Replacement engines? B7100 (not HST)

[grizzdbear]

Hi from OZ. Just need a bit of tech help. My B7100 manual (not HST) is a fabulous unit for general small farm work but the D750 engine is now getting a bit tired. (Using a 3' slasher on highest speed PTO speed even with slasher on the highest rise height it doesn't take long for the poor girl to overheat and boil). Have been quoted AUS$3,000 for complete engine rebuild with new injectors. Have sighted a number of low hour D950 3cyl diesels in stationary engines driving generators and welders. Does any-one know if the D950 will fit OR of any web site where I can find what 3cyl (refer slightly higher HP) Kubota engines might be suited as a replacement.

 

[Bellinghamster]

I put a D950 in my B7100. It came from an Onan marine generator.

The Onan Marine D950 didn't have a front PTO shaft, but the front pulley had 3 tapped holes that I fab'd a stub shaft to bolt up to. The oil pan (and oil pump pickup) were deeper but swapped easily. The front cover was quite different with the oil filter on the other side which interfered with the frame. I put a remote oil filter on as a work-around. The front cover couldn't be swapped from the D750 because the cooling passages in the block are different. The cooling plumbing had to be all custom made from copper pipe fittings to fit up to my old radiator - the in and out of the engine block (since it has a water pump) are in different places. The flywheel and starter were bigger but swapped over.

The hydraulic pump swapped over easily, bellhousing bolts matched up... all in all not too bad, but if I had it to do again, I'd probably try to find one with the matching front cover. Also the governor in the injector pump has tighter regulation since it was made to run at constant RPM (making 60 hz AC). I'm not sure if it could be adjusted to soften it up a bit. I could probably swap my old injection pump in, but didn't want to mess with timing.

D750, D850 and D950 engines should all fit... I'm not sure about a D650. I've heard D750's are used in those portable lights they use on construction sites (highway construction), and at least one person I conversed with had swapped one in to his B7100.

 

[Dennis]

Hi from OZ. Just need a bit of tech help. My B7100 manual (not HST) is a fabulous unit for general small farm work but the D750 engine is now getting a bit tired. (Using a 3' slasher on highest speed PTO speed even with slasher on the highest rise height it doesn't take long for the poor girl to overheat and boil). Have been quoted AUS$3,000 for complete engine rebuild with new injectors. Have sighted a number of low hour D950 3cyl diesels in stationary engines driving generators and welders. Does any-one know if the D950 will fit OR of any web site where I can find what 3cyl (refer slightly higher HP) Kubota engines might be suited as a replacement.

Are you sure it's not the cooling system needing attention? My B7100 has done about 3000 hrs and can still run at full revs driving a 4 ft slasher ( one inch off the ground)through 3 ft thick grass all day, without overheating.

It previously overheated when worked hard ,until I flushed the cooling system, replaced hoses and got a new radiator cap.