Good night, I love it when a plan comes togather.
Posted July 25, 2011 - 09:17 PM
So, I ordered a carb kit and took my time cleaning and rebuilding it. I even took the time to wire brush all the paint off by hand so it looked brand new. (ever notice that is when things go wrong?) Well, I put it back on and it was really giving me fits! Hardly running, flooding, and back firing. I took the carb off and went through it agian and gave it a second try. This time on the second pull, I could tell she lost compression!
The crank seemed connected to the piston because it was smooth and quiet, so I pulled the head. I then found the exhaust valve did not move! After pulling the breather cover, I found my problem was just the keeper washer that failed, but it damaged the valve. This set up had a plain washer with something like a keyhole that locked onto the valve stem. A pretty poor design which Briggs seems to of changed. I did end up with a new valve and keeper from s Jacks, but I ordered the ones that I had, and they sent the new design! I still needed the special washer for the newer "car style" keepers and washer. I did not buy that from Jacks, as I was not sure what they would send... I did find a NOS on e-bay though.
After spending an hour or two making a tool to compress the springs and hand lapping the valves, I was able to get it ready to go. Although, the head was missing! I looked for almost an hour before I remembered it was soaking in the parts washer to loosen the gasket! Once it was all together, I crossed my fingers, choked her and gave it a tug. She fires right up and rand great! I was very worried that the valve was not the problem, and I would still have carb issues.
Dang, I get long winded! I have had this dang tiller in my shop for months trying to find parts. It seems that Briggs discontinued the valves for this motor (1981 8hp horz.) It feels good to once again bring it back to life! This is the third major come back for it. Once when I got it from my dad and it had sat with water in the carb for almost 10 years, then again when I tossed a rod through the block, and again after a broken valve....
I just figured I would share... though didn't plan to write a novel!
Posted July 25, 2011 - 09:45 PM
Posted July 25, 2011 - 10:16 PM
Happy Ends are great.
Glad you got it going! I love happy endings.
Posted July 26, 2011 - 06:36 AM
Posted July 26, 2011 - 07:53 AM
Posted July 26, 2011 - 08:04 AM
Glad you got it figured out. I don't mind reading long posts, just helps to understand the issue you were having. I hope you looked over the intake valve while you were in there. Good luck with it.
Thanks all, Kenny, yes I did pop the valve spring off the intake valve to take a look. What is odd is that they used the "car style" keeper on the intake, but not the exhaust. While I had that side apart I did re-lap and ground the stems to adjust the lash on both sides.
Posted July 26, 2011 - 08:19 AM
Posted July 26, 2011 - 08:57 AM
Posted July 26, 2011 - 09:30 AM
Very nice to hear you got it running good again. I don't know why but it almost seems like out of all the engine brands Briggs has the most trouble in the valve area. Maybe it is just coincidence in the past year and I am totally off on my comment.
Yea, this poor motor has been through the ringer! The valve keeper design was just dumb on this motor. I mean, it looked more like the washer that retains a brake shoe, than a valve! Just a simple washer with a key-hole, no retainers at all! Yet, they used a normal keeper on the intake. I mean, really??
I just fine-tuned the carb, and ran it in the garden... She runs just great, and will walk through the yard in high gear at an idle. That is the way she should run for me! This is one of the better Briggs motors, and seeing that is 30 years old, I can't really fault it much. This is the Industrial/Commercial version with roller bearings and a cast iron sleeve in the block.
Posted July 26, 2011 - 04:45 PM
Posted July 26, 2011 - 04:56 PM
Posted July 26, 2011 - 06:38 PM
Posted July 26, 2011 - 09:35 PM
Here is the tool I made for compressing the valve springs. This pair of clamps had a broken spring was was very beat up, plus... I have plenty of them! It's great to have a lathe in the shop for times like this! I even turned down the pin that is a hammer fit for the valve side press block.
Posted July 26, 2011 - 10:39 PM