KyBlue 655 #1 Posted May 12, 2013 Okay folks ... I just picked this up off Ebay. The guy I bought it from, bought it at auction and knew zip about it. He did say it smoked a lil at startup, which isn't a huge deal. I had planned on having it rebuilt this winter however, upon doing a Pre use tune up ... I found one of the cylinders to be dead. The plug was soaked in fuel and looked as though it had never fired. I changed the plugs anyway, and the new set does the same thing. It's running on the Front Cylinder just as it should, but the back one isn't firing. Looking down into the cylinder I can see the valves open close. I checked for spark, it's a crappy orange ... I'm wondering if I need to pull the motor for a complete O/H or If the Coil Module is messing up or if It's something more...severe. Good Oil Pressure No Odd Noises Plug is Wet (says there is some compression to draw in the fuel) I don't want to throw a 140 dollar part at the New tractor if it's NOT going to help... just looking for some advice. Share this post Link to post Share on other sites
pfrederi 18,371 #2 Posted May 13, 2013 (edited) Is the spark on number one noticeably stronger??? Could be a bad plug wire Edited May 13, 2013 by pfrederi Share this post Link to post Share on other sites
KyBlue 655 #3 Posted May 15, 2013 Is the spark on number one noticeably stronger??? Could be a bad plug wire Yes, it's a very weak orange color. The downside is the Coil Module is made into the plug wires, can't change anything. I have checked the condition at the plug, and the length of the cable back to the coil module itself. All is good, clean, free of any visible damage. Of course w/o being able to access the other end, I can't test resistance. On a side note, I called a somewhat local repair shop (was recommended to me) their rough quote was 1600 with boring the jugs and turning the crank ... good thing I was sitting down! Share this post Link to post Share on other sites
bitten 134 #4 Posted May 15, 2013 Check all electrical first. I would try a new coil first before a rebuild. Share this post Link to post Share on other sites
MarkPalmer 81 #5 Posted May 15, 2013 Remove the spark plug and verify if you can feel suction and compression when cranking the engine. Even though the plug might be wet, in many of these cases I have come across with Magnum and KT twins the rod for the non-firing cylinder is broken. Yes, amazingly these engines will run on one cylinder, and can even sound good while doing so. I've even seen a few where the rod went right through the block, and the engine still ran on the one cylinder -Mark- Share this post Link to post Share on other sites
pfrederi 18,371 #6 Posted May 15, 2013 (edited) I don't have a twin cylinder magnum book handy. But there are tests for the module primary and secondary. For singles it is primary 1.0 to 1.3 ohms secondary 7,900 to 10,850) Also have you checked the air gap (Module to flywheel???) Found my magnum twin book Only test the secondary should be 22-42,000 ohms the air gap should be .008 to .012 Edited May 15, 2013 by pfrederi 1 Share this post Link to post Share on other sites
KyBlue 655 #7 Posted May 17, 2013 I'm going to pull the head sometime this week and see what exactly is going on. I don't see the rod as being broken but ... weirder things have happened. It shouldn't be a major ordeal to overhaul it, and besides its got 1700 hours on it, so It's not like rebuilding it is a bad thing. Will check the module and the gap. thanks for the info Paul! Share this post Link to post Share on other sites
wallfish 17,569 #8 Posted May 17, 2013 I have a spare coil from a M18 I can send you. The issue was the lamination is separated on the front side from sitting out in the weather which caused the engine to run rough once it warmed up but it started and ran good until warm. I did a few things at the same time to cure the problem so I'm not 100% positive this coil was the problem. I wonder if you can use it to change the coil onto your laminate piece. There's one wire connection attached to the laminate but other than that it appears the coil will come off. If you want it, just shoot me a PM with your address and I'll send it to you. No charge, just pay it forward Share this post Link to post Share on other sites
KyBlue 655 #9 Posted May 21, 2013 It's official ... The Rod is either Broken, or maybe just came apart ... I pulled the head today, and the rings and valves are good, there is some schmutz on the intake valve but nothing that cant be cleaned up.... Im going to pull it apart farther and see why the piston isn't moving. I'm hoping that nothing else is hurt ... Service manual's should be here wednesday or thursday. Share this post Link to post Share on other sites
KyBlue 655 #10 Posted May 21, 2013 Now to clean the workbench off and Pull the motor. Just fuel line and control cables to go ... Share this post Link to post Share on other sites
MarkPalmer 81 #11 Posted May 21, 2013 The rod has been snapped in half on the ones I have worked on, it was mostly on KT17 series 1 engines but it can happen to any of the opposed twins. The cause is usually the rod bearing seizing to the crankpin from lack of oil. -Mark- Share this post Link to post Share on other sites
KyBlue 655 #12 Posted May 21, 2013 why the lack of oil? design flaw or crappy oil change habbits? let's hope i don't need a new crank. Share this post Link to post Share on other sites
MarkPalmer 81 #13 Posted May 21, 2013 why the lack of oil? design flaw or crappy oil change habbits? let's hope i don't need a new crank. It's hard to know exactly why, even when you take it apart. Even though the Magnums and later series 2 KT's had full pressure lube this can still happen. Some causes can be oil allowed to get excessively dirty, very heavy continuous engine loading, use on extremely steep slopes, or plain old wear from high useage hours where it's time had come. Most of the time, if the crankpins aren't worn more than .010 overall or aren't more than .005 out of round the crank can be machined for undersize rods. There are also used cranks available in conditions that can be anyone's guess on Fleabay. -Mark- Share this post Link to post Share on other sites
pfrederi 18,371 #14 Posted May 21, 2013 (edited) Take a very close look at the case of the motor. I have worked with 2 KT17s that broke rods...in both cases the motor case was damaged, one was obvious...big hole in the case, the other was a couple of small cracks. The case is cast aluminum not steel/iron and breaks easily. as to cause I would lean more to operator neglect than to any design flaw in the KT series 2 and the Magnums (which were KT Series 2 with a different ignition system) Edited May 21, 2013 by pfrederi Share this post Link to post Share on other sites
KyBlue 655 #15 Posted May 21, 2013 i'll be sure and check it for cracks. have the powder and dye system ... used commonly on cylinder heads. thanks for the heads up Share this post Link to post Share on other sites
KyBlue 655 #16 Posted May 22, 2013 Dead Cylinder The Cylinder it was running on ... Now I can only sit on it and make Engine Noises! LOL Motor is out, Everything has come off easily, The bad Cylinder head was only finger tight, the motor plate bolts were all loose, the Drive belt was cracked ... so I just cut it to get it off... Share this post Link to post Share on other sites
KyBlue 655 #17 Posted May 26, 2013 -Mark- Called it. Rod's broken. Crank is Saveable or so it appears. Its scratched but nothing huge or very deep. Dye test on the case half shows zero cracks Outside, I'll clean and check the inside once i split the case, Cylinder Jug has to be replaced it took the brunt of the impact. Pics Share this post Link to post Share on other sites
