Briggs vtwin intek 20hp running on one cylinder

[davidsh]

As the title says, I've and John Deere La110 with a v twin Briggs & stratton engine. I think its running on one cylinder. I should mention I'm not that experienced with engines.

Symptoms:

• Low on power - bogs down when you engage the manual blade lever. After it warms up its less likely to bog down.
• Thirsty on fuel - a lot more so than it was last season.
• Noisy - although there's a crack in the exhaust so this could account for the noise.
• If I disconnect the spark plug on the right hand cylinder, she wont start and flames/pops from the connected side. With left disconnected and right connected she fires up fine.
• Valve cover on right hand side is hot to touch if you run from cold for a few mins. Left hand side is only barely warm.

What I've tried so far:

• Replaced both spark plugs.
• Replaced both ignition coils (I wasn't getting any reading off ohm meter from old ones)
• Removed the valve cover on the right hand cylinder. Push rods are straight and rockers look to have correct amount of travel.

Someone suggested that it might be blockage in the fuel jets in the carburetor but I'm slow to go at that myself as it looks like a bit of a handful taking it apart. Just wondering if anyone out there has any other ideas what it could be before I give up?

Any help is much appreciated.

Thanks
David

 

[Bertrrr]

Pull your plugs and run a compression test , hot valve cover on one side might indicate a burnt exhaust valve
How was it running before this issue ? A little history on the machine will go a long way in trouble shooting what's goin on now. If you don't have a compression tester stick your finger into the spark plug hole and get an idea of one cylinder compared to the other.

 

[Fish]

Look at the valves on the other side.

 

[davidsh]

So I looked at the valves on the other side and they look ok too (to the best of my knowledge).

I don't have a compression tester but I tried as you suggested Bertrrr and I don't feel any push or pull when I turn the fly wheel. On either spark plug hole. I'm assuming this should be noticeable enough? I'll try to pick up a tester during the week to be sure. There's a squeak out of the carburetor when I do turn the fly wheel - almost like air coming out of a balloon. Not sure if this is normal or an indication that a gasket is gone somewhere?

As for as history goes, I don't have much. I got it cheap two years ago and have just used it to maintain a half acre lawn area at home. It ran fine last season, but noticeably down on power and thirsty this season. I've a 6.5hp Toro push mower and it tackles cutting better than it. Also I'm thinking it was an engine swap, as from what I've read I think the John Deere LA110 came with a 19.5hp single cylinder engine.

Thanks for the replies - much appreciated.

 

[Bertrrr]

You should notice some sort of compression coming from the spark plug hole but might have to almost close off the whole opening only letting a tiny bit of blow by. Were the plugs clean when you removed them ? Burnt looking or dry and gray ? Black looking plugs indicate no fire, gray and clean show there was good spark, Did you by chance run it low on oil? Rings may be stuck , compression tester will tell the tell.

 

[TiIngot]

Timing might be off due to the flywheel key shearing. $2.13 key solved my problem. But it further cost over $250 more because previous owner drove it overheating the cylinder head which pushed out the valve guides bending the pushrods. New cylinder head, new pushrods, new gaskets needed because $2.13 key sheared.

 

[Tiger Small Engine]

Yep, John Deere LA110 series usually comes with single cylinder around 19 horsepower.

Check valve cover for: Model, Type, and Code.
First two digits on code are year of manufacture.

Timing might be off due to the flywheel key shearing. $2.13 key solved my problem. But it further cost over $250 more because previous owner drove it overheating the cylinder head which pushed out the valve guides bending the pushrods. New cylinder head, new pushrods, new gaskets needed because $2.13 key sheared.

 

[davidsh]

Sorry about the delay in getting back on this - work has been taking up any free time to look at it further.

Bertrrr: Plugs do look black/carbonised - and as I mentioned I've only replaced them recently. I haven't run her low on oil myself but I can't say the same about past history.

I got a compression tester and ran a test twice on both (this is from cold). 105psi on the good side and only 25psi on the suspect side. I've read compression tests aren't that accurate on a vtwin due to some auto pressure release aid - but I'm guessing that the difference is still fairly indicative of the issue.

Tilngot : I took a video of the valve action on suspect side. I'll try attaching a link. Seems to me like there is movement/wobble in the cylinder valve rod/rocker after the exhaust cycle (but again my untrained eye). At around 10 and 13 seconds in. Maybe this is normal though?

Thanks again

 

[davidsh]

Link to video

VEED - Vtwin.mp4

Make stunning videos with a single click. Cut, trim, crop, add subtitles and more. Online, no account needed. Try it now, free. VEED

www.veed.io

 

[Fish]

The one on the bottom looks a little tight. What are the valve clearances?