possible head gasket issue?

[topgun129]

Hi, I changed my head gasket on my 18 HP Craftsman lawn tractor back in 2017 and since then its been running fine. I do proper maintenance every year on it. (spark plug, oil, air filter etc.)

But a couple of days ago I started it and it ran fine for 35 mins.

But I noticed after I drive the tractor from an incline and then level out on even ground it starts smoking like crazy. Same when I'm in a decline and then level out.

I'm just wondering if its a head gasket issue again? I'm surprised the gasket only lasted 4 years? I'm thinking to remove the plug and seeing if its gotten really black.

Thanks

 

[dougand3]

What's the engine model #?

 

[topgun129]

310000

 

[dougand3]

Briggs 31xxxx do blow the HG between piston and valves. Sounds like the symptoms. Pull your head and see. Check valve clearances, too.

 

[Scrubcadet10]

Start your tractor, get up to operating temp, shut it down and remove the dipstick. If there are wisps of smoke coming out of the tube , most likely a blown head gasket.

 

[StarTech]

Another layman check for these 21,28,31, and 33 series head gaskets is to look in the air filter side of the carburetor. If blown head gasket oil is usually present.

The head does not need to be pull the check for blown head gasket either as the leak down test will reveal this with the rocker cover is removed as air escaping sound will be louder at the push rod galley when compare to the oil fill tube.

Also if you do need a new head gasket use the newer torque spec of 250 in lbs (21 ft-lbs) using three step torque method.

 

[slomo]

Tip on head gasket replacement. Clean the areas where the gasket goes. And clean it again. You might want to clean this area real good. Get it. Think HOSPITAL clean here.

Stay away from metallic scrapers. Use the below link instead.

3M™ Scotch-Brite Roloc Bristle Disc | Aircraft Spruce

3M™ Scotch-Brite Roloc Bristle Disc Brush-like bristle disc removes coarse coatings from the large, open areas of a work piece. Works on right angle tools quickly and easily with little or no pressure.

www.aircraftspruce.com

Degrease the gasket area with foaming window cleaner and clean paper towels. The paper towel will show you if the surface/s are still dirty. Look at your used paper towels for evidence. Don't use brake cleaner as most lazy people will do. You need the scrubbing action to remove ANY contaminants on the aluminum.

Torque the bolts in 3 stages to factory specs.

Lastly you MUST use some spray tack or the head gasket will fail again over time. Read the directions and shake the crap out of the can.







View attachment 56306

 

[topgun129]

here are some photos i took after investigating. i don't see any oil in the air filter (this is an old one from last year so it still dirty). spark plug looks slightly blackened after only apx. 40 mins. of use.

i'm thinking at this point its just better to replace the head gasket again. its probably no more than $15 for all the parts. but i'm surprised it failed so quickly.

 

[slomo]

I'd go for a hotter plug or two.

That black mess could be oil vapors in the air filter. Can't tell from the picture.

slomo

 

[StarTech]

Personally I use the 2" 3M strip disc system here that attached to die grinder and I have choice grits. Either way don't get too agressive as to take off too much metal.