Mower engine help...
 

I have the opportunity to buy a lawn tractor with a Briggs 21 hp engine. The current owner has had the mower in storage for over a year. When he fired it up a couple of weeks ago it blew white smoke for a while.


He took it to a small engine shop and they said they've seen the same thing quite often and it's usually a fuel problem, possibly a carb problem. He put new fuel with sea foam additive and started it up. It's been sitting for a week to see if that will cure the problem.



Is this an expensive fix if the engine needs work? It's a really nice mower for the price, but I don't want to inherit a problem.

Those Briggs are pretty straight forward. If it was stored for that long then what fuel was in it had gone bad by then and possibly gummed up the carb. Worst case you'd need the carb cleaned or replaced if it didn't run well for a while. The best thing for it IMHO would be to start and run it every day for several days in a row to see if it clears up after a tank or 2 of fuel and seafoam. I wouldn't be scared of it.

Thanks. I've dealt with mower engines for a long time. I haven't had one sit around and have this issue. I know Briggs builds a solid engine and hope it's just a fuel issue.

Small engines dont play well also with ethanol and can foul a carborator in short order. Use premium ethanol free fuel. It can be hard to find sometimes but its worth it if you want those small engines to run year after year. People will store a mower thru winter with stable and not be able start the mower or runs then shuts down with smoking.

My life got eons better after I threw my mower away and hired that shit out. No worrying about winterizing the dumb thing. No mowing. Trimming. The good life.

Don't know, but it is a B&S. How long did it blow smoke? Till it warms up? Possible oil blowing by bad piston rings until it warms up?

Probably ethanol.

When I do on my Honda motors is drain the gas in the spring. If it’s gummed your probably need to clean the carburetor. It’s a colossal pain in the cock. I’d probably find the drain in the bowl and drain it out of the carb. Then put sea foam in and start and run it every day with a healthy amount of sea foam.

If you’re looking at buying it I wouldn’t. No way to know for sure.

Side note: I think the new ones are better but fat boy hates Bolts and Scrapiron motors.

Drain the gas
Pull the carb
Douche with carb cleaner
Douche with compressed air
Reattach
Run 91 octane every time

fuel system cleaner- VP fix it fuel
https://vpracingfuels.com/product/fix-it-fuel/?c=232

I started buying VP fuel for my small engines (Mower, snowblower, power washer).
No ethanol. I have left it in my snowblower for 9 months and never had a problem with it going bad. its expensive but 5 gallons last me a year.

https://vpracingfuels.com/product/4-...ne-fuel/?c=232

I knew I could count on CP for this.

It sounds like fuel might be the culprit. If that's the case I'm all over buying the mower.

I'll know more Saturday when he fires it up to see if the fuel purge helped.

Thanks for your help!

Keep us posted.
Good Luck

My 3 year old kohler fires white smoke everytime I start it. Nothing to worry about. Just always check the oil.

Just ordered this, Im hoping this counteracts the ethanol..cant get ethanol free gas anywhere close.

I was running VP MS 98 fuel (leaded) in our race karts (2 stroke). started using it (no oil mixed in) in the lawn mower and never had to drain it. Now I use it in everything.
I was a dealer for VP because of the race org I helped with. Still have an account so I buy the 4 stroke fuel and/or MS 98 five gal at a time. I also dump some 102 octane in the daily driver on occasion........ The difference is night and day vs 98 pump gas.

Look for a VP dealer in your area. They are around. Kind of hard to find sometimes. MS 98 works as good as the 4 stroke fuel. It has lead and I think it helps lubricate small engines.

I had a mower with a B&S motor on it; it would start doing the same thing.
could never figure out until I read the fuel petcock (on/off twist things) might be bad or mis-calibrated, and when in the 'off' position, could be slowly leaking fuel into the oil reservoir, thus eventually becoming 'overfilled' a bit, and would smoke on start up.

before I read up about that thing, it would alwyas - about mid-season each year- start smoking at start up etc. each winter I would change the oil etc, and the following spring, woudl be fine. then by July...smoke.

I switched out the petcock thing; voila. never smoked again.

take a whiff of the dip stick; if it smells like fuel, it might be a similar problem. that's what I did; took a whiff and yp...smelled a little like fuel. switch the petcokc thing out, changed the oil. problem solved.


my honda does it now too a bit. but I found it's just eaiser to change the oil when it starts doing it. since it's quick and easy on the push. but the 21hp motor...assuming it's a rider. might be easier to look into the petcock thing.
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