B7800 Won't start

[Alan_Black]

B7800 Won\'t start

Well.... either I'm doing something stupid or I'm getting off to a bad start with this tractor. I had a new B7800 delivered on Tuesday to replace by '48 8N and it's been working fine until today. It fired up this morning, I used it for about 30-45 mins, then shut it off for about 10 mins while I did something else. When I went to fire it back up, it would turn over beautifully but won't fire. I read the post here about bleeding the fuel line and I'm wondering if that is possible since I haven't touched the fuel line (only has 10 hours on it). Anyway, I thought what the heck and went back out there, loosened a bolt/plug on the side of what I think was the injector pump, fuel came out, tried to start it and it fired back up. Used it for about 15 mins again, figured I'd shut it off again and see what happened. Well.... Once again, it won't fire. Tried the same plug and no dice there. Anyone have any ideas? I'm going to call the dealer on Monday to see what's going on (unless I am doing something stupid), but in the meantime, I'd love to get the tractor out of the field and back in the garage.

This brings up a 2nd point. I've never had a diesel before, so are there any "common knowledge" items that I need to know? This seems like it should be a no brainer since a diesel is basically fuel and compression, but I'm at a loss on this one.

I should add that when I first tried to fire it up each of these times it fired for about 1-2 seconds then died out which leads me to fuel starvation???

Thanks guys....

Alan

 

[don716]

Re: B7800 Won\'t start

Do you wait until the glow plug light comes on for a few seconds and then turn the engine over or just start turnning it over?I own a B7500 and was told to wait about 2 seconds after the light comes on and then start the engine. I've done it once without waiting and it did just what the dealer said it would do which is ( Not start). This may be the problem.It's my guess anyway.
Donny

 

[frank_f15]

Re: B7800 Won\'t start

i have to agree with u , sounds like it is only getting enough fuel to run for a few sec. i know u said u worked with it for 30 min or so , but are u sure there is enough fuel in the tank? other than that i can not say. the fuel valve must be open or u would have not been able to work it that long. another outside chance might be that something has plugged off the fuel filter, after it sets it gets enough dielse to fire then starves.

 

[Alan_Black]

Re: B7800 Won\'t start

I've tried both as far as the glow plugs go and it hasn't made a difference. As far as the amount of fuel reaching the engine, what really has me confused is the fact that the 1st time it did it, once I got it started, it ran fine until I shut it down again. I just don't get it.

On a side note, I can hear the starter starting to get a little sluggish, so I may need to jump it to get it going further. This is going to sound really stupid ( The manual is on order since the dealer lost the original, so I can't RTFM yet) but can you jump this like anything else? + to +, - to - standard 12volt system or is there a trick I need to know?

Thanks again guys....

Alan

 

[B2400]

Re: B7800 Won\'t start

When you crank the engine over to start it, do you see any smoke from the exhaust pipe( bluish white)? If so, then you are getting fuel to the engine. If not, then you may have either air in the system or possibly a fuel selenoid problem.

 

[theboman]

Re: B7800 Won\'t start

Check your PTO... Push in the clutch... Push IN the kill switch...Check all the safety features.

It sounds like that's what's going on.

 

[Alan_Black]

Re: B7800 Won\'t start

This is going to sound real stupid, but like I said, the dealer hasn't given me the manual yet. Firstly, I know when the clutch isn;t in or it isn't in Neutral, the starter won't even turn. Will some of the safeties allow it to turn over but not fire? Also, Where is the "kill switch" you're talking about? They didn't mention one when the tractor was delivered and I haven't seen anything that looks obviously like one.

Thanks....

 

[Bird]

Re: B7800 Won\'t start

</font><font color="blue" class="small">( I should add that when I first tried to fire it up each of these times it fired for about 1-2 seconds then died out which leads me to fuel starvation??? )</font>

Alan, there may be no connection, but this sure sounds like the embarrassing "problem" /forums/images/graemlins/blush.gif I had with my B2710 when I first got it. And like you, it only happened when it had been running, shut down, and restarted. I had posted on here about it, I called the dealer about it, etc., and then one day when it fired and died, I happened to notice that the instrument panel lights weren't on. And that's when I discovered it was operator error. /forums/images/graemlins/blush.gif When it fired, I turned the key loose too quickly and the spring was strong enough, it simply snapped the key back to the "off" position. In other words, I'd been starting it and unknowingly immediately turning it off. /forums/images/graemlins/blush.gif

 

[kubmech]

Re: B7800 Won\'t start

Alan, I'm not sure (can't remember) if your tractor has the continuous on solenoid or the shut down solenoid. If you have a large solenoid attached to the linkage near the injection pump this works through a time delay relay when shutting off the tractor the solenoid is powered to pull the fuel linkage to the off position. Then after approx 5 seconds it's depowered and retuirns the linkage to the fuel on position. I have seen where the linkage does'nt always return to the fuel on position due to the solenoid being a little cocked. Two bolts can be loosened that secure the solenoid and it can be repositioned so the linkage can return to the fuel on position after the solenoid depowers. You can check it by turning the key to the on position then off. you should see the solenoid pull the linkage to the off position then after a few seconds release to the fuel on position. If after it releases and you can pull the linkage further and the engine starts then you have found your problem..... One more thing, if the tractor has a fuel stop knob/lever make sure that's not causing a problem as well.

 

[Egon]

Re: B7800 Won\'t start

Bird:

That wasn't operator error. That was B7100 lag.

Egon