Crank time for L3710 HST

[Kubota3710]

I recently bought a house and with the house came a L3710 (750 hours) and G1800 (350 hours) to mow the 7 acres of grass.

The glow plug light on the dash of the L3710 was not coming on at all, even with the temperation down below 45 degrees. The tractor would start every time after 5 to 7 seconds, just no glow plug light when the key is turned on.

I did part of the trouble shooting and found the glow plug relay bad, so I replaced it.

Now the light will come on for 1 to 2 seconds when its cold and then go out, but the tractor still takes 5 to 7 seconds to crank.

What is the normal time for the L3710 engine to start after key on. The G1800 starts immediately, and my past experience on a M4900 was immediate starting also when the glow plug conditions were met.

I'm curious what other L3710 owners experience for start times.

Thanks, Rich

 

[SimS]

Rich;

I have a L3710 DT. I live in Georgia so the weather doesn't get too cold. Anyway the glow plug light comes on for 1 - 2 seconds and when I crank it, the engine starts instantly, urrr, urrr, vroooom. It has always started this way and it doesn't seem to be temperature related. BTW the tractor is in an unheated, attached garage. Given that your start times didn't improve after you replaced the relay, maybe you have one or more glow plugs on the fritz. Dunno. Maybe some other folks will chime in with their experience(s).

SimS

 

[GaryE]

Rich,


My 3710 will heat the plugs for about 7 – 10 seconds when cold. It will crank no more than 2 – 3 seconds before it fires. Even when the ambient temperature is well below zero.


You may want to check the condition of your battery. In the summer, my 3710 will fire off almost instantly without waiting for the glowplugs at all.


Also check your glow plug controller. Even when it is relatively warm (below 45 or so) my 3710 will glow the plugs longer 1 – 2 seconds.


Gary

 

[Kubota3710]

Ok, thanks, I had a feeling 5 to 7 seconds of crank time wasn't right. I'm in northern Alabama and tractor is inside an unheated garage.

I'll get the manual and tester out this weekend and test glow plugs and the controller.

I'll let you know what I find.

Thanks again, Rich

 

[simonmeridew]

Rich
first off I didn't know there was such a thing as an unheated garage in
Alabama. I thought it was warm everywhere you went.
Anyway, My L4400 has a 2 direction key switch: turning the key left(ccw)activates the glow plugs, for as long as you hold the key in this direction. Then you turn the key to the right(cw) and start it. Cranks never more than a second and often less from a cold start. Glow plug activation only needed below maybe 45 degrees though. Doesn't matter, starts the same 10 below too. Tractor sits outside all the time. I'd get yours checked if it cranks that long.
How does it start after it warms up?
simonmeridew

 

[Kubota3710]

Two good points. I grew up in Michigan so I guess from that perspective I do have a heated garage here in Alabama. Second, if I turn it off and start it in the next minute or two, it still takes 5 to 7 seconds to crank. Even though it runs fine after start, it will drive me buggy that it isn't working like its supposed to. I hope to be able to troubleshoot it this weekend and find the problem. I'll walk through the manual steps and clean all the electrical connections.

Rich

 

[GaryE]

Rich,


If you are cranking your 3710 5 – 7 seconds when warm, your problem is NOT glow plug related. Diesel's are dependent on cranking speed to start. A weak battery or starter can cause long cranking times. That would be the first place I would be checking.


Good luck,


Gary

 

[RichNJKubota]

As mentioned, check the glow plug controller. It's a box that looks like a relay under the dash. I've heard on this website of these being a problem for a few owners.
Rich
=

 

[Kubota3710]

Ok,

After long hours of troubleshooting and checking wires/switches/etc everything looks ok, except there is not check for the controller. I agree I'm picking up a new glow plug controller tomorrow.

thanks, Rich

 

[Kubota3710]

A New Glow Plug Controller fixed the problem. Crank time is better (2-3 seconds) the battery voltage is only around 11-12 V and drops some when lights are turned on, so I will change it out also. I couldn't measure specific gravity, but voltage seems lower than one would expect. Believe it is the original battery that came with the tractor, so probably 5 to 6 years old.

Thanks for advice.

Rich