843 Bobcat Perkins Question

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Christac

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Sep 15, 2020
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Looking at a 843 Bobcat with a Perkins motor and my question is are the perkins motor any good? Thanks
 

Tazza

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I have known a few people that owned an 843 with a perkins, they are a very good motor, i would't have any issues with buying a machine with one in it.
 

foton

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I have known a few people that owned an 843 with a perkins, they are a very good motor, i would't have any issues with buying a machine with one in it.
I know it is apples and oranges but I have a 74 hp perkins in my jcb 214 backhoe, great engine.
 

jp8775

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I have a 843 with a Perkins 4-154 engine. (Serial #5026-m15417) When I bought it the oil light was on all the time but it did not make any funny noises and the previous owner said it was always on for the two year he owned it. Put in a new oil pressure switch did not change. If I disconnect the wire from the oil pressure switch light goes out so it was not wiring. Next I put a oil pressure Gauge in it to test. It has about 5lbs at idle and 12-17 or so when I rev it up. No metal in the oil and does not rattle or anything. Some people have told me Perkins with High hours on them have low oil pressure but if it is not making noise don't worry about it. Should I? 7000 hours if it has never been rebuilt which I doubt no way to tell. If I do rebuild it where do I get engine parts thinking maybe just bearings and oil pump since it runs fine? Most everything that bolts on the pout side has been replaced. I got it for real cheap and will sell it when I am done. 1985 they say at Bobcat, is this a series 100 or 200 engine. Makes a difference for parts?
 
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foton

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if it starts easily your compression must be good enough, I would guess new mains and rod bearings if you were so inclined or just run it maybe switch to a straight 40 wt engine oil. but if it starts to make noise rebuild.
 

ajwgator

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jb8775 It would seem to me that the 5 psi at idle and the 12-17 psi would be enough to put out the oil light. Are you sure you got the correct oil sending unit? Or maybe the port that the sending unit is in is blocked not allowing the pressure to get to the pressure switch. Removing the wire from the pressure switch usually interrupts the path to ground for the oil light. See if the light comes back on when you just ground out the wire you removed from the pressure switch.

I too have a 843 with a Perkins 4-154 engine (S/N is #5026-M-16044) with a lot of hours on it. Mine has a lot of blow by when running. Its hard to start when cold but starts OK when its at operating temperature. Glow plugs don't seem to help when cold but I did replace them all. I know the previous owner used starting fluid on it so I'm sure the compression when cold isn't enough to fire it up. I've never checked to see what my oil pressure is so I don't know what is normal but my light goes out after I do get it to start. I'm looking to just bit the bullet and pull the engine and overhaul it. As far as parts are concerned... only use Bobcat dealer as very last resort. Massey tractors used this model Perkins too. I've seen complete rebuild kits on Ebay that were not that expensive.

jb8775 where are located?
 

jp8775

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jb8775 It would seem to me that the 5 psi at idle and the 12-17 psi would be enough to put out the oil light. Are you sure you got the correct oil sending unit? Or maybe the port that the sending unit is in is blocked not allowing the pressure to get to the pressure switch. Removing the wire from the pressure switch usually interrupts the path to ground for the oil light. See if the light comes back on when you just ground out the wire you removed from the pressure switch.

I too have a 843 with a Perkins 4-154 engine (S/N is #5026-M-16044) with a lot of hours on it. Mine has a lot of blow by when running. Its hard to start when cold but starts OK when its at operating temperature. Glow plugs don't seem to help when cold but I did replace them all. I know the previous owner used starting fluid on it so I'm sure the compression when cold isn't enough to fire it up. I've never checked to see what my oil pressure is so I don't know what is normal but my light goes out after I do get it to start. I'm looking to just bit the bullet and pull the engine and overhaul it. As far as parts are concerned... only use Bobcat dealer as very last resort. Massey tractors used this model Perkins too. I've seen complete rebuild kits on Ebay that were not that expensive.

