Lawnmower help

Tradarcher

Well-Known Member
Joined
Mar 20, 2005
Location
Creedmoor, NC
I've got a Toro Wheel Horse with a B&S engine. I have good spark. Checked it by pulling the plug out and grounding it while I turned it over. It's bright white. I have gas because I squirted some into the chamber. I even got it to backfire through the carb twice. The exhaust is not blocked as far as I know because the screen is still covering the opening. I suppose I need to pull it though. It cycles great when the spark plug is pulled but when I put it back in it acts like the compression will not let it turnover. It will turn freely though one cycle but won't through the other cycle. That sound like something has gotten in my exhaust?
 
Not sure if I completely understand what you are describing, but to me it sounds like you might be flooding the engine, maybe you poured too much gas into the cylinder or are priming it too much when you go to start it?

[EDIT]

A "Wheel Horse" is a riding mower, not a push mower right? Guess it wouldn't have to be primed then... sorry. When you pull the plugs, will it turn over easily? Or does it still sound weak? Could also be a starter.
 
Sounds like you've got a weak battery. The other thing I'd check is whether or not the Woodruff key on the flywheel has sheared. Pull the plastics until you can see the nut that holds the flywheel on. Pull the nut and check that the keyways are alligned. I've fixed several mowers simply by replacing this key. You can get 'em at Lowe's or HD. If it's sheared, have fun getting the flywheel off! It's a taper fit, and it's gonna be tight. You'll probably need a puller of some sort.
 
I have a strong battery. I charged the mower battery good and I'm using the boat battery as well. It's not the battery. When I pull the plug it turns over freely and quite fast. When I put the plug back in it doesn't turn freely. It reminds me of trying to start a 4 wheeler using the pull start rope without opening the compression release engaged.
 
Through the years I have replaced probably hundreds of those Key-ways. I always take a long screwdriver and put pressure on the flywheel as if trying to pry it up, take a hammer and tap the side of the flywheel, where the pick up is and it comes right off. I am sure they make a tool for this but this always worked for me. That key way is what sets the timing on a Briggs, so if it is still in one piece but slid just a little, it will keep it from cranking. The back firing trough the carb is usually a sign that this is the issue.
 
Yeah after doing some reading I think that may be the problem too. Timing is off and that's why it backfires (frontfires?). What's so odd is that it has been sitting since early October. It ran fine when I parked it. I would think that I would have to hit something in order to break the key. You know, sudden stoppage.
Luckily when it backfired I had the air cleaner off. If not then it would have blown it to bits. Freaked me and the dog out.
 
mower

Just my $0.02 but From all the mowers I have worked on the spark is always blue not white. If it has the magnetic pickup on the flywheel gap may be to much
 
have you drained the fuel and replaced with fresh ?

I had to do that with my Troybuilt last week, gas was rancid, also had to pull the float bowl off the carb to clean the crud out of it, as the float was also stuck. ( 18hp B&S twin ) and was flooding the carb and cyls, and yes, it got hard to turn over do to being flooded.

damn thing runs like a top now, mowed thru 1.5 foot tall grass with it to day ( thick grass over septic lines ) hardly bogged down at all, unlike the old Murray 12.5hp one lung that it replaced. Which I also had to do this same service too about once a year as well.
 
I guess I'll be doing that tomorrow. I've had this thing for years and it never complained about the gas going bad over the winter before. I'm going to charge the battery and get a new plug and new gas and see what that does. Each time I pull the plug it is dry though. Carb probably needs to be drained.
 
Kevin Lawler said:
I guess I'll be doing that tomorrow. I've had this thing for years and it never complained about the gas going bad over the winter before. I'm going to charge the battery and get a new plug and new gas and see what that does. Each time I pull the plug it is dry though. Carb probably needs to be drained.
Click to expand...
IMHO & years of abusing lawn mowers. it sounds like years of not using gas stableiser. clean the needle and seat in the carb and see if that fixes it...
 
I hate to tell u but that sounds exactly like what my mower was doing. Does it have 1 or two heads? I pulled my heads on my 18.5hp briggs and one the rods were broke. It would turn over and back fire like the timing was off. We pulled both heads and turned the flywheel with our hands and cycled through the motor. just my .02. Hope this helps
 
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