Gravely g-14

bigreddm · Aug 25, 2018

Got a gravely 14-g single cylinder 14hp Kohler. Runs about half an hour then starts sputtering and backfiring. put a new module/coil and a new fuel pump was installed about 2 months ago. Has a good clean fuel filter and carb is clean inside.also has new air filter and pre cleaner. what could be causing this issue?

T.R.K. · Aug 25, 2018

It could still be fuel delivery. Not necessarily the carburetor. It could also be valve adjustment, not enough clearance.

Dave BN · Aug 26, 2018

Is the gas cap vented? Is the vent clogged? That could cause an eventual gas flow issue.

t1 · Aug 26, 2018

IF you're sure its not a fuel dilivery issue, try removing the blower shroud and other sheet metal, especially around the valve area. Get all of the cooling fins exposed all the way around the engine. I had one do this, and i replaced all of the ignition parts until I tore it down one rainy afternoon and found a wad of old oily grass blocking the cooling fins around the side of the block near the valves. What would happen was it would get hot enough, the exhaust valve would start to stick in its guide, and the engine would back fire and blow fire out of the exhaust and shut down. After a couple minutes, it would fire up again and run fine for a bit, and do it again. After cleaning that out, it would run perfect all day without issue. Gravely's are especially suseptible to this since the engines are mounted down low, and they'll pull all kinds of dirt and debris in through the flywheel when running.

bigreddm · Aug 26, 2018

What r the valves to be set at? By the way thanks for the input.

TomIn · Aug 26, 2018

Intake valve .008 - .010
Exhaust valve .017 - .019

I have heard some complaints that the muffler on a Kohler 14G engine may get "plugged up" and cause the exhaust flow to be restricted. This can overheat the engine and cause the exhaust valve to stick when the engine is extremely hot.

You can find a free downloadable service manual from several sources.

https://www.kohler-engine-parts.opeengines.com/index.php?main_page=document_general_info&products_id=34596

Mule Meat · Aug 26, 2018

Intake = 8 - 10 thousandths
Exhaust = 17 -19 thousandths

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Have you checked the fuel pump to make sure that it is pumping enough fuel?

Steve@Advance · Aug 26, 2018

Replace the plug! Just to say you did...

Fought the same problem on a Kawasaki mower engine.

Many hours and dollars later, a new plug fixed it! LOL

gab · Aug 26, 2018

I have a 14 hsp. Kohler on a Wheel Horse that used to do similar only it took about an hour and a half of mowing to do it. It was a sticking exhaust valve, I just dumped a little Marvel Mystery oil in the gas tank now and then and hasn't done it again in over ten years.

jeffcat · Aug 27, 2018

I have a couple of Gravely walk behinds and another thing I would add. Switch over to a synthetic blend oil. Dino oils can carbon up with the heat in aircooled engines and things will stick. Also a tiny dash of SeaFoam in the oil and a little in the gas will remove a lot of carbon build up. If you change the plug I would HIGHLY recomend buying a NGK Iridium sparkplug. Not cheap but wow do they work great. Almost every small engine I own now has Iridium plugs. Most every time they start faster than you can let go of the key switch.

Gravely g-14

bigreddm

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T.R.K.

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Dave BN

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t1

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bigreddm

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TomIn

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Mule Meat

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Steve@Advance

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gab

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jeffcat

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