[maalu]

Hello everyone...

I have a 6.75 HP Craftsman lawn mower (model no. 917.377912, about 8 years old). It quit working on the last day I used it this (last) fall, during the middle of mowing. I left the repairs till I needed it again, and this spring I tried to start it after taking care of the usual trouble spots (i.e. I drained and refilled the oil and changed the airfilter and spark plug). It did start up and I left it running for a while (to make sure that the fuel was OK; I was still using the fuel in the tank that was left over from fall). After about 3-4 minutes there was loud noise and the lawn mower stopped working. Now I am not able to start it up at all. Do any of you have any suggestions as to what the problem (and, if possible, the solution) is? I would be grateful for any help I can get...

[lotuseclat79]

Hi maalu,

First, I would get some fresh gas - i.e. never start a new season with old gas - dump the left over in your car so it can mix with a recent fillup. Also, always drain the gas left over from the season in your lawn mower's tank rather than let it sit in the line, tank and carburetor - it may have gummed things up inside the carburetor. Use a self priming siphon hand pump like you can get from Harbor Freight Tools online for a reasonable price - item 03878-0RYA (siphon pump kit) at $9.99 sometimes $4.99 when they have a sale on it their catalog. (at http://www.harborfreight.com ).

Sounds like it may have backfired, which may mean a carburetor problem. I do happen to know that the local Sears in my neck-of-the-woods has a discount if you bring it in before 5/1/08 - parts not included, or you could opt to try rebuilding the carburetor with a rebuild kit if they carry them (they probably do as that sounds like it would be a common problem for lawnmowers).

-- Tom

[Soundy]

I'll second all of what lotuseclat79 says there, but I'd be interested in a better description of this noise, as "a loud noise" could be a number of things.

Gummed up from bad gas is pretty likely in this situation, though.

[maalu]

It was not exactly the noise of a backfire; there was more of a metallic timbre to it. When the lawn mower stopped following this noise, I checked all the accessible (without dismantling the engine) rotating parts to see if anything had broken / worked loose, but I couldn't find anything.

If it indeed is a gummed up carburettor, I presume just draining the old gas out and refilling with new gas wouldn't be enough - I would have to take the carburettor aprt and clean it, right?

As always, thanks for your help...

[JohnWill]

I'm guessing you may have had an internal failure. The metallic noise doesn't sound good...

[Soundy]

Yeah, my thinking exactly. Worst case would be something like a broken ring or connecting rod. If it's a four-stroke engine, a broken valve spring or bent valve would be a close second. Snapped reed valve on a two-stroke would be a distant third (they're usually pretty easy to fix).

Does it still seem to have compression when you turn it over (ie. if it's a manual start, pull-start etc., is it hard to turn, or does it turn in "spurts") or does it just spin easily? The latter could be symptoms of any of the above.

[The Easy]

Get A Honda

[n2gun]

Originally Posted by The Easy

Get A Honda

And send more money to Japan