help me repair an old snowblower engine

March 7, 2015 1:09 PM

When we moved into our house, we found an old Atlas 5HP snowblower in the basement. It looks like it hasn't moved in 20 years, and of course it doesn't start. I'm a bit of a tinkerer and would love to learn how combustion engines work while fixing (or attempting to fix) this one.

I've never worked on a motor before and have only basic, picturebook knowledge of how they work. However, my understanding is that all the components are relatively simple, and there's really only so much that can go wrong with a small engine like this. It would make a nice little project, and if I screw it up, then there's really no harm done. And if I succeed.... well, I'll be the savior of the neighborhood come Snowpocalypse 2016.

What kinds of specialized tools, solvents, greases and oils should I have at the ready before digging in? Are there any manuals about general engine repair that would guide me on my way?

Thanks, MeFi!

posted by joebakes to Home & Garden (7 answers total)

My next door neighbor's was old and forgotten and ended up only needing fresh oil (which I think I had to prime in some way specified on the unit) and gas. You might actually get lucky.
posted by DirtyOldTown at 2:14 PM on March 7, 2015 [2 favorites]

You will probably need to clean the carburetor. Look on the motor for a metal plate listing the company, model number and serial number so you can buy a manual for it. Briggs and Stratton has some good tech manuals for sale for even older motors. They also have some PDFs at their web site.
posted by rfs at 4:10 PM on March 7, 2015 [1 favorite]

Best answer: As you have suspected this isn't rocket science - and it can be quite gratifying when it starts on the first pull. I just did a full overhaul on mine this year - probably 20 years old but going strong. Things to check/replace:

1) Oil.
2) Spark plug. Make sure you pull the connection to the spark plug when you are working on the snowblower - chance of it starting is small, but if it did you would have a real problem, disconnect the plug just to be safe.
3) Carburetor - don't clean or rebuild, replace it. You can find replacement carburetors for these kinds of engines on amazon for less than $20 - usually the same price as the rebuild kit. Just make sure you buy the right one for your engine.
4) Check the belts - replace if worn. Again check twice before you order to make sure you have the right length
5) Adjust the belt tension. There will be a tension pully - over time (or sometimes even new) you will need to adjust the pully to ensure you have enough tension on the belt that it won't slip.
posted by NoDef at 5:12 PM on March 7, 2015 [4 favorites]

Sounds like a fun project. Small engines are indeed fairly straightforward: spark, fuel and compression should make 'em go. NoDef has good suggestions, IMHO. I might add draining the gas and perhaps cleaning/replacing the fuel filter. And definitely sort out the model number and search for an exploded parts diagram (like this).

I've gotten a lot out of Paul Dempsey's Small Gas Engine Repair, and his two-cycle specific book as well.

Good luck!
posted by farmerd at 5:51 PM on March 7, 2015 [2 favorites]

Something I have found on old engines that are indifferently stored is they develop a rusty gas tank. Just replace it if possible. Trying to de-rust a gas tank is...difficult. You can probably just replace it with something similar if the exact replacement isn't available.

It may be just fine-just take a look and see. If it is rusty the bits of rust will get in the fuel system and clog up the carburetor really good.

Also-don't forget the fuel filter-they are cheap and generic so just replace it, along with all the fuel lines-rubber rots over time and who needs a fiery snow blower?
posted by bartonlong at 7:49 PM on March 7, 2015 [1 favorite]

Response by poster: I think a fiery snowblower is exactly what I need. ;-)

Thanks everyone! I'm now able to go into this project with confidence.
posted by joebakes at 9:00 PM on March 7, 2015

These days with digital cameras/phones you can take pictures as you dis-assemble so that you'll be able to remember what goes where when you put it back together.
posted by mareli at 11:29 AM on March 8, 2015