Kawasaki fr691v smokes badly

[jhellwig]

The first picture makes it look like the piston is sloppy in the cylinder. If the piston can move around a lot in the cylinder that is where your smoke is coming from because the rings are worn out also.

Run it till it dies. I wouldn't put much money into it.

 

[john_pifer]

thanks for the reminder to check and make sure the cooling fins on my cylinders are clear.

 

[joegreen]

The first picture makes it look like the piston is sloppy in the cylinder. If the piston can move around a lot in the cylinder that is where your smoke is coming from because the rings are worn out also.

Run it till it dies. I wouldn't put much money into it.

I would love to run it till it dies but it smokes so bad i can’t comfortably mow with it. Ill be fumigated. I dont mind rebuilding it but would prefer not too. I really like the machine

 

[Lawnman23]

I would love to run it till it dies but it smokes so bad i can’t comfortably mow with it. Ill be fumigated. I dont mind rebuilding it but would prefer not too. I really like the machine

As a Hail Mary, you could try a bottle of Ring Seal along with some Valvoline HM MaxLife 20w-50 and give it some runtime. Both available at Walmart.

 

[The_Eric]

The rings are cooked, get a set and gently hone the cylinder and you'll be much better off.

 

[joegreen]

Im thinking maybe the cylinder got hot enough that the oil control ring spring lost tension and is allowing oil to get sucked into the cylinder. I will have to measure the bore either with my t gauges at various points or i may be able to use a bore micrometer from my job.

 

[ripcord]

The cylinder could be significantly warped and out of round, too.

 

[kballowe]

Im thinking maybe the cylinder got hot enough that the oil control ring spring lost tension and is allowing oil to get sucked into the cylinder. I will have to measure the bore either with my t gauges at various points or i may be able to use a bore micrometer from my job.

I agree.

 

[The_Eric]

Im thinking maybe the cylinder got hot enough that the oil control ring spring lost tension and is allowing oil to get sucked into the cylinder. I will have to measure the bore either with my t gauges at various points or i may be able to use a bore micrometer from my job.

Probably the second ring.

 

[joegreen]

I opened the dipstick as an easy check and holy crankcase pressure batman. All the compression is going past the rings. I think i could have used it as an air compressor.

 

[asker123]

How much you paid for this? Hope not much.

 

[Fordiesel69]

I have saved many 2 cycle and 4 cycle engines with rings and a quick hone. The cylinder looks nice, you should be able to get away with just that.

 

[joegreen]

How much you paid for this? Hope not much.

Free

 

[The_Eric]

I opened the dipstick as an easy check and holy crankcase pressure batman. All the compression is going past the rings. I think i could have used it as an air compressor.

There will definitely be a lot going in inside the crankcase. If you pulled the dipstick while it was running then fully expect to get a face full of oil, even on a healthy engine. The crank, rods, pistons and cam will be throwing oil EVERYWHERE! Plus the pistons will displace a fair bit of the crankcase atmosphere as they go back and forth.

 

[joegreen]

There will definitely be a lot going in inside the crankcase. If you pulled the dipstick while it was running then fully expect to get a face full of oil, even on a healthy engine. The crank, rods, pistons and cam will be throwing oil EVERYWHERE! Plus the pistons will displace a fair bit of the crankcase atmosphere as they go back and forth.

Oh yeah I didn’t think of the displacement from the back of the piston motion. I guess that’s why the dipstick screws on with an o ring.

 

[joegreen]

Update on the engine situation. I tore the whole thing down today. I did not find any smoking gun as to the oil consumption issue. I checked both cylinders for roundness with a t gauge and a micrometer. Good news is both cylinders are fine. They are round and of the same diameter top to bottom. The cylinder walls are quite shiny. The piston rings on both cylinders were nice and clean and quite springy. I was hoping to find an issue there but i didnt notice anything. I am not sure what to do. The only thing i can think is to hone it and put new rings into it. Also you can see how carboned and oily the brand new spark plug got after running for maybe 1hr

 

[ripcord]

What is the valve stem to guide clearance like?

 

[joegreen]

What is the valve stem to guide clearance like?

Im not sure. When i cleaned the cylinder head and lapped the valve seats the valve stems felt like they slid tight but smooth into the valve guides. The motor only has 350 hours on it and is very clean inside.

 

[spasm3]

Put just the old rings back in the cylinder and square them with the piston. Then measure the ring end gap. Do this at the top of the bore as will as the bottom to see if they is any taper.

EDIT: I see you mic checked it.

I'd still put the rings in and check the gap to see what is vs stock. Put the new rings in and check the gaps on them as well.

Check the piston to bore clearance.

 

[The_Eric]

How does the free, uncompressed ring gap on the second ring for the cyl in question compare to the other side?