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-   -   Diesel turns over slow, then fast ? (https://www.onlycubcadets.net/forum/showthread.php?t=36434)

ken6x6 01-01-2015 03:05 PM

i play the video to a friend who has built engines and he says it might be a fuel problem. fuel may not be getting to the cylinders at first while it turns over fast then (no smoke from the exhaust) when the fuel does get to the cylinders the compression slows the starter. (smoke starts to appear) then as the fuel starts to burn the rpms increase and it starts. it makes sense, but im not sure im sold on the idea.

dvogtvpe 01-01-2015 07:43 PM

so under that theory it would just turn over slow from the state of cranking if the fuel system where corrected? so I still see a problem there. why don't you start getting some of the things that have been suggested tested and start to narrow it down from there.

J-Mech 01-01-2015 10:10 PM

Fuel is going into it shortly after you start cranking. Just takes it a couple revolutions to show up in the exhaust.

I'm with Don. Start checking over the other stuff. Do the test, then report back.

Not everyone who has "built a few motors" knows what they are doing. You should see some of the stuff I've worked on from guys who were supposed to be "in the know".

PGHsteelworker 01-02-2015 03:11 PM

This may or may not help but on my 1782 I found it started much faster by setting the throttle half way, then heating for 1 cycle. As soon as it fired up I immediately moved the throttle to idle and haven't had any problems doing it this way. Mine doesn't like to start cold at min throttle. Your problem sounds like a intermittent high resistance problem in the starter or solenoid.

ken6x6 01-02-2015 05:04 PM

today i tried some of the mentioned spots to check and techniques for cold starts. i ran the glow plugs for two cycles. although the glow plug light only came on for the first cycle. ?? then i put the throttle to full. cranked it over till i saw smoke, then dropped the throttle to half (while still cranking) and it fired up. the starter didn't drop rpm this time. so i let it run for 30 seconds, shut it down in tried a restart. two cranks of the starter and it fired. i went ahead and pulled the wires off everything starting related. looked for anything abnormal. all was fine. i load tested both battery's. both good. i used the load tester wile running the starter, the volts never dropped below 11. everything seemed to check out.

J-Mech 01-02-2015 05:11 PM

Quote:

Originally Posted by ken6x6 (Post 303169)
i used the load tester wile running the starter, the volts never dropped below 11. everything seemed to check out.

Did it ever do the slow crank during this test?

Sounds like you did a thorough check of the machine. Perhaps even fixing the problem before the tests. If it does it again, put the load tester on and see what the voltage does. I still think the starter is the culprit. But it could have been a poor connection too. :beerchug:

ken6x6 01-03-2015 09:10 AM

j

i never got a slow crank during any of the testing. ill have to agree with you on the starter too. being that's its an intermittent problem, the starter is the only thing i can think of that would do that. ill keep the load tester on it for the next couple cold starts and see if i get any slow cranks with it hooked up.

ol cubber 02-02-2015 11:13 PM

My 882 will crank fast if the oil is very warm... I have found the fast cranking will give it a better chance to start. I have never had luck on starting cold in the winter months. I also had a advantage as I having a deep cell battery to mounted off the back hitch side..... which also more weight for traction.
I went out about a hour ago @ 0 degrees after a hour on the heater with throttle half way up and the third crank it fired right up (new injectors). I think each individual may be misdiagnose some times..... by its individual characteristics and temperament. The Kubota components are very good and have good longevity on the wear. Just my personal thoughts here..... I like hearing other points of view as well.


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