MS251 oiling problem

[Cougar281]

I have a MS251 that I bought several years ago that has been running great all along, until about a month ago, it was submerged in a flood for about 15 minutes. The next morning, as soon as we discovered that there was a flood, I cleaned it up, dried everything out, WD40'd the cylinder (There was water inside) and let it sit wide open for several days. After putting it back together, it runs the same as it did before the flood, but the problem I have is it's not oiling the bar properly now. I've double-cleaned the bar, the oil holes are clear, the track is clear, and when I run the saw with the bar off, I do get a slight dribble of oil from the oiling hole, and running it with the bar and chain to see if I get 'splatter' on some cardboard, there does appear to be a small amount, but it's not like it was in the past, and I have used a tank of fuel and the bar oil is not even 1/4 used.

Does anyone have any thoughts as to why it was fine last time I used it before it was flooded, but now it's not oiling right afterwards? Could being submerged have caused some issue with the oiling system, or might this issue not be related to the flooding at all and just a crazy coincidence?

 

[bertsmobile1]

There is a filter inside the oil tank which may now be blocked by the water
Off with the bar & clutch
behind the clutch is the pump drive & pump and behind that is the oil pick up line & filter
Remember the clutch is left hand hread

 

[Hammermechanicman]

Remove the bar and chain. Remove the clutch drum E ring , washer and drum. Remove the clutch. It has left hand threads. Under the clutch you will find the oil pump worm drive gear. The metal arm on the gear should be tight on the plastic gear. If not it can slip causing low oiling. If the end breaks off the arm where it hooks into the rim of the clutch drum it can drag but not drive properly and cause low oiling. The oil pump is held in by a screw and easily replaced and not expensive. If the oil filter in the tank is clogged or the oil line is old and cracked it can cause low oiling. Easy answer is to just change the oil pump, worm gear, oil line and filter.

 

[Hammermechanicman]

Just happen to have a 251 on the bench. Customer thought it was a MS660. Tried to cut up a big tree with a dull chain and ran it so hard the clutch was slipping. Burned up the clutch, clutch drum, clutch bearing, worm gear, oil pump. The dark is scorched plastic. Clutch drum is blue and purple.

 

[Cougar281]

Thanks for the input. I sources a new hose, pump and worm gear, but they didn't have the 'filter'. When I got the filter out, all it was is a plastic screen, probably to prevent things like wood chips from being sucked up, but it was clean. replaced it all and I'm still not sure if it's oiling right... but I'm not sure there could be anything else that would cause it to not oil right. Unless there's a vent somewhere that's not functioning properly and preventing the pump from flowing properly due to building up a vacuum.

Hammermechanincman - Yikes! A small area of the plastic cover you have removed got hot enough on mine to melt due to the chain/bar temp, and the side of the bar that was down has some bluing due to the heat, but nothing as bad as that! The bar getting as hot as it did is what 'tipped me off' that something wasn't quite right.

 

[Hammermechanicman]

Thanks for the input. I sources a new hose, pump and worm gear, but they didn't have the 'filter'. When I got the filter out, all it was is a plastic screen, probably to prevent things like wood chips from being sucked up, but it was clean. replaced it all and I'm still not sure if it's oiling right... but I'm not sure there could be anything else that would cause it to not oil right. Unless there's a vent somewhere that's not functioning properly and preventing the pump from flowing properly due to building up a vacuum.

Hammermechanincman - Yikes! A small area of the plastic cover you have removed got hot enough on mine to melt due to the chain/bar temp, and the side of the bar that was down has some bluing due to the heat, but nothing as bad as that! The bar getting as hot as it did is what 'tipped me off' that something wasn't quite right.

The round silver thing slightly above and to the right of the bar stud is the oil tank vent part number 1128 640 9100. They usually fail by leaking oil when saw is stored. It is a spring loaded ball check. Make sure the small hole is clear. If vent is not working it will usually stop oiling after a few mins of running.