Briggs Valve leak?

[Okie294life]

I’ve got a Briggs intek mower, always smells like gas out the exhaust and the engine makes a ticking noise. It also takes 3-4 pulls to start it. Have had the valves clearanced by a shop same deal? Are these symptoms of leaking valves or should I look elsewhere?

 

[frank_]

the decompressor that jabs the exh valve open maybe ? (ie, idle too slow )

 

[Okie294life]

the decompressor that jabs the exh valve open maybe ? (ie, idle too slow) don’t think that’s it. Have had the valve cover off, and both the valves seem to come up on tdc. Doesn’t seem to have this setup. It pulls easy like it’s got no compression but it doesn’t burn oil so I’m thinking valves.

 

[TBS]

I’ve got a Briggs intek mower, always smells like gas out the exhaust and the engine makes a ticking noise. It also takes 3-4 pulls to start it. Have had the valves clearanced by a shop same deal? Are these symptoms of leaking valves or should I look elsewhere?

The Intek I have has had that gas smell since my grandpa had it, had carburetor rebuilt once but didn't change the smell. The ticking could be spark related. Get a mechanic stethoscope or some rubber hose and you can probably get a good idea of where it is coming from.

 

[cookies]

compression test it before you chase rabbit holes, check the coil to magnet gap and for rust/trash build up. briggs has always had problems with the exhaust valve not sealing, guide/valve stem wear etc. A cylinder leak test using compressed air will expose leaky valves, simple valve lapping may be in order, bent pushrods and worn cam lobes are not uncommon.

 

[joe25DA]

compression test it before you chase rabbit holes, check the coil to magnet gap and for rust/trash build up. briggs has always had problems with the exhaust valve not sealing, guide/valve stem wear etc. A cylinder leak test using compressed air will expose leaky valves, simple valve lapping may be in order, bent pushrods and worn cam lobes are not uncommon.

On the older L Heads I always pull the head off and “stake” the valve seats prevent future headaches from a loose seat at least

 

[gumneck]

I'll go even simpler, Is the valve lash set correct to spec? Hard to start is a symptom of out of spec.

 

[Okie294life]

I'll go even simpler, Is the valve lash set correct to spec? Hard to start is a symptom of out of spec.

Valve lash is okay. I think it’s something else. I checked both valves and properly clearances the rocker arms

 

[joe25DA]

I just went thru something similar. We have a Honda GX 120 on a 150 gal sprayer. Started running ****** last year. Replaced carb, ran well for about a week. Then no start. Re checked carb, fuel lines, filter, checked for spark multiple times, low oil switch. All fine. Pulled valve covers checked valves those were fine, also this is a very low hour machine. Did a cold compression test, 60psi, that’s low. Added oil thru plug hole comp went to 120psi. Finally did a leak down test air and bubbles in crankcase. Carb and exhaust sealed. So it needs to be torn down and rebuilt. It’s now a parts engine

 

[Okie294life]

I just went thru something similar. We have a Honda GX 120 on a 150 gal sprayer. Started running ****** last year. Replaced carb, ran well for about a week. Then no start. Re checked carb, fuel lines, filter, checked for spark multiple times, low oil switch. All fine. Pulled valve covers checked valves those were fine, also this is a very low hour machine. Did a cold compression test, 60psi, that’s low. Added oil thru plug hole comp went to 120psi. Finally did a leak down test air and bubbles in crankcase. Carb and exhaust sealed. So it needs to be torn down and rebuilt. It’s now a parts engine

That sucks. I think I may start by doing a compression test, but just the fact that i smell a lot of gas when it runs leads me to believe it’s the valves, and it runs great otherwise. I’ve had some Hondas engines and a Honda mower at one point. Just never was a huge fan of the 160, they always seemed a little gutless.

 

[medalist]

Easy way to quickly ascertain compression on B&S is by spinning flywheel backwards. This takes Easy Start valve lag out of equation.
Should bounce back freely against the compression smoothly.
This was accomplished far easier on engines without a safety brake.

Valve specs are critical on single cylinder engines. Read the Service. Book for proper instructions.

Good luck.