cat 226b2 melted nylon flange and hard to start

[Dale228]

Hello all have just joined
I have a customer with a cat 226b2 Highflow out on a piggery
got called out for no hydraulics which i diagnosed as the nylon coupling plate
pulled the pump and found that the nylon plate where the teeth are had been melted out (pretty impressive but very concerning as to why it has melted not just sheered the teeth off)
replaced that and fit everything back together everything was labeled and marked
went to start the bobcat and it wouldn't start tried to glow it and also tried either whilst cranking it pumps black smoke out the exhaust (huge amounts to the point of you cant see in the shed)
i have checked the intake for restrictions checked the turbo and exhaust checked the lift pump and fuel stop solenoid also checked all the governor setup everything has tested fine. its almost like the hydraulic pump is putting a load on the motor from the get go
i did manage to get it to fire and run the other day the right hand joy stick works perfect the left hand joystick has a delay when you try to drive forewards and backwards the same goes for when you turn left and right but it doesnt overshoot when you go back to center
when it did fire it sounded like the turbo started spooling straight away (like under load) but when it does fire it chugs along for 10 seconds before blowing a heap of smoke then running normally no smoke once it is running unless you rev it up


Previous to the hydraulics stuffing up it was starting perfectly fine and very limited smoke except for the day the nylon flange melted apparently it was really hard to start that day aswel and it started fine when i went to diagnose the flange because the hydraulics were obviously no longer being driven then back to hard starting now that the new flange is fitted

struggling to find any information on the machine to try help dignose it
picture attached is of the melted flange


serial number is CAT0226BTMJH14046

 

[Nige]

"i did manage to get it to fire and run the other day the right hand joy stick works perfect the left hand joystick has a delay when you try to drive forewards and backwards"

Have you considered the possibility of something in thre hydrostatic system loading the engine and thus preventing it from firing off when cranking.?

 

[Dale228]

Yep i am thinking thats where the issue might be but im struggling to find any testing procedures to pin point the problem
Im wondering it its a blocked return line somewhere or a swash plate stuck and not returning to low flow

The left hand joystick has flow to the supply line as soon as you crank it and the return line has nothing coming out of it unless you try drive it forward or back then when you go back to centre it lets a little bit of oil out then stops again