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Discussion Starter #1
Hello,
I am new to the forum and joined this as a place to hopefuly get some advice and info on garden machinery and small engines.
I have a Craftsman DGT6000 ( about 140 hours) which I wanted to know the correct operating RPM range for and especially what to set RPM at with the 52" mower engaged.
From my research & downloading an engine manual from Kohler it appears that the 27 Kohler is itentended to run between 1200 idle, to not ever exceed 3750 max, max torque available at about 2800.
Most recomendations for various equipment fal within 3200 to 3600 range and I just like to get the correct factory figure for this particular machine or at least know what is correct so I am operating it within range so it lasts rather than overspeeding it.
I did a head gasket replacement myself after sears failed to show 3 times, and I have set it using the dash tac but it has seemed a bit slow since then.
The dash tac shows it in the green high upon starting ( about 3000) at full throttle but just at the start of the green with mower engaged ( about 2600 I think) so I think it needs to go up a bit.
I have a new tiny tac to set it exactly and corectly but cannot obtain the spec info anywhere.
I asked Sears via several methods and they all neglected to give me the info for "liability reasons" and said the only alternative was to use home service to have it set. Ridiculous !

I would appreciate any info about confirming the RPM, no load safe range, full load set and in general what is good or not good for this engine on this machine.

Thanks Much in advance for any input.
 

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I have the idle set at about 1200 using the dash tach. The full throttle position is in the middle of the green area of the tach without the mower deck running. I have the same exact tractor with 92 hrs. What happened that you needed to replace a head gasket? Did you change one or both?
 

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Discussion Starter #3
I did both heads and would recommended that if the time comes, unless hopefully your lucky, and the retrofit was done already at the factory or other place.
The Kohler backfire & then smoking problem was identified on many info sites throughout the web.
At about 100 hrs. and just days out of the extended 2 year warranty which was included free as promotional, I had the engine backfiring on shut off problem, and then later the smoking problem where the engine smokes just after starting that happens per reports between about 50 to 150 hrs. and called Sears.
The smoke is white (oil) and it appears like you were running an insect fogger.
This problem was actually a Kohler problem and many private dealers of all various brands of yard eqiuipment were sent retrofit kits for in stock tractors on the floor to rectify the problem before they were sold.
The repair is actually a kit (or two kits) from Kohler which includes a new gasket and all new design head bolts to prevent the failure happening again if you just replaced only the gaskets.
The new bolts have the same top diameter for about 3/4" under the head and same threads at the bottom end, but are necked down some in between to a smaller diameter which from my web research on this Kohler problem prevents them from heating and expanding as much, which would effectivly be like loosening the bolts, which would allow the gaskets to fail again.
I won't go into the long story of nonsense with 3 last minute cancelled repair appointments by Sears after my taking those days off from work, which happend with sears to try and get this repaired, but in the end I told them to forget it and repaired it mysefly using the parts kits they had shipped to the house at n/c already after the 1 initial visit.
I love this tractor and it seems great, but I will not now buy anything from Sears that isn't small enough so I can carry it back into the store to demand a refund. They initial tech told me if it was not days out of the service agreement they would have usually just replaced the whole engine as it was hard to find enough service time to do this reapair which requires a lot of disassembly. In the past I have witnessed them give people a whole new machine for the trouble I went through. From my whole families experience, their home service proceedure is more than terrible and letters to ther main corporate headquarters customer service VP, brought no relief in the whole situation to get this fixed on an agreed day. Just a final gift certificate $50 for my iconvinience and indication that I needed to let their repair process take its course.
From my experience it is no longer Satisfaction Guaranteed, it is we will do as we wish & tire you out with our process until you give up.

Sorry to vent as well, but hopefully this will answer your question as well as letting others know the specifics about Sears.

Another idea I have heard about which goes against my nature, is to always shut off these engines while at or near hight speed, rather than idle them down first, which prevents any possible backfiring and possible additional stress on the gaskets when really hot.
Seems to work so just to be safe I do it even now.

The upside to this is you do have a really great machine for the price and features, whether you bought yours new or used.

Good luck with yours.
 

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Another idea I have heard about which goes against my nature, is to always shut off these engines while at or near hight speed, rather than idle them down first, which prevents any possible backfiring and possible additional stress on the gaskets when really hot.
Seems to work so just to be safe I do it even now.
That is different, most of the time kohler said idle down and wait 30 sec or so to prevent backfire.
 

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I have always idleed down, run a few minutes and then shut it off. Never had a problem with backfireing.
 

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Discussion Starter #7
Thanks for all the input.
I do shut the tractor off a bit down from high or between low and high as per the manual so I should be alright.
Could set RPM by the dash tac to middle of green but I would still like to know the specs just to have them on record.
It probably does need to go up a bit as mine is just below or at the green area.
Guess I'll have to find someone who works in Sears Service that has access to info, or a friend of a tech.

Again, thanks to all of you that kindly responded.
 

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I have same tractor also. Do not know what rpm's it ran with old engine, it was blown when I bought it. My new engine is the same as old except I now have a 25 amp alternator. New engine runs in same area as you guys have said which does seem a little slow to me also. The first picture is a page out of tractor manual. The alternator gets it rating at 3600 rpm's. Second picture is page from transmission website. I have the -3500 tranny. I think it should say 1800 rpm minimum instead of maximum. The repair manual from Hydro-Gear says 1800 minimum. Third picture is from Kohler factory engine manual telling how to adjust rpm's. If you click on pictures they open up bigger. This might give you a better idea.
 

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i have a 2003 dgt6000 with the 27 hp kohler. it just turned 100 hrs. at the end of last summer it finally quit smoking on startup. also i shut it down while it is running at full throttle 3600 r p m . no back fire . a few times i shut it off at idle. mistake !
 

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I also have a DGT6000. If I don't allow it run at idle for a minute or two before shutting it down, it will backfire and shear the key 5 out of 10 times. I didn't know you were suppose to shut it down at near full throutle.

Thanks, I'll try it.
Paul
 

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I have the same machine, and, contrary to normal procedure, the manual says to set the throttle to between half and full throttle on shutdown as searsman6000 has said. Look on the bottom of the last page (33) of the manual in the troubleshooting section. It's the last item.

I shut the engine on my machine off not by setting the throttle at half to full throttle, but by letting it idle down, then pushing the throttle full forward as I turn the key off. I've never run across an engine that required such high throttle setting for shut off and it kind of goes against my grain. I don't know why it does that, must be something to do with the high performance intake system and getting so much horsepower out of such a small engine. Maybe it has something to do with the compression.

When I was a kid driving our old Ford Model N down the road we would make it backfire by pushing in the clutch, turning the key off, then putting the throttle all the way down, turning the key back on and popping the clutch to restart it. It would backfire every time!

The repair kit you speak of is probably only to repair the damage from the backfiring but not to fix the backfiring problem.

My engine idles at about 2000 rpms and on full throttle runs at about 3500. The engine doesn't seem to be running that hard but I've hardly ever had it not be able to pull through any load. Even when pushing dirt with the dozer blade, it just hums along.

I believe that the exact rpms are not really needed, an approximate setting is more than sufficient unless the engine is constantly overloading and bogging down.

Runningbare
 
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