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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

What's the engine model #?

310000

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

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.

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.

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.


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

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.

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

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.

any brand gasket and spark plug you recommend?

topgun129 said:

any brand gasket and spark plug you recommend?

Click to expand...

Briggs and Stratton
and NGK or Champion.

StarTech said:

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.

Click to expand...

3M Rolocs are made in grades not grits. Just saying....

slomo

topgun129 said:

any brand gasket and spark plug you recommend?

Click to expand...

Depends on your engine. Look at you engine manual. Don't think you can go wrong with Champion or NGK.

OEM head gasket would be all I would entertain. Spray it with high tack gasket sealant too. Block sand with 1,000 to 3,000 grit paper with a large block that covers the entire bore area with LIGHT pressure. Let the paper do all the work. Clean slash degrease it prior to installing the gasket. Don't run your fingers across the gasket surfaces. Fingers have oils and acids that you are putting back on the metal. You want a zero residue clean degreased surface.

slomo

I like using the cheap fingernail dressing boards (like they do manicures with) that you get at the dollar stores to dress the deck and head gasket surfaces - a 10 pack is only a couple bucks. They are basically 1/2"w x 6"l sanding boards, and sometimes you can find them with different grits on each side. They are much easier to keep flat than using the 2" abrasive or polishing discs, and leave a slightly roughened surface for the head gasket to bite into.

I think your problem is the driving on an incline.Depending on which way the tractor is leaning it will give the CC breather pick-up access to the engine oil which will then get sucked into the engine and gives you the problem that you describe.Figure out which way not to incline to prevent this and if you have to drive on a slanted surface make sure you do so towards the safe side.

spray both sides of the head gasket with high temp copper gasket sealer:

I have never used anything on a head gasket. get yourself a good scotch-brite pad. You want fine grit. The problem with spray tacks is that sometimes they can get bubbled and cause the gasket not to fit flush. If you are going to use something use a good coppercoat. I have used them on the John Deere ag tractors and that helps to seal the head

GentlemanFahmah said:

spray both sides of the head gasket with high temp copper gasket sealer:

https://www.autozone.com/sealants-glues-adhesives-and-tape/sealant/permatex-copper-high-temperature-spray-a-gasket-sealant-9-oz/520940_0_0

Click to expand...

I've never used the copper no tack version. You would think the copper flavor would have higher heat properties. The spray tack and the copper are rated at the same temps. Wonder what that is about?

I know the hi tack spray is perfect for these troublesome Intek head gaskets. If you put a new gasket on and don't spray it, you will be replacing it in a few years.

slomo

so i opened up the head and here are some photos. i noticed the gasket is in ok shape. i dont see any break in it between the piston and galley where the push rods come thru. but i do see the piston head has a ton of carbon on it. the cylinder area itself is smooth.

i looked at the oil dipstick and noticed it is kind of high (red arrow), but i will say i've never found this to be accurate in all the years. i did the oil change on it a few weeks back and swear putting in 56 ounces like the manual suggests. i attached a photo of the oil i used as well.

any suggestions? i'm not sure what the culprit could be now.

thanks!

here are a few more photos if it helps

Smooth bore says it all
Don't see that very often
Usual suspect is bad filtering of air and most common on FR kawasaki engines because the elbow just does not seal properly unless you are very careful when you replace the air filter.
Bagging on ZTR's accelerates the problem because of all of the very fine dust that gets passed through the bags ends up being sucked into the engine.
Fuel thinned oil is the other big culprit .

@bertsmobile1 - just to confirm, you are suggesting the air filter housing is letting some dirt get thru which is causing this? just wondering what the best resolution is for this. since i opened up the area i cleaned the head area and will install a new gasket

Yes
I often find dust stuck to the fumey residue inside the air filter housing where the breather enters
Sure sign that the air filter is leaking somewhere
Plastic manifolds warp usually from being done up too tight and almost no one replaces the gaskets or O rings when they service the carbs.
My parts supplier confirms this case they always ask what am I doing with them ? Having them with lunch ? as I use 3 to 4 times as many as any other customer .

@bertsmobile1 - i'll go ahead and change both the O ring and carb gasket. i assume you are referring to the blue and red arrows?

Yes
And don't overtighten the mounting studs
Finger tight = 1/4 turn is generally enough to compress the rubber O rign
I use 1/4" thumb drive to prevent me committing the same crime.
Their is another O ring between the manifold & the head which is also prone to get hard & leak.
At $ 1 a hit false economy not to replace all of them.

update - i ran the tractor for 1 hour without issues on mostly flat ground.

but unfortunately the issue re-occured (oil burning), but noticed it occurs near the same area where it occurred before on my lawn. this area is on a slight decline where the engine is pointed downwards. could it be possible there is too much oil in the engine? another idea that i thought of was maybe the valve cover leaks a small amount of oil due to the decline and that drops on the hot muffler?

The sump on these engines is about the same size as a dinner plate and about 1.5" deep
When the engine is tilted forward the oil level gets to be higher than the bottom of the cylinder
When an engine is new it can handle the extra oil .
However the older they get the less capacity they have to tollerate the piston sloshing around in a cylinder full of oil .

makes sense @bertsmobile1. any possible fix for this or maybe time to retire the machine?

A couple of options
1) rering, not too expensive
2) ignore it till you get request for mosquito repelling
3) go one grade heavier oil
4) try synthetic oil

All depends upon what the rest of the mower is like.
Not a good time to buy new gear right now as most factories are Covid affected so out puts are down.

yes actually i was thinking about using thicker oil. what do you recommend to use? 10w-30 synthetic? or something thicker?

don't recommend any particular oil
Synthetics will not fix any problem and in an engine not designed for synthetic oil they are a waste of money
Next if your engine is worn then a strait 30 or 40 or even Harley oil 30W 70 might keep things running a tad longer .