Briggs sticking valve.

[Sean McGillicuddy]

I have a stuck valve in my v twin Briggs engine.
What would cause this ? Carbon build up?
Any tips to get unstuck?
I found this when trying to adjust the 4 valves.
Thought are welcomed!

 

[sportbikerider78]

If you are engine savy enough to pop the valve cover and adjust the valves..pop the head off and have a look'see.

 

[Krogoski]

Had a John Deere with a Briggs 22hp vtwin. The intake valves would get stuck. I finally, after a number of years dealing with it, determined that it was old/bad gas that caused it. Seemed that every spring it would start to muck up around the third tank fill. Fuel was stored over winter with sta-bil. It would do it again after the summer slow growth season. Fuel stored for a few weeks, again treated. I got the procedure down to spraying SeaFoam deep creep down the carb while it tried to run. A few spritz's and she'd wake up. I have since changed to Pri-G for treatment with no further issues. I also no longer store more than 5 gallons of treated fuel at a time and have a local station that sells ethanol free fuel. Just my experiences. In my case it was varnish in the guides, and the penetrating oil knocked it out.

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[Sean McGillicuddy]

Krogoski
My thought exactly!
I also will do the see foam when I get some time!
Thanks

 

[sportbikerider78]

Are we talking sticky valve causing engine pinging or a seized valve?

 

[Sean McGillicuddy]

Are we talking sticky valve causing engine pinging or a seized valve?

One of the four is not moving .... So I don,t know what's wrong.
I was looking for a way to move it with out using a hammer.
Spring is complety compressed.

 

[sportbikerider78]

You need to get inside the head. Pop the spark plug out and see what the piston position is. You might be able to see something.

 

[Krogoski]

One thing we used to do on an old Ferguson to20, which I likewise did on my sticky briggs twin the first time, is pop the valve cover and pull the plug. Rotate the engine to bdc for that cylinder, spray down the valve and guide with penetrating oil, and start tapping the valve stem with a plastic hammer. Back and forth penetrating oil and tapping until they'd pop loose. Wouldn't take long and whatever crud was holding the valve open would be gone. Use your discretion, for me it's a Briggs not a Bugatti. I've never encountered a bent valve in a Briggs. Pushrods, absolutely, but not a valve.

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[Sean McGillicuddy]

After spraying the valve with see foam and let it sit for a couple days , I tapped it with a small hammer and POP
We are good to go!
Spent some more time with the engine running and spraying see foam in the intake .. the engine runs like a charm!

 

[Jazzberry]

Sea Foam is awesome stuff. Used to decrarb my outboards with it. The gunk that comes out after an overnight soak will amaze you.

 

[wock]

seafoam is great, one of the few products that works.

another honorable mention to putting some marvel mystery oil in your oil change, might help.

 

[Krogoski]

MMO is good stuff too. In my experience however, the valve stem deposits are more on the combustion chamber side than the rocker/valve cover side. I dont believe that enough oil actually makes it onto and down the stem to prevent sticktion in the bore due to fuel related combustion chamber side deposits. I buy Rotella T6 in bulk so everything gets it. Motorcycles, jetskis, boats, tractors, trucks, any miscellaneous power equipment. I imagine that if T6 allowed a valve to stick in my equipment, MMO isnt going to change the equation. I do however use MMO in my JD GT with the Kohler CV that has hydraulic tappets. Those tappets stick a couple times a year and MMO opens them right up. That mower has over 1500 hours and is due for retirement, but a little MMO and she just keeps going, now if I could get the fuel related issues fixed I'd consider keeping the machine, but thats a different story.

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[wock]

you could try switching to a high mileage, semi-synthetic for the JD.... being slightly "slicker" might be all you need.

sea foam can actually be mixed in the gas to keep deposits down. or occasionally misting water in the carb helps a little as it "steams" them off somewhat. I have heard kerosene can have the same benefit as well. you might even be able to try a 50/1 mix sprayed in, running.

I mean I know the gas is crap, but any idea why you are seeing so many deposits? most gas nowadays has detergents.

what are the fuel related issues?

I usually just use the basic crap stens 5/30 or 10/30 depending on my mood and the season. I have debated going synthetic for the fleet, but we never keep anything longer than 3 years and the oil gets changed pretty regularly depending on use.

 

[Ashful]

Will probably stick again, after a few runs. Easy solution, install new valve guide and lap in a new valve. Entire job can be done in one evening, with the right tools, which are cheap.


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[Krogoski]

Rotella T6 is a full synthetic 5w-40, and in all equipment I run it in I get no sludge or deposit formation with excellent wear characteristics. I assume that the issues with the tappets in the Kohler are age related (15 years old) and for the time being MMO takes care of the issues. I'm certain that most folks cant hear, don't know or simply don't care when the tappets start to make noise. When I do notice the slight increase in valve train noise, add a bit of MMO and the noise vanishes in a few minutes of running.

When we had our JD with the Briggs Twin, as stated above, an intake valve would stick open a couple times a year and seafoam sprayed down the carb while running would knock it loose. I don't know exactly why old gas would cause the issues I experienced, but it did and the fix was pretty easy. While I owned that machine, the only concrete variable I could settle on was Gas treated with Sta-bil, left over winter or over the summer a few weeks, would religiously cause a valve to stick. Very occasionally it would do it in the mowing season, but I had always purchased fuel just prior to the issue, so it must have been bad gas or the station was selling old gas. I'm sure treating the fuel with Seafoam prior to use might mitigate the issue, but my solution was adopting Pri-G as a fuel stabilizer after which I never had another sticky valve caused by MY storage of fuel.

I had the sticky valve problem on my JD Briggs Twin from day one. The first time it stuck it had roughly 25 hours on it and by the end, I could set my watch by it. I'm not sure if there was a problem with MY machine in particular, or just the quality of the fuel here in Southern Indiana. The fact is, I could have replaced the guide but a little SeaFoam a couple times a year made it run like it was new. I wasn't going to be bothered with the job, especially since the root cause turned out to be fuel quality related, could not be remedied and replacing the guide would likely have not changed my scenario. This is my experience only and I hope my experiences with a similar issue on a similar product helps save the OP time in the future.

I sold the JD with the Briggs twin several years ago, as I hated the deck, with ~500 hours on it. Yesterday I spoke with the work mate I sold it to, with full disclosure of the sticky valve, and he mentioned to me that the issue has visited him many times over the years and the Seafoam trick has worked every time. Who knows how long it will keep doing it, but it's 12 years old now, still running strong. It just has some character.