cmosu 0 #1 Posted May 13, 2014 Hey guys. I've been a lurker here for a few weeks but this is my first post. Seems like a great site. My grandma has a 1986 310-8 she bought new. Last year she mistakenly put diesel in it instead of gas. She took it to a friend that does mower repairs on the side and when she got it back it still doesn't run right at high rpms. I told her I would take a look at it but haven't had a chance to really tear into it yet. I was wondering where you guys would start. From what I could tell all he did was drain the tank and put a new fuel line and filter from the tank to the pump. The line from the pump to the carb is original. Also the choke cable is froze. I can choke it by hand and get it started. It runs OK at idle but wants to choke out when you give it more throttle. I'm hoping I'll just have to clean up the carb and reset it but wanted to hear any ideas you might have. Thanks! Sent from my SPH-L720 using Tapatalk Share this post Link to post Share on other sites
SethL1984 38 #2 Posted May 13, 2014 ! I'd take the fuel pump and carb off and clean them both, as well as put a new plug in. Replace the fuel line you mentioned was original too. Share this post Link to post Share on other sites
Fordiesel69 235 #3 Posted May 13, 2014 (edited) Putting diesel in a gas engine is harmless to the fuel system. Going the other way will make short work of a diesel injection system...... So if the choke is off, and assuming the air filter off, open the throtlle to full on your cable. When the governor arm opens up and the engine sounds like it is overfueling (black smoke) begin adjusting the main jet clockwise until the engine runs perfect. Once you get it running perfect, most manuals have you turn the jet in until it runs rough, then back out (counter clockwise) until it runs rough again, and then go right in the middle for you final adjustment. This always works great for me. If during operation it needs another fine ajustment, then I will consider it. On the idle mixture screw, when the engine is at idle, and you open the throttle full very quickly, the engine should not die down and then pick up. That would indicate you need to turn the mixure screw counter clockwise until it accelerates smooth. If you open the throttle quick and the engine accelerated but you get a puff of black at anytime during this transition, then you need to turn the mixture screw clockwise to lean it out. The air filter element will get destroyed if diesel gets on it. It is bascially an oil and will block the paper from flowing air. Edited May 13, 2014 by Fordiesel69 4 Share this post Link to post Share on other sites
Digger 66 3,477 #4 Posted May 13, 2014 Good read there ^ Welcome to the OP . Share this post Link to post Share on other sites
cmosu 0 #5 Posted May 13, 2014 Thanks for the info on adjusting the carb. I will try that before I pull the carb apart. Hopefully I can get to it this weekend and it only needs adjusted. I'm afraid they stopped up the carb while messing with the fuel lines. Sent from my SPH-L720 using Tapatalk Share this post Link to post Share on other sites
Fordiesel69 235 #6 Posted May 14, 2014 Keep in mind that the fuel shutoff valve has an integral filter. Therfore an in line filter only adds to the trouble. The carbs will tolerate some dirt, and it is not the end of the world if they need to be cleaned. With it running rich as you say, I believe an adjustment is all you need. However it would not hurt to clean it, just set the bowel o-ring aside or when you spray with carb cleaner it will grow in diameter big time & you will be very mad....... 1 Share this post Link to post Share on other sites
cmosu 0 #7 Posted May 19, 2014 This weekend i cleaned the screen on the fuel shutoff in the tank, removed the in line fuel filter, checked to make sure the fuel pump wasn't stopped up, freed up the choke cable and cleaned up the carb as much as i could without taking it off the motor. Also cleaned and regapped the spark plug. None of it made any difference. I still can't get it to run properly at high rpms. I also tried running it without the gas cap to make sure that vent wasn't clogged. Where should i go from here? Sent from my SPH-L720 using Tapatalk Share this post Link to post Share on other sites
Fordiesel69 235 #8 Posted May 19, 2014 Start by posting a video. We can hear the problem and be able to advise you better. Share this post Link to post Share on other sites
cmosu 0 #9 Posted February 7, 2015 Sorry to resurrect an old thread. I finally had a chance to mess with this motor today. I noticed the wire from the condenser to the coil was broken so I fixed that and now it is running fine. If that wire was about to break or weak last time I messed with it would that have caused my symptoms? Share this post Link to post Share on other sites
can whlvr 991 #10 Posted February 7, 2015 good to find an easy fix Share this post Link to post Share on other sites
Theroundhousernr 589 #11 Posted February 7, 2015 Sorry to resurrect an old thread. I finally had a chance to mess with this motor today. I noticed the wire from the condenser to the coil was broken so I fixed that and now it is running fine. If that wire was about to break or weak last time I messed with it would that have caused my symptoms? Condenser failure is one of those strange things that gets over looked and leads to people fiddling with the carb and fuel. I always replace condenser and points together. They rarely go bad but for 3 dollars, its worth the peace of mind. Common signs of bad condenser are - points dirty/ pitted ( can see a yellow/green large spark from the points when cover is off - week spark at the plug - missing at higher RPM'S/ but will tend to idle fine Looks like you found the problem. And if it was just a wire it could have fell off after the guy worked on it for her. Good catch though. Now just need a choke cable... Share this post Link to post Share on other sites
cmosu 0 #12 Posted February 7, 2015 Condenser failure is one of those strange things that gets over looked and leads to people fiddling with the carb and fuel. I always replace condenser and points together. They rarely go bad but for 3 dollars, its worth the peace of mind. Common signs of bad condenser are - points dirty/ pitted ( can see a yellow/green large spark from the points when cover is off - week spark at the plug - missing at higher RPM'S/ but will tend to idle fine Looks like you found the problem. And if it was just a wire it could have fell off after the guy worked on it for her. Good catch though. Now just need a choke cable... I'd soaked the cable in pb blaster last time I worked on it and freed it up. It was froze again today though. She okd replacing it today along with the fuel petcock and some minor maintenance items. Share this post Link to post Share on other sites
