tmorriss 3 #1 Posted September 30, 2022 I have a 1987 312-8. It's been in the family since new. A couple weeks ago, I noticed a slight loss of power when mowing uphill with cutter active. It 'seemed' to go away and the next couple times I mowed, it really wasn't noticeable. Today, as soon as I started it up, I noticed it. And when I put the mower on, the engine bogged and just wasn't reving as it usually did. As soon as I started up a slight incline the tractor had all it could do to keep the mower going and the tractor moving. The tractor has used oil for years, and it does also leak a little somewhere in the cylinder area. It starts right up and idles fine, but if you just leave it sit, idling/running for a period, it seems to start to not run quite right eventually. I haven't done much yet. Compression is about 110 psi. Plug is new this year, but black :( Top of piston is across between very light gray to white. Haven't checked spark yet, but that is next. Then, probably take the carb off and tear it apart. After that, I'm not sure where to go. Appreciate any tips, or if anyone else has had this happen , any info at all. Thx in advance Share this post Link to post Share on other sites
RED-Z06 2,118 #2 Posted October 1, 2022 Black plug could be a bit rich but if its burning oil that is contributing to thr color. Id go 1/4 turn in on the main needle (the top one) and see if there is any change, if not, go back 1/2 turn..if no improvement..1/4 turn in puts you back to 0. Its entirely possible its just worn...needs a refresh, burning oil clogs the ring lands up and affects ring seal 1 Share this post Link to post Share on other sites
953 nut 51,653 #3 Posted October 1, 2022 You could have some blockage in your muffler causing backpressure and not allowing the engine to breath. 2 1 Share this post Link to post Share on other sites
