2007 Toro Recycler Easy Start 190cc B&S hard starting

[kingjames1]

Found this mower for free several years ago. It wouldn't start. Put in a new carb and it started right up. Ran it for a couple years but last year it had a hard time starting.

Yesterday I ran a leak down test and it said it was only 70%. I could also hear air coming out of the exhaust.

I took off the head and the gasket looks okay. But there appears to be little specks of carbon around the exhaust seat. The piston head doesn't seem to have an excess of carbon. There is a little side to side play in the valves. There is no scoring on the cylinder wall.

So a couple questions:

Can carbon cause the compression leak?

Can these valve seats be ground and reseated?

Is a little side to side play in the valves normal?

Thanks for your help.

 

[Bertrrr]

You can lap the valves with a little lapping compound, How does the compression stack up other than leak down ?
Carbon can score the cylinders and is very abrasive , side to side indicates worn valve guides and can be a cause for smoke / low compression lack of power etc.

 

[ILENGINE]

Don't worry about the side to side movement in the valve. some movement is normal, and without the proper valve guide gauges would be hard to tell if excessive or not. Lap the valves back in and reset the valve clearance, install a new head gasket and go back to mowing.

 

[kingjames1]

Don't worry about the side to side movement in the valve. some movement is normal, and without the proper valve guide gauges would be hard to tell if excessive or not. Lap the valves back in and reset the valve clearance, install a new head gasket and go back to mowing.

Ok I'll give that a go. Thank you.

 

[kingjames1]

Don't worry about the side to side movement in the valve. some movement is normal, and without the proper valve guide gauges would be hard to tell if excessive or not. Lap the valves back in and reset the valve clearance, install a new head gasket and go back to mowing.

Compression was about 33 lbs. Exhaust valve was more snug than the intake.

 

[ILENGINE]

Compression was about 33 lbs. Exhaust valve was more snug than the intake.

With compression release the compression reading in all but meaningless. Have worked on brand new Briggs engines with 30 psi out of the box. Worked on a generator a few years back that read 95% or 5% bypass so everything was sealing properly. Compression reading was 5 psi. That one had a clogged spark arrester screen in the muffler preventing it from running due to exhaust backpressure.

 

[kingjames1]

Ok. Thanks.

 

[SeniorCitizen]

I've seen 3 engines in my life that failed after the valves were lapped . All cylinders on a ford failed simultaneously after about 1,000 miles with broken rings from groove and ring wear . This lap job was done at a ford dealership . Second was a buddy that lapped valves of 1 cylinder on a V8 ford . That cyl. failed after approx.
120 miles . Third was a 1 cylinder mower
that made1 mow and wouldn't start after that . A work buddy ask me why and i knew he had worked on it . The first question i ask him was --- did you lapp the valves ? My answer was --check compression -- sure nuff it was low .

Now, why . All of that lapping compound must be thoroughly cleaned from the valves and seats before it is started .

When i was in diesel school many years ago there was a special detergent for cleaning that with a stiff brush after all was wiped with a shop towel .

 

[kingjames1]

Ok but I'm guessing the low compression was from the exhaust valve having carbon on it.

I don't know, I'm no mechanic but I'm not afraid to wrench either.

My brother and I rebuilt my 383 Roadrunner when I was 18. Lapped (He called it grinding.) the valves and all and never had a problem. But that was long time ago.

I ran the compression test first on the mower but then read on one of these posts the leak down test is better. Air coming out of the exhaust is what led me to take the head off and see what was going on.

These forums are great. You learn a lot of stuff on them.

 

[Tiger Small Engine]

I've seen 3 engines in my life that failed after the valves were lapped . All cylinders on a ford failed simultaneously after about 1,000 miles with broken rings from groove and ring wear . This lap job was done at a ford dealership . Second was a buddy that lapped valves of 1 cylinder on a V8 ford . That cyl. failed after approx.
120 miles . Third was a 1 cylinder mower
that made1 mow and wouldn't start after that . A work buddy ask me why and i knew he had worked on it . The first question i ask him was --- did you lapp the valves ? My answer was --check compression -- sure nuff it was low .

Now, why . All of that lapping compound must be thoroughly cleaned from the valves and seats before it is started .

When i was in diesel school many years ago there was a special detergent for cleaning that with a stiff brush after all was wiped with a shop towel .

Anyone who knows how to properly lap and set valve clearance , should know you must thoroughly clean all the lapping compound after. It doesn’t get any more basic.