What octane fuel for Briggs and Stratton Intek 24hp intek v-twin for Husqvarna Lawn tractor?

Messages
670
Location
va
My tractor is surging at idle either because I used E-15 in it or because I used a bungee cord around the throttle lever to hold the side discharge open to mow tall wet grass in a hurry. The throttle cable is not making it to the snow icon anymore (makes it but won't stay there so I suspect it is that).

...but the experience scared me and I won't be doing either of these things any more....

So the manual says minimum of 89 octane. What would you do? I am not sure what my local gas station has...options are likely 87, 89, 91, and 93.

Any advice on octane?

Thanks.
 
Messages
13,073
Location
North Carolina
I don't think surging is going to be fixed with octane. Octane simply prevents preignition. I would check your throttle linkage, especially the springs. If there is no problem there, you have an internal fuel delivery problem with the carb. Air leak or something in the jets. You may have to remove and clean every orifice of the carb with a stylet.

Run the octane the manual suggests, if its not available, the next highest.
 
Last edited:

dx92beater

Thread starter
Messages
670
Location
va
I don't think surging is going to be fixed with octane. Octane simply prevents preignition. I would check your throttle linkage, especially the springs. If there is no problem there, you have an internal fuel delivery problem with the carb. Air leak or something in the jets. You may have to remove and clean every orifice of the carb with a stylet.

Run the octane the manual suggests, if its not available, the next highest.

Thanks for your suggestion. I concur. I just wanted to get the octane part correct moving forward. Thanks for the advice.
 

JTK

Messages
13,429
Location
Buffalo, NY
Regular grade E10 will be fine for you provided you keep it in sealed storage containers and don't let it sit in the mower's tank unused for months at a time.

Like said above, the more fool proof method is buy fuel from a store that sells zero ethanol. The valero station down the street from my house sells E0 "Recreational fuel". I forget if it's 89 or 91oct, but it's a good $0.75/gal more expensive than E10.

If your engine is oscillating up/down with RPMs, you likely have a partially plugged jet in the carb. I just replace the carb and hang on to the OEM one.
 
Messages
3,238
Location
USA
The "snow icon" I guess means choke, for starting in cold weather. It isn't supposed to be run there, it's only for starting. There should also be turtle and rabbit, set it on rabbit for mowing.

Surging with no load is often because the low speed jet(s) in the carb are clogged. This will not hurt anything if you don't want to work on it.
 
Messages
1,187
Location
Pacific Northwest
Surging is usually caused by a lean condition. Not enough gas for the amount of air coming in. Most times I've seen this on a rider it's because of a restricted fuel filter. Other causes include water in the fuel, vacuum leaks, and dirty passages in the carb. You don't want to run the engine too long or hard this way as it will run hot and eventually burn pistons, valves, or blow head gaskets.

When you replace the fuel filter, make sure to use one meant for lawn tractors and not one meant for automobiles which are too restrictive. Also, catch some fuel in a clean container while you are changing the filter and let it sit for a while to see if any water settles at the bottom. If you see any water droplets, drain the tank and put in fresh.
 
Messages
11,359
Location
Florida, Cape Coral
I have the 22 HP version B&S 2cyl INTEK engine. 87 Octane 100% of its like of 175 hours. I did try 91 once and no difference I suspect that the throttle cable is mistrusted at the carburetor and the throttle lever demonstrates that. .
I concur wirhg ripcord above, with regard to the surging. Ed
 
Check your air filter to make sure its clean. Remove it and give a few shot of spray time carburetor cleaner. It wouldn't hurt to put a bit of bottled gas treatment or or fuel injector cleaner in the gas tank. If that doesn't help you might have small chunk of something in your carb. To get it out, pull the carb, unscrew the bowl nut and have a look. Make sure you pay attention to the order of the gaskets when dissembling. Maybe some our small engine guys can give advice. :)
 
Messages
13,073
Location
North Carolina
One thing i forgot to add. Change your fuel lines. I've had them look fine on the outside, and disintegrate on the inside, plugging jets with bits of trash from the line.
 
Messages
2,353
Location
Southwest Virginia
I also get some surging in my power washer B&S 190 engine with the choke wide open. Closing down the choke a bit smooths it out, but I don't think you have that option on your lawn tractor (I have the same mower & engine).
 
Messages
929
Location
AR
I have had a 21hp V-Twin B&S Intek since 2003.....the first thing I did on a recommendation of a small engine mechanic - was to get rid of the puny little fuel filter and replace it with a autoparts store big one - that has been on there since.....no problems ever - but was told it was a weak point. 87 - 91 octane has never seemed to make any difference....I use fuel stabilizer though....and need to check the valves soon....almost 400hours now.
 
Messages
349
Location
Iowa
My tractor is surging at idle either because I used E-15 in it or because I used a bungee cord around the throttle lever to hold the side discharge open to mow tall wet grass in a hurry. The throttle cable is not making it to the snow icon anymore (makes it but won't stay there so I suspect it is that).

...but the experience scared me and I won't be doing either of these things any more....

So the manual says minimum of 89 octane. What would you do? I am not sure what my local gas station has...options are likely 87, 89, 91, and 93.

Any advice on octane?

Thanks.


Give it some carb cleaner and go with E0 from now on.
 
Messages
113
Location
Washington
I have B&S intek motor in craftsman. Got it used with blown head gasket. After rebuild I used nothing but 92 premium gas. The only thing I add to it, is a little MMO (ration from MMO bottle) and stabilizer. Starts with one crank and runs smooth every time.
 
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