Rings getting stuck to the piston causing loss of compression is a common problem with this model. It appears that carbon deposits build up in the ring guides causing them to jam in and no longer seal against the cylinder walls.
Just picked one of these blowers up from the dump, wont start which I'm assuming is why it was in the dump lol I pulled the spark arrestor and sure enough those rings are locked into the piston, which some scoring on both the piston and the sleeve. Luckily I'm a pretty handy guy and will be digging into this first thing in the morning. I'll be sure to use extra care when removing those rings and use some brake clean! I have seen some rings online for this piston supposedly. I'm wondering if larger slots can be machined into the piston on a lathe allowing for a thicker ring to be used?
That’s a good idea. It would stop you from needing to tear into it again. I don’t have a lathe so I wasn’t able to try anything like that. One thing I am going to do is sea foam the engine every year to get rid of the carbon deposits that seem to be the culprit
@@adamaustin4865 thanks! I'm gonna give it a try when/if the rings get stuck again, I was able to free them up and it now starts on the 1st or second pull! Great little blower, especially for the price! 😉
I am currently in the same situation as you with the piston rings...have you found anyone that stocks them? I know other Ryobi engines show that you can order the rings for the piston but it all comes down to size and I have not been able to find anyone to take measurements of the rings for me. I do know that the Ryobi 678747003 piston rings are too big in diameter but are correct for thickness. ....so don't buy those!
Update, after massive research and a couple of ring purchases, I believe I found the correct rings for your/my Ryobi bp42....part number 690161006. I just received them today, install them on the Piston which seems to fit perfectly. I will be reinstalling the engine and components this weekend and I will stop back in tell you how it worked.
I went ahead and ordered those rings and they indeed did work out for me I just threw it together quickly but it attempted to fire and I need to reassemble the rest of it
