My Briggs and Stratton 3.5 HP lawnmower squeals when I pull the cord and start it. It will run fine for about 10 seconds until the engine ramps up and there is a loud squeal coming from the part that rotates when you pull the cord (Carburetor?) on the top of the engine. It almost sounds like it is seizing up. Any clue what is causing this?
If it sounds like it is siezing up it probbaly is. Have you checked or changed the oil?
Also, the "thing on the top" is probably your pullcord and clutch assembly. I dont think the overrunning clutch in there would squeal though.
Most likely you have a rid bearing that is going/gone.
I have seen this a lot in older B&S motors. Its a cheap part and is easy to replace if you know how.
Josh
Brian wrote:
meant ROD bearing not rid bearing.....my bad
perhaps your overruning clutch could be dried out. A simpler thing to do before replacing the rod bearing is to take your top cover off ( there should be a few 1/2 or 9/16 bolts holding it on. Once you lift that up (if your motor is like the one i am thinking) you should see a square oist sticking straight up. in the top of that should be a little plug with a tiny hole in it. You can pull that plug and try putting a few drops of oil in there and see if that helps. Sometimes those do get a little dry and make a little noisem but squealing after it "ramps up" makes it sound like it is out of oil or a bad bearing IMHO.
Let me know
Josh
snipped-for-privacy@hotmail.com wrote:
Sorry for my ignorance, but should I use regular 10W-30 oil or is there some sort of lawnmower oil I can get from Ace Hardware or Lowe's?
Yep any regular motor oil will do just fine.
Brian wrote:
Yes, it is the starter overrunning clutch. I have had that happen a couple times but haven't really tryed to oil one. For sure it is not a rod bearing. That would knock, not squeal.
Harry K
Yeah i was thinking that after i posted...if the rod bearing was spun and on top of the bottom one (in the cap) it might squeal a little...but i am lening twoards the clutch..oiling them sometimes works sometimes doeasnt....luckily they are easy to replace if need be.
josh
I'm going to take it apart tonight after work. Lawnmower place charges $20 to look at it, but the $20 goes towards the repair.
Does jerking on the rope, or banging your hand on the top of the engine, (only if moving pars are not exposed there.) stop or change the noise? That would suggest the starter mechanism needs lubrication.
Bob
In your case, it is $20 well spent. I don't mean to sound nasty, but if you don't know where the carburetor is, do you think you can re-assemble the clutch and spring mechanism properly and really save that 20 bucks?
You're probably right. If it's not a task that is not very straight-forward then I shouldn't attempt it.
Yep, I've seen this before. The repair technique follows:
Remove the three bolts that hold the motor cover on. Typically 7/16 wrench. Sometimes also a bolt to get the motor cover off the throttle cable.
Lift motor cover off.
In the center of the the flywheel is a clutch, which looks like this:
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Use a magnet to remove the five or six ball berrings, set them aside.
Use some solvent to clean the crankshaft which is now exposed. Solvent and cotton swabs to clean inside the almost-square part.
Lube inside the almost square part, with something that won't gum up. Silicone is good, or maybe silicone and dry graphite mix.
Slide almost-square part back on crankshaft. Replace ballb errings. Replace round cover. Replace motor cover, snug in the bolts.
Shuold be good to go for a few more years.
I've heard clutches squeal. To me, that's far more likely than a rid bearing failure.
The Briggs book calls for straight weight HD30 for most climates. But
10W-30 works fine. Please use a good brand, my fav is Castrol. Other folks like Pennzoil, Mobil, Quaker State, etc.I've done a couple. Really not a dificult task.
Oh, forgot. While you have the motor cover off. The engine is air cooled, so you'll be doing the motor a favor to clean off any dirt or dust.
Tip the mower onto the side, and drain the old oil out. Should take about 20 ounces of new oil. Oil change is cheap, and really helps the motor last as long as possible. Use good quality oil. 10-w-30 is fine.
I also charge $20 for advice.... (wink wink)
Dear Ed, Fortunately he doesn't have to reassemble the spring part of the mechanism. I wondered the same thing, him not kowing what a carb is.
Lawnmower guys says it sounds like the starter and the flywheel binding up. He says there is no clutch on this lawnmower.
which seems odd, because if this is a pull start there has got to be something that allows the crank to overrun the pull-cord assembly.
if there isnt one of those then this must not be one of the standard B&S motors I have worked on...I am having a hard time understanding how a pullstart motor would work without a clutch on the pull cord....
Josh
Brian wrote:
If it helps, it is a MTD model with a B&S engine. I'll post what is wrong with it hopefully tomorrow when I get it back. The repair didn't seem too straightforward so I decided to take it to the Pros.
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