Anyone know about replacing/repairing lawn mower engines?
 

My mower just went kaboom, literally. A large chunk of metal went shooting out of the side as I was mowing my yard. I really like the mower, and a similar replacement would be around $300. Does anyone have experience with replacing a mower engine? It's a Craftsman self propelled mower with a Briggs&Stratton 6 hp motor. I've found several places that sell a short block for around $150, which is fine, but I've also seen several places that sell complete new 6.5hp motors for the same price. I'd rather just plug a new motor on there if possible, but I don't know about compatability issues. Anyone have experience with this sort of thing?

Re: Anyone know about replacing/repairing lawn mower engines?
 

Done it...pull the motor first, make sure all the interface parts (engine mount, cutting blade gearinging, shaft, etc.) between the motor and the lawn mower are not damaged.

If they are, order from Craftsman.

In general, look up the motor on any number of web sites, match and replace with the rigging from the old engine..

The mower I did this on had some throttle cable issues and other nits, but nothing my son didn't correct me on.

I've also done it on larger riding mowers...same deal.

Briggs motors are very easy to work on.

Just pull off all the ancillaries and transfer them over. Buy a pack of rubber diapragms for the carb. You'll need them.

You should fix it. Umm humm.

http://forums.pelicanparts.com/uploa...1149726987.jpg

A little bit of advice: don't work on the 'mower while the motor's running.

No problem working on the mower while the motor is running, there is a nice large hole in the block preventing that from happening.

While cooking out on my back porch, I pulled the motor and stripped it down to the block. (mmm... used motor oil goes well with Italian Sausage!) The connecting rod broke apart at the crank. Blew a hole 2" by 2" in the side of the block. I'm not sure why, everything else looked in very good condition. It could have something to do with the 18" masonry bit the I ran over a few weeks ago that the cable guy left in my yard. Oh well, now I know how to take apart a B&S motor. It is very simple. Now I need to find the correct short block.

Hey, its air-cooled! Put a set of SSIs on it and a K&N filter! Throw a Bosch platinum plug in for good measure.

RobertCoats writes books about it. He is rearly seen in the OT but is a frequent flyer on the tech bored...

I had a really nice mower in the Northeast, A Goodall with an Aluminium deck and real greased bearings in the wheels. The engine quit. I found that our local garbage transfer station, the garbage guy rescued things like this. I replaced my engine for free.

Then I stripped out the spark plug hole...and replaced that engine for free!

If you really like the mower, replace that B&S motor. It will just keep going.

Damn--I had the same thing happen yesterday on my Craftsman. No warning, just 2 knocks and then kablooey, then all the oil leaked out!

Just what I need another freakin' project.

Check smallenginewarehouse.com. They have short blocks for around $40 and replacement motors for around $130. Much cheaper than a new mower! I was going to replace the short block, but after talking to the guy, I found out that I can put a better, higher hp motor on my mower for only around $130. Who doesn't need more power!!!!!

I am planning on tearing it down next weekend and seeing what actually occured--as I really like the mower, 6.75 HP mulching, self-propelled, and while I never babied it, I did tune it up every year and regualrly change the oil.

Thanks for the link:)

Small engines like these come in many configurations in regards to output shaft size, fuel tanks, throttle controls, exhaust etc. Find the model number of the engine id tag, then google it to find an exact replacement. Trying to mount a slightly different version of an engine like this is often doable, but probably not worth the effort if it is only a $300 push mower.

+1

Re: Anyone know about replacing/repairing lawn mower engines?
 

As others have suggested, a short-block or full replacement engine is a good choice. A key point for a proper fit is the crankshaft length. Measure the distance between the engine base and the tip of the crank. Make sure the new engine is identical; you don't want the blade to ride too high or low inside the mower deck, for obvious safety and cut quality issues. "One size" does not fit all.

Don't be too quick to put on a more powerful engine, as the additional output of HP and torque could overstress the mower deck and blade. Lawnmowers are built to a price point, and costs are tight. You can be assured if the original engine was 5 hp, the rest of the the mower was built to handle 5 hp, but not more, because it would increase the costs.

Next, check control lever connections. Assuming you have a standard mower, with a flywheel brake (a.k.a. "deadman") lever, verify the cable that controls it is correctly adjusted and shuts down the engine when you release the lever.

Double-check the thottle cable/lever (if present) and make sure the throttle is actually wide-open when you have the lever in the FAST position. Otherwise, the blade will spin too slow and you'll have cut quality problems.

Find out the torque specification for the blade bolt(s) and use a torque wrench; don't leave off any blade hardware, such as a curved washer. And, while it may sound silly, make sure the blade is installed in the right direction...it's a common error to get it in upside-down.

-Robert "lawnmower/generator/tiller/snowblower/string trimmer, etc." guy

my work here is done...

Funny my neighbors craftsman mower started knocking and the next time he used it the engine siezed up. He is getting a honda to replace it