Stihl Ms290 Oil Pump Removal

[Smitty]

I Have a MS290 Which is currently not pumping oil to the chain. I have been able to break everything down to the brake assembly sprocket where the breaks sit. The brakes and clips come off fine but the assembly the sit on I can't get to budge It looks like it takes a 3/4" wrench that fits but i cannot get it to move. The oilpump is reight behind it but I cannot get to it without moving the. Hope someone can help.

 

[Kevin]

Is the pump drive spring wire that engages the clutch drum intact?

 

[Rupe]

[ QUOTE ]
I Have a MS290 Which is currently not pumping oil to the chain. I have been able to break everything down to the brake assembly sprocket where the breaks sit. The brakes and clips come off fine but the assembly the sit on I can't get to budge It looks like it takes a 3/4" wrench that fits but i cannot get it to move. The oilpump is reight behind it but I cannot get to it without moving the. Hope someone can help.

[/ QUOTE ]

When you say brake assembly, do you mean the clutch? The brake would be the steel band that goes round the clutch housing.

You mention the brake and clips come off, that sounds to me like the clutch.

If so then the whole clutch assembly should come off, with a wrench. I'm not familiar with ms290 but if you say 3/4" then ok.

Its a reverse thread though, so righty loosy!! And you will need to jam the piston to stop it rotating.

The oil pump should be under that lot, if its the same as my ms260 or 440 ........

 

[Smitty]

Thanks for the help. Yes I was wrong it is not the brake assembly it is the clutch. I Can get right to the piston by taking the muffler off. I will give that a try.

 

[Tucker943]

I would try going through the spark plug hole as a piston stop. Do not try using the flywheel shaft to hold the crank in place to take the clutch off. I could tell you an ugly little story about doing it that way. The oil pump will have a plastic arm that goes forward and clips itself(male/female fitting) onto the oil tank. Be very careful not to break the nipple coming off of the oil tank when removing or installing the oil pump. That oil tank is the back bone of that model and if you break that nipple, just take the whole saw and throw it in the trash.
Best of luck.

 

[Rupe]

Yeah no need to take the muffler off!! Just remove the spark plug. If you have taken the muffler then no worries, either way you need to jam the piston. Most saws come with a small plastic tool for this purpose which you jam in the spark plug hole (or exhaust port, if you've gone that way) or you can buy a special tool but that screws in to the spark plug hole only.

If you don't have either of these then a length of rope will do. Small enough diameter to shove in above the piston. Shove enough of it in there to jam the piston in the down position.

In the field we've used boot laces for this in an emergency!! As long as no fibres come loose and get stuck in there.

Then crank the clutch assemble off, remembering the reverse thread. After that its all straightfoward, but be gentle!