Cleaning out the guts of a Stihl MS290

[Mutineer]

OK, my dilemma is that my MS290 is acting like a bad coil is causing hard start and poor running issues, so I got a replacement coil and took the flywheel cover off to dig in. The issue is that there is a thick build up of oil laden old sawdust and schmutz from 20 or so years of use inside the flywheel and coil chamber of the saw and I'm wondering if I can spray engine cleaner and then hot water in there to get everything cleaned out for assessment. I've scraped and dug out a lot of the boogery stuff but I have a bit of an obsession about cleaning everything off before I start. What is the rule of thumb from you seasoned chainsaw addicts?

 

[zak77]

I typically use compressed air to clean my saws. I get the bulk off then if it's real bad use a toothbrush to loosen the rest then blast with air again. The finish up with a rag soaked in mineral spirits to get the oil off.

 

[Mutineer]

Thanks, Zak77 but the nooks and crannies down inside that area are hard to get to with a toothbrush, it would be much easier to loosen up the debris with engine cleaner then blast away with my hot water hose in the garage, as long as I don't do any damage to any components.

 

[Jags]

Personally I would use compressed air over hot water.

 

[cygnus]

I usually blast it with carb cleaner...use the little tube on the nozzle to get the small areas. Might wanna wear goggles too.

 

[ericm979]

With the spray carb cleaner you can at least try to keep it off the crank seals and the ignition module, if you spray small amounts carefully instead of just hosing it down. A toothbrush or other small tool can help but most toothbrushes don't last long when exposed to carb cleaner. I'd do this rather than hosing it all down with engine cleaner and water. If you soften the goo you can gently scrape it out with a tool.

Getting carb cleaner in your eye is no fun so be careful.

 

[Highbeam]

Diesel fuel works surprisingly well as a cleaning solvent. With a brush. Some brake cleaners and carb cleaners can really screw up plastics. The crank seals are hard to replace. Don't screw them up. If you have lots of goo in there do you think your crank seals have already pooed the bed?

 

[Mutineer]

Thanks, Highbeam, for the ideas. That area of the saw has probably never been cleaned out and a little chain oil and exhaust oil gets in there over time and cakes it up, so I'm not at all worried about the seals dying. It's very obvious that this has been slowly accumulating after many hundreds of hours of use. Your comment about the carb cleaner and especially brake cleaners effect on some plastics is well noted, it seems that the regular Gunk engine cleaners are more benign than those heavier duty solvents.