fourwheels0 191 #1 Posted August 13, 2015 ok here's the story.1986 314-8 classic with the 14hp magnum with 566 hrs. it was running fine and was shut off for a while and went back to start it and it turned over normally a couple times then just spun like no compression. would a valve maybe gotten stuck open? or connecting rod let loose?.haven't tore into it yet just wondering. Share this post Link to post Share on other sites
Rob R 951 #2 Posted August 13, 2015 Me thinks you broke the ole connecting rod..... easy to determine just take the plug out and see if the piston is moving, if you cant see it use a straw in the plug hole. 1 Share this post Link to post Share on other sites
tunahead72 2,340 #3 Posted August 13, 2015 The engine actually spins? So, not like the starter is just not engaging the flywheel? 1 Share this post Link to post Share on other sites
slammer302 2,154 #4 Posted August 13, 2015 I had this happen to a 310-8 it was a broken ring and piston Sent from my XT1080 using Tapatalk Share this post Link to post Share on other sites
fourwheels0 191 #5 Posted August 13, 2015 ya i'm thinking it's the rod. just weird the way it happened. I have to go pick it up and look into it. Share this post Link to post Share on other sites
Shynon 7,435 #6 Posted August 13, 2015 Stuck valve, it was running when you shut it off, I have never heard of a rod breaking on startup. Just my Share this post Link to post Share on other sites
Dirtdog524 61 #7 Posted August 16, 2015 I agree with Shynon. Look at the valves before you go any further into the engine. I suspect you will find your problem. Share this post Link to post Share on other sites
fourwheels0 191 #8 Posted August 17, 2015 i'm gonna pull the head in the morning. hopefully I find good news and it's just a stuck valve. Share this post Link to post Share on other sites
fourwheels0 191 #9 Posted August 17, 2015 ok I was off on the year. it's a 1993 314-8. Share this post Link to post Share on other sites
fourwheels0 191 #10 Posted August 17, 2015 yup it was a stuck valve. sprayed some pb blaster on it and she popped back down. top and stem looked clean with no carbon buildup. what would cause it to stick? and what can I do to keep it from sticking again?. Share this post Link to post Share on other sites
rick 215 #11 Posted August 18, 2015 Carbon deposits will cause a stuck valve. The carbon build up could be in the valve guide, and not on the stem. Varnish from degraded fuel can also cause the problem. You can add Marvel Mystery Oil or Seafoam to the fuel. Always use fresh fuel, of the proper octane, and from a major oil company. Share this post Link to post Share on other sites
fourwheels0 191 #12 Posted August 18, 2015 it's got good fresh gas now and I put in some lucas fuel system cleaner that is supposed to clean the valves,stems,head ect.it's running good now but i'll run it for a tank or two and she how it goes.I could see the previous owner really didn't maintain it like he should have. Share this post Link to post Share on other sites
Shynon 7,435 #13 Posted August 19, 2015 If you haven't already done so I would also change the oil. Share this post Link to post Share on other sites