B7100 Not Starting

boseephus

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Apr 3, 2012
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GA
Have a b7100 with D750-Engine. Glow plugs are heating and fuel getting to injectors. Can not get it to start. Dont know if it may be out of time or what any help appreciated. Thanks.
 

Big Kahuna

Member

Equipment
Kubota 2000 L3010 HST with Loader ,1992 B7100HST , 1979 B6100E & 2007 F2880
Dec 23, 2011
353
6
18
Homer City, Pa.
More information please? how did this happen? Turning over ? trying to fire?

Big Kahuna
 

boseephus

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Apr 3, 2012
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sorry...it will turn over but never really a promising hit. It has been sitting for a while but has good fuel. puffs smoke when turning over blackish color. I have pulled plugs and pulled decomp lever and turned over to try and clean anything out. Dont know what to do next. dont know much history about it, just bought it.
 
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76_Bronco

Member

Equipment
B7200 4WD w/FEL, 4' disc, 4' Brush Hog, 14" Plow, 4' Blade, JD 246 2 row Planter
Mar 28, 2012
182
1
18
Rainsville, Al
sorry...it will turn over but never really a promising hit. It has been sitting for a while but has good fuel. puffs smoke when turning over blackish color. I have pulled plugs and pulled decomp lever and turned over to try and clean anything out. Dont know what to do next. dont know much history about it, just bought it.
Make sure the decomp leaver is actually returning to the off position when you let go of it. There prone to stick from lack of use.
 

Stumpy

New member

Equipment
L175
Dec 1, 2011
848
3
0
NE Ohio
If it's been sitting for a while the fuel in the lines may have gone bad. I'd first take Bronco's suggestion then change the fuel filter and drain the fuel from the line up to the pump. Refill with fresh diesel and then give it a good long bleed. Failing something is definitely wrong and I'd do a compression check first. Depending on the store you should be able to rent one at Autozone.
 

Stumpy

New member

Equipment
L175
Dec 1, 2011
848
3
0
NE Ohio
A quick google turns up this page which suggests the factory spec is 412-469 psi. I'd give that a bit of leeway, a lot of things can carry compression ratios and they go down with age. As long as the numbers are above 350 and within 10-15% of each other I'd consider the rings and valves good.
 

Big Kahuna

Member

Equipment
Kubota 2000 L3010 HST with Loader ,1992 B7100HST , 1979 B6100E & 2007 F2880
Dec 23, 2011
353
6
18
Homer City, Pa.
Are you sure glow plugs are heating? When was it run last?

Big Kahuna
 

76_Bronco

Member

Equipment
B7200 4WD w/FEL, 4' disc, 4' Brush Hog, 14" Plow, 4' Blade, JD 246 2 row Planter
Mar 28, 2012
182
1
18
Rainsville, Al
How long are you heating the glow plugs? My B7200 in 80 degree weather needs at least 20 seconds of heating before it will start.
 

boseephus

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Apr 3, 2012
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took plugs out and grounded them to test and all got red hot. heating for sometimes 45-60 sec when trying to start. last time run was about a year or year and half.
 

bruceatlam

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Equipment
B20, FEL, box blade, flail mower
Aug 20, 2009
410
4
0
Camarillo, California
Check your compression ----- or an easy check, grab the fan belt and see if you can easily rotate the engine. If you can easily rotate the engine with the fan belt then back to check your compression --------
 

Stumpy

New member

Equipment
L175
Dec 1, 2011
848
3
0
NE Ohio
Ghhaaaa! Please make sure the engine is disabled by loosening injector nuts if you try that! Better yet remove the pipes from the injectors entirely. Excellent way lose digits. My cousin's great grandfather worked on boats and engines all his life and made that mistake once working on a barge engine. He only lost his ring finger to the fan belt but that was enough to drive home the lesson with me. Fascinating guy actually, lived on what used to be a dairy farm on an island in the Thousand Islands and up til about 93 still cut hit 5 acres of grassy hills with an old Massey-Ferguson row tractor and drove his Vintage Lyman work boat across the river to pickup things in town.

Anyway I'm a little skeptical you'll be able to tell much with that method except perhaps the differences between the cylinders and it would have to be relatively large. Compression gauge would be more accurate and much safer. I'd try what I suggested before about the fuel filter and bleeding fresh fuel up to the injectors unless you can get ahold of a diesel rated gauge easily. I think you'll have to hunt for one for rent or borrow.
 

B7100

New member

Equipment
B7100,B7100 with Backhoe and FEL, Goldoni Quad 20
Feb 11, 2010
422
2
0
Wales
Is the fuel shutoff tap in the ON position,pointing down?
Also check you have a good flow at the injectors,crack each pipe union in turn,pull the decompresion lever so she spins real fast and see if fuel spurts out.
dave
 

boseephus

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Apr 3, 2012
18
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GA
well I have a compression tester but it only goes to 300#. I gave it a shot anyway. I removed the glow plugs and pressed the tester tight to hole as possible (not the best tester but its what I have at the moment) one cylinder gets only 120ish other 240 and 160?? Could this just be that Im not getting good fit with tester? if these numbers are correct what should I be looking for? I removed the head to check gasket and all seems well but before I am done will replace with new one just in case. Please help!!!!!!!!!!!!!!:confused:
 

boseephus

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Apr 3, 2012
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also feels like it is sucking through exhaust just a bit but its not blowing out intake or anything. intake has good suction to it. dont know if this matters just trying to get all help I can. thanks
 

bruceatlam

New member

Equipment
B20, FEL, box blade, flail mower
Aug 20, 2009
410
4
0
Camarillo, California
I think that your problem is lack of compression ---- I'm not sure that your "press and hold" gauge is the best but it looks like you can hold it in up to about 240 psi at least. So, I guess I believe the 120 and 160. It won't start with that compression. Now, you need to figure out why? Either the valves or the rings. Easiest to check valve clearances first.
 

birddogger

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May 29, 2011
433
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Pittsburgh
OK, that was a "dry" compression test; now lets do a wet test. Same process but squirt a couple teaspoons of motor oil in each hole and turn it over for a second before you read that hole. USE SOME EYE PROTECTION it will probably blow that oil back at you. If they all test much higher that is wear, if they test a little higher the rings are rusted. If it seems that the rings are rusted then squirt a bunch of Kroil in each hole and walk away for 3 days, then test again.
 

B7100

New member

Equipment
B7100,B7100 with Backhoe and FEL, Goldoni Quad 20
Feb 11, 2010
422
2
0
Wales
You really need a screw in compession tester for a diesel engine,its unreliable getting a leak proof seal by holding a rubber ended tester at diesel psi
dave
 

boseephus

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Apr 3, 2012
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GA
So I decided to remove engine and give it a look over. I am having head and valves inspected and am planning on atleast new piston rings while I am in there. Should I replace bearings also? Like I said if I see something it will be replaced but want to do a little preventive maintenance while in there if need be. Where is a good place to buy rings and bearings? I have seen them online for 1/3 the cost of kubota dealer. Thanks.
 
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