Toro Wheelhorse sputters under load

[jpilk99]

I have a Toro Wheelhorse that sat for a year and I’m trying to bring it back to life. Drained the old gas, got a new fuel filter, out on a new carb …and it starts right up and drives around in flat surfaces. But the minute I go up a hill or engage the mower deck, it sputters …assuredly because it’s not getting proper amount of fuel? Carb only appears to have one air/fuel screw and I’ve turned it out and in but no change.

 

[ultrarunner]

I've had some success adding seafoam to small engine fuel tanks correcting problems...

Picked up a like new mower that sat 4 years?

Ended up picking up a cheap replacement carb online because I wasn't able to cure whatever it was by taking apart and cleaning the carb.

I'm guessing fuel flow is good and the condition happens with and without the fuel cap in place in the case of a obstructed cap vent?

Weak spark can run fine until under load too.

 

[masseyrider]

Drain the gas. Put in some premium. I run premium all the time in smaller engines. Better for the engine and it takes longer to go bad if you don't use the machine often.
Put some good quality carb cleaner in and let it run for 15-30 minutes.
Your carb jet may have some residue from standing too long with the old gas and if things go well the carb cleaner may clean it out.
Sometimes works...

 

[Eagle1]

Check your governor... linkage and base settings. That is what keeps the RPM up when a load is applied.

 

[Gee Ray]

Put a fresh spark plug in it. If that doesn’t correct it, take the shield off the covers the magnet and take Emery cloth (sandpaper ) and clean the surface of the magnet.

 

[oldnslo]

Can you operate the choke when it starts cutting out to see if enriching the fuel mixture helps.

Does it idle smoothly?

If turning air mix screw made no difference that points towards a plugged fuel passage which is probably part of idle circuit.

 

[RandyT]

If running normal at idle but struggles under load I would be cleaning the carb, paying special attention to the main or high speed jet. Could involve part of the idle circuit, but either way needs a good carb cleaning.

 

[masseyrider]

If running normal at idle but struggles under load I would be cleaning the carb, paying special attention to the main or high speed jet. Could involve part of the idle circuit, but either way needs a good carb cleaning.

like I like to do, start out easy and work your way up the difficulty scale.
All fresh fuel and rich on the carb cleaner solution.
Run it for half hour at higher (not too high) idle so everything gets good and warmed up.
Sometimes that's enough without having to dismantle anything.

 

[jpilk99]

THANK YOU ALL!!!

Here's some notes:

I did drain the tank, blew out everything, installed new lines and new fuel filter.
Always use premium gas
Put in new spark plug
Put in new carb, though likely not 100% OEM match; $35 on Amazon - which I've had very good success with many other carbs
Did not put in Seafoam given everything above

Interesting that today, after reading some comments about applying choke while machine started sputtering, I was shocked to see that the engine basically cut out - stalled. I immediately pulled the choke off and it went back to standard running; which is sputtering under load. When on flat ground or going down hill, full throttle, it does ...great. Coming up hill or with PTO engaged, it sputters.

ODDLY, after mucking with the choke, I noticed that the sputtering faded away on lower throttle. I actually mowed the lawn a bit at maybe 70% throttle. As soon as I put the throttle higher it sputtered. And if I put it all the way up to choke, it just stops running.

Here's a video I just took:

 

[Richard001]

Check the oil level sensor. If the machine works on level ground and only has issues when on a hill, it's not a fuel issue.

 

[jpilk99]

It's not "only has issues when on a hill". If I"m on flat ground and pull the PTO for the mower blades, it does the same thing. It's when under load ....and high throttle (but I run all my other machines at full throttle).

 

[Richard001]

OK, then back to what others have said, fuel or poor spark.

 

[oldnslo]

Does this model have one lever for both choke and throttle or two independent controls. If one is it adjusted properly so not running partial choke when you think still only throttle?

 

[RandyT]

That is a rich sputter not lean. List the model type code numbers from the engine so we can see what carb that engine has. May not be carb related could be a valve, camshaft issue.

 

[jpilk99]

That is a rich sputter not lean. List the model type code numbers from the engine so we can see what carb that engine has. May not be carb related could be a valve, camshaft issue.

Briggs model: 286H77 type: 0165 E1

 

[jpilk99]

Does this model have one lever for both choke and throttle or two independent controls. If one is it adjusted properly so not running partial choke when you think still only throttle?

Yes, only 1 control for both choke and throttle. I'll check adjustment! Thank you

 

[RandyT]

Briggs model: 286H77 type: 0165 E1

If this had the Nicki carb I would bet the high speed jet fell out. You said you replaced the carb from Amazon, which if they cause problems are normally to the lean side. Wouldn't be a bad idea to check valve clearances, and also roll the engine over by hand making sure both valves are opening the same distance. The issue could be a sign of a worn cam lobe causing one valve to fully open and stay open long enough to do its cycle. Your issue sounds like incomplete combustion under load.

 

[Eagle1]

Maybe check the jet size, just got a replacement carb for a chinese ATV and the main jet in the new one was just over the half the size of the old jet. Installed old jet in new carb and it runs fine under load, when it would not with smaller jet.

 

[jpilk99]

Thank you all for your help. I went back to the original carb, cleaned it (again), and the machine is running pretty well. I ordered a new (OEM) ignition coil and did clean the fly wheel magnet. Hopefully she stays happy!!! Thanks again