I have 2 quarts of the Kawasaki 10w40 so ill use that to begin with then may switch to 15w50 as i think i read kawasaki changed to preferring the 50wt. Because the bore is still round and square i went with a 3in brush research ball hone to remove the mirror finish but not remove cylinder wall thickness as everything i have checked so far is still nice and in factory spec.
Kawasaki fr691v smokes badly
- Thread starter joegreen
- Start date
Pistons look great and the cylinders too. I don't think they need real honing. Some people just scrub them quickly with Scotch Bright dish sponge and wash them well with water and degreaser.
The oil is also very good for the break-in. Cannot wait to see it running.
Great job!
The oil is also very good for the break-in. Cannot wait to see it running.
Great job!
After re-reading this thread, I think that many of us may have been jumping to the wrong conclusion after the first post. It could be a case of correlation does not equal causation.
Looking at the smooth bores and massive ring gaps compared to the comparatively low engine hours, it may have ingested a bunch of dust. The huge nest may have come after the 3 year sit that it experienced due to a belt coming off. This would also account for the smoking. As for the fouled plug - I didn't see where you said that you checked for spark on both cylinders? You're definitely going to want to do that prior to starting.
Looking at the smooth bores and massive ring gaps compared to the comparatively low engine hours, it may have ingested a bunch of dust. The huge nest may have come after the 3 year sit that it experienced due to a belt coming off. This would also account for the smoking. As for the fouled plug - I didn't see where you said that you checked for spark on both cylinders? You're definitely going to want to do that prior to starting.
Good point about jumping to conclusions. The nest could have definitely come after sitting. Also this engine is known for the rocker arm bolt to come loose causing the rocker to come off the pushrod. The machine was parked because it stopped moving. The only thing wrong was the belt was old and dry rotted and chuncks were missing. This tells me he basically bought it and probably did very little maintenance on it to just junk it without even exploring the cause of the issue. It did have a newer air filter and oil filter and spark plugs but they were that off brand from amazon that comes with those torch plugs or whatever so again pointing to least amount spent on the mower.
Ahhhhhhhhhh... That makes some sense then! I bought a supposed low hour Briggs 23hp twin for a mower project and when I got it back I thought that I'd been duped as for some stupid reason I didn't realize that it seemed to be in a factory styrofoam skid. First thing is that I pulled the plugs - they were some no name Chinese plugs and was met with basically the same sight as your plug and I thought for sure it was a bad motor. After all, why else would it be in a factory skid? Now I'm thinking that it was a problem child and it got warrantied out and this guy managed to get a hold of it. Well in my case I came out alright. I checked the leak down and it was 5% in both cyls so I put in new Champion plugs, cleaned the carb and fired it up on the skid with no exhaust. It ran fine, so I went ahead and installed it on the mower - it's on its second season now and it runs like a champ and burns minimal oil!
Honed both cylinders out. I used a 22.5 degree cut piece of paper to measure the crosshatch angle to get the proper 45 degree. It is close enough. Ball hone worked great. Cylinders look good. Cylinder two has a few lines at the very top of the bore i noticed. No big deal.
Looks good.
Did you use a 240 grit? Was it a 3 1/4 hone ?
It was a brush research bc30024. 3inch hone 240 grit. I called the company and that’s what they recommended. It fit the bore great. Not too snug but not loose.
Did you start the machine?
May we see video or pictures?
I will definitely update the post once its all back together. Right now i have everything mostly cleaned up motor wise. I am waiting on a few parts from cub cadet. A couple seals for the carburetor, new oil pump plate and some updated metal oil passage tubes between the case halves. It will probably be a few weeks before its done.
I need some help with the piston ring orientation. I have the factory service manual which I am inclined to believe but I am getting some conflicting information or maybe I am not interpreting the manual correctly. I will paste the instructions from the manual below. All of my confusion comes from the second piston ring. For starters both the top ring and the second ring are factory Kawasaki parts and are laser etched 1R on the top ring and 2R on the second ring. The top ring has a blue paint mark on it and the second ring has a pink paint mark on it. The manual calls the second ring to have a white paint mark. I figure white and light pink are close enough and there is only one paint mark on there anyway. The first thing they want is the white paint mark on the right side of the ring gap. I am going to assume this is looking directly at the side of the piston. Because if i look at the piston from the top down vs the side the white paint mark can either be on the left or right side of the ring gap. Now the second ring is the only ring with a prominent feature and that is a step on one side of the ring. The manual states that they want the step facing upwards. They even have a diagram showing the direction of the step facing upwards. Here are my issues. From random reading online it seems common place for the laser etched writing to face the top of the piston. This is not stated in the manual so it doesn't hold much weight but it is something. Now if i am looking at the side of the piston with the stepped edge of the piston ring facing towards the top of the piston the laser etched 2R is facing towards the bottom of the piston and the white paint mark is on the left side of the ring gap. From what i have read online again about the stepped piston ring design its some type of oil scraper and they would want that step facing towards the bottom of the piston to scrape oil back into the sump. If i place the stepped edge facing the bottom of the piston then the white mark and the laser etching would be in the correct orientation. But I have a hard time believing that they misdrew the picture vs had a typo about which side of the ring gap the white mark needs to be. So does this stepped edge face the top or bottom of the piston?
Its called a Napier style piston ring and it looks like its supposed to face downwards. https://www.enginebuildermag.com/2025/09/how-to-identify-piston-rings-and-proper-orientation/
Thanks , thats it! 32:37
I reread the instructions and i noticed under the install second ring portion it has the instructions for “replacing with new one” and “reassembling the ring in use”. If i follow the white mark instructions for replacing with a new one then the notched edge faces the bottom of the piston. If i follow the ring in use instructions then the notched edge faces up.
I can get pictures when i get home
