. Z with the cooler, That would be a monster in the hills..

razor1
06-17-2007, 10:41 AM
Interesting thread. I've been running Kubota diesels for the last couple of years and got spoiled only having to check the oil about once every 2 to 4 weeks. Now I'm running all Kohler again and I definitely check the oil everyday. They only hold approx. 2 quarts anyway. Years ago I had a 25 hp Kohler get low on oil and it cracked one of the main bearings. :cry:
Anyone use synthetics?

Richard Martin
06-17-2007, 01:39 PM
What rpm was the maximum you found at no load the oil consumption stopped?

It's not really the no load speed that matters since you don't spend much time running around under those conditions. It's the loaded RPM that the engine sees mostly. I did have mine set at about 3575/3600 loaded but I recently increased it to 3650 with no increase in oil consumption. I'd be very hesitant to increase it much further since the next thing that happens after an increase in oil consumption is it blows a head gasket.

puppypaws
06-17-2007, 02:58 PM
It's not really the no load speed that matters since you don't spend much time running around under those conditions. It's the loaded RPM that the engine sees mostly. I did have mine set at about 3575/3600 loaded but I recently increased it to 3650 with no increase in oil consumption. I'd be very hesitant to increase it much further since the next thing that happens after an increase in oil consumption is it blows a head gasket.

3700 at no load should be about right then. I am going to play with mine but I can see without a doubt your oil consumption will go up at Kohler's specified rpm setting. I will talk with them tomorrow.

Imow4u2
06-17-2007, 04:15 PM
Any one Else notice a better/ cleaner cut at increased r's??

I assume that the rated blade tip speed of 18,750 is at 3500-3525 as it seems sitting still with blades engaged eats 75-100 r's..

All I'm trying to accomplish with the xtra tach is to stay in that range while turning the big pumps and cutting some growth...

P.S. better hope P.J. does'nt chime in, as it's rumored that the pumps are set to operate at 3600 r's

corey1977
06-17-2007, 04:18 PM
I use walkers with kohler when it is at the add on the stick hafe a quart will fill the engine