Kohler SV730s with frozen crankshaft

[bertsmobile1]

A top bearing failure is always low oil.
Usually the oil level gets low and then the mower is run along a slope.
This means that the oil pump inlet is above the level of the oil.
There is about 1 to 3 minutes worth of oil in the top bearing housing.
So a slope that you have mower 50 times with out problems will suddenly cause an engine seizure because the oil, while being within the two oil level lines, is just that tiny bit too low.
On vertical shaft engines the sump is a big flat pan so a very small difference in the slope can make a very big difference to the oil level at the pump.
I have even seen a case where a partially flat tyre allowed to oil to sit lower than the pump inlet screen.

 

[RISKY]

Hi thanks for your reply mate ! yes i agree it was no oil to the top end but wanted to know if it was a blocked filter or crap in the pickup not just out of oil
so my engine was about the same as this when i brought and had a fair oil level and all they had was flat ground !
everything else on this engine was in great shape the rings and boars where great for 265 hours no leaking valves cam and everything was spot on ! so i through its worth fixing
so i put the crank on the lathe and polished it up ! i was worried more about the alloy in the top end but after a polish as well and cheeking for wear it was very close to spec !
now the only thing that i can see that would cause an oil issue was the tube that runs from the filter to the crank was very loose about 4mm play ! i only have 4 hours on this engine after putting it back together so will see if the block holds up for the long term but its running great and no noises !

 

[bertsmobile1]

Congratulations.
The cranks very rarely are damaged as they pick up alloy.A quick dunk in cold acid usually cleans them up nice, followed by a polish.
It is wear in the case that causes greif, as that is where the alloy came from in the first place.
Had several turn up in boxes where the DPO's had hammered the end of the shaft, wrecking the threads because it was stuck.
Worst one was a clot who pressed the crank out of the case cold and managed to put a .060" gouge the full length of the upper bush area.
We ended up filling it with Davcon, I was a bit dubious but it is still out there mowing so it must have worked OK.

I would have been inclined to run it for a few minutes without the top seal in place just to check it was getting oil to the top.
The other thing that kills them is running the engine at less than full RPM.

 

[qphone]

My sv725 has the same problem. I tried PB Blaster, WD40, acid…none of them work.

 

[bertsmobile1]

My sv725 has the same problem. I tried PB Blaster, WD40, acid…none of them work.

Welcome .
You want to start a new thread so you do not get confused with either Risky or James ?
Then state EXACTLY what you are trying to do so we can make useful suggestions

 

[qphone]

Welcome .
You want to start a new thread so you do not get confused with either Risky or James ?
Then state EXACTLY what you are trying to do so we can make useful suggestions

Thanks, I'll.

 

[Greg R]

I've got the same issue...PD blaster for 2 days, hammering (with Wood between) and it will not budge. Did you get anything to work?

 

[MidnightMechanix]

I just had a similar failure 20hrs after rebuilding the engine. While I know the engine was very full of post break in oil with a fresh filter, I’m assuming either my oil pump wasn’t working well or some gunk must’ve clogged up the crankshaft oil port.

Just curious if you had a way to check the oil pump (old style)

 

[bertsmobile1]

Midnight
These posts are a year old so good chance the posters have moved on
The quick & dirty way of checking the oil pump is to loosen it a little , remove the dip stick and plug leads then crank the engine.
If oil spurts everywhere then the pump is working .
The bulk of lubrication in a mower engine is splash but unless we know what engine you have we can not give you any useful information .
One persons failure is rarely another persons failure .

 

[MidnightMechanix]

Midnight
These posts are a year old so good chance the posters have moved on
The quick & dirty way of checking the oil pump is to loosen it a little , remove the dip stick and plug leads then crank the engine.
If oil spurts everywhere then the pump is working .
The bulk of lubrication in a mower engine is splash but unless we know what engine you have we can not give you any useful information .
One persons failure is rarely another persons failure .

SV725, same setup and parts as the SV730 the post is about.

In his photos above, the tan piece with the gear is the oil pump. The oil pump is internal and needs to be installed in the bottom bell to seal against outside of the displacement gear. While you could potentially drive it with a with an impact/drill and socket while submerged in oil, it would be hard to see if it’s building the proper pressure to lubricate the bottom busing, crankshaft channel and to the upper busing.

That’s why I was wondering if he had a way to test it specific to the post model. A post mentioned running the mower without the upper seal in place. That sounds like it would be a mess to me and would still require an almost full tear down if it’s not working.