jb8775 where are located?
Waconia Minnesota. If I ground it out the light does go on. I replaced the tee that the pressure unit goes into. I did get a 8 psi switch at least I would know if I lost pressure have not installed it yet. There are two 4-154 engines as far as parts 100 and 200 series I assume this is a 200? It starts easy with glow plugs that were not even hooked up when I bought it and the owner used starting fluid. When I hooked up the glow plugs it starts insanely fast. Bob Cat said its supposed to have 60 psi at full running power? I have not seen that anywhere in print. 612-327-3490
 

ajwgator

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Waconia Minnesota. If I ground it out the light does go on. I replaced the tee that the pressure unit goes into. I did get a 8 psi switch at least I would know if I lost pressure have not installed it yet. There are two 4-154 engines as far as parts 100 and 200 series I assume this is a 200? It starts easy with glow plugs that were not even hooked up when I bought it and the owner used starting fluid. When I hooked up the glow plugs it starts insanely fast. Bob Cat said its supposed to have 60 psi at full running power? I have not seen that anywhere in print. 612-327-3490
I'm in Versailles Kentucky. My 4-154 is a 200 series. Since ours are pretty close together serial number wise I would assume yours is too but they only way to be sure would be get the engine serial number and have a Perkins distributor verify that. I doubt that Bobcat would use two different series Perkins so close together in S/N#'s.

Seems the manuals say to use the glow plugs any where from 45 to 90 seconds when first starting an ambient temperature engine. Once at operating temperature the glow plugs aren't needed.

By the way, have you seen this thread in here? Similar in a way to our problems.

https://www.skidsteerforum.com/threads/843-perkins-4-154-smoking-problem.60448/
 

jp8775

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I'm in Versailles Kentucky. My 4-154 is a 200 series. Since ours are pretty close together serial number wise I would assume yours is too but they only way to be sure would be get the engine serial number and have a Perkins distributor verify that. I doubt that Bobcat would use two different series Perkins so close together in S/N#'s.

Seems the manuals say to use the glow plugs any where from 45 to 90 seconds when first starting an ambient temperature engine. Once at operating temperature the glow plugs aren't needed.

By the way, have you seen this thread in here? Similar in a way to our problems.

https://www.skidsteerforum.com/threads/843-perkins-4-154-smoking-problem.60448/
Thank you you have been help.
 

BG Scapes

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Oct 13, 2021
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I have a 843 with a Perkins 4-154 engine. (Serial #5026-m15417) When I bought it the oil light was on all the time but it did not make any funny noises and the previous owner said it was always on for the two year he owned it. Put in a new oil pressure switch did not change. If I disconnect the wire from the oil pressure switch light goes out so it was not wiring. Next I put a oil pressure Gauge in it to test. It has about 5lbs at idle and 12-17 or so when I rev it up. No metal in the oil and does not rattle or anything. Some people have told me Perkins with High hours on them have low oil pressure but if it is not making noise don't worry about it. Should I? 7000 hours if it has never been rebuilt which I doubt no way to tell. If I do rebuild it where do I get engine parts thinking maybe just bearings and oil pump since it runs fine? Most everything that bolts on the pout side has been replaced. I got it for real cheap and will sell it when I am done. 1985 they say at Bobcat, is this a series 100 or 200 engine. Makes a difference for parts?
I have an 843 about 6985 hours . I noticed the oil light flickering after unloading from the trailer . I had this problem on an f250 and it ended badly . If the switch isn't bad I would guess its probably sludge slowing the flow from the pickup tube . On mine I recently changed the oil after running it for 20 minutes with about 24 oz of diesel fuel in the motor , then filled it up with fresh oil and more diesel and dumped it again after another 20 minutes idling. Finished by changing the filter and filled it up with new 15/40 .
Oil light has stayed off for a few weeks now . A couple days ago I adjusted the valves and noticed how clean the rockers were !
 

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jp8775

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Dec 24, 2021
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I have an 843 about 6985 hours . I noticed the oil light flickering after unloading from the trailer . I had this problem on an f250 and it ended badly . If the switch isn't bad I would guess its probably sludge slowing the flow from the pickup tube . On mine I recently changed the oil after running it for 20 minutes with about 24 oz of diesel fuel in the motor , then filled it up with fresh oil and more diesel and dumped it again after another 20 minutes idling. Finished by changing the filter and filled it up with new 15/40 .
Oil light has stayed off for a few weeks now . A couple days ago I adjusted the valves and noticed how clean the rockers were !
I will try flushing the oil system that sounds like a good idea!
 

imtools

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Feb 19, 2014
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My Perkins 4-108 has works well but there have been issues. The crankshaft oil seal at the accessory end of the motor won't stop leaking, even after replacing the seal several times and even sleeving the journal on the crank. Recently I read in a marine forum that it could be due to the way this end of the motor is mounted and that it causes cover to shift, sending seal off center. I am going to try rectifying this.

Another comment I have to what I've read above is NEVER USE STARTING FLUID IN A DIESEL. I believe it is ultimately what caused my crankshaft to break into 3 pieces. Amazingly enough, it ran for probably a half an hour with it being broken, albeit quite noisily.
 
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