93' 312-8. Help me get it going.

[Rugith 6]

I got this tractor last fall. She mowed pretty good the last couple mowings of the year and did good the first one of this year. I thought this year all I would need to do is get it cleaned up, change the fluids, and maybe new blades. Well, the last time I mowed with it, I ran the tank dry, filled it up, and haven't been able to start it since. Now excuse me for being so mechanical challenged but I swear I'm a fast learner with guidance.  So I checked the gas bulb thing that appears to have a filter in it. Although there is a small amount of gas in it, it's by no means full. I'm wandering if it's vapor locked or something? Any thoughts would be great. Also you can see in the pictures that the clutch is rigged up with a bungie cord. If anyone could give me idea what to fix there that would be great. Hopefully it is as simple as swapping a spring 😁

[oliver2-44 10,783]

First off  lot of friendly help here.  Your 312-8 is a great tractor.

I restored a 1985 version for my son when he bought his first house. 

An engine needs Fuel, Air and Spark to run, so........ 

 

FUEL -Since running out of gas seemed to cause a change lets start with the fuel system. 

Your gas tank is located under the rear fender seat area, and is barely above the level of the carburetor when full.  When you run out of gas you can suck any crud that might be in the bottom of the tank into the carburetor, the fuel pump, the in-line filter or the screen that is inside the bottom of the tank connected to the tank fuel shut off valve. 

The easiest place to start is to verify gas is getting to the carb. On the front of the engine, under the carb, disconnect the gas hose the goes between the fuel pump and the carb.  Crank the engine over and see if gas is pumping out of the fuel pump.  If you have gas there, it might be time to clean the carb.  But next check...

 

SPARK-The next easiest thing to do is verify you have spark.  for safety, wipe up any gas that may be on or around the engine/floor from testing the gas flow.  Pull the spark plug, and with the spark plug wire connected and the threaded part of the plug held against the top of the engine (to ground it) have someone crank the engine and watch if you see spark at the bottom end of the plug.  (PS take a picture and show us what the end of it looks like ie clean or dirty, to help us help you.  

 

AIR-The next easiest thing to do is make sure all the parts of your engine are working to move air in and exhaust out.  Remove the engine air filter and have some one crank the tractor over several revolutions, while covering the exhaust with your hand.  The engine should suck enough air in and force it out the exhaust for you to feel air pumping out the exhaust.   

 

If you have SPARK and AIR, lets go back to FUEL.  if you don't have gas spurting out of the fuel pump, work backwards toward the tank disconnecting the line at each connection until you get gas flow. (be ready to close the gas shutoff valve located at the bottom of the tank when you get flow). If you have flow before the fuel pump it means your pump needs to be cleaned or replaced.  If you get to the shut off valve and still don't have flow, it means the screen inside the tank is plugged and needs to be replaced.  if you had fuel coming out the carb side of the fuel pump, let us know and we can help you clean the carb. 

 

Make those checks and let us know what you find.

 

Once you get it back running we can help you do a through maintenance on it.

 

    

 

[953 nut 60,385]

One important thing Jim didn't mention is the type of gas used in any lawn and garden engine. Today's "Ethanol Enhanced" crap will kill a small engine. The deposits will plug up a fuel system and it will destroy rubber components. Use this site to locate a station in your area that sells real gas, https://www.pure-gas.org/.

[Rugith 6]

6 hours ago, oliver2-44 said:

First off  lot of friendly help here.  Your 312-8 is a great tractor.

I restored a 1985 version for my son when he bought his first house. 

An engine needs Fuel, Air and Spark to run, so........ 

 

FUEL -Since running out of gas seemed to cause a change lets start with the fuel system. 

Your gas tank is located under the rear fender seat area, and is barely above the level of the carburetor when full.  When you run out of gas you can suck any crud that might be in the bottom of the tank into the carburetor, the fuel pump, the in-line filter or the screen that is inside the bottom of the tank connected to the tank fuel shut off valve. 

The easiest place to start is to verify gas is getting to the carb. On the front of the engine, under the carb, disconnect the gas hose the goes between the fuel pump and the carb.  Crank the engine over and see if gas is pumping out of the fuel pump.  If you have gas there, it might be time to clean the carb.  But next check...

 

SPARK-The next easiest thing to do is verify you have spark.  for safety, wipe up any gas that may be on or around the engine/floor from testing the gas flow.  Pull the spark plug, and with the spark plug wire connected and the threaded part of the plug held against the top of the engine (to ground it) have someone crank the engine and watch if you see spark at the bottom end of the plug.  (PS take a picture and show us what the end of it looks like ie clean or dirty, to help us help you.  

 

AIR-The next easiest thing to do is make sure all the parts of your engine are working to move air in and exhaust out.  Remove the engine air filter and have some one crank the tractor over several revolutions, while covering the exhaust with your hand.  The engine should suck enough air in and force it out the exhaust for you to feel air pumping out the exhaust.   

 

If you have SPARK and AIR, lets go back to FUEL.  if you don't have gas spurting out of the fuel pump, work backwards toward the tank disconnecting the line at each connection until you get gas flow. (be ready to close the gas shutoff valve located at the bottom of the tank when you get flow). If you have flow before the fuel pump it means your pump needs to be cleaned or replaced.  If you get to the shut off valve and still don't have flow, it means the screen inside the tank is plugged and needs to be replaced.  if you had fuel coming out the carb side of the fuel pump, let us know and we can help you clean the carb. 

 

Make those checks and let us know what you find.

 

Once you get it back running we can help you do a through maintenance on it.

 

    

 

This is amazingly thorough. I should have time within the next few days to try all this and I will update the thread. And thank you 😀

[peter lena 9,316]

that clutch issue is probably a broken return spring, trace the linkage lever back to the trunion swivel point . along side of transaxel. go to hardware store and pick up a similar size and tension spring . that fuel issue was probably growing for a long time before you got the horse. agree with above on fuel, engine state of tune issues . remember you are recovering neglect, probably won,t  get it all the first time, stay with it , you will get it , pete

[Tuneup 1,452]

Rugith took great time and care in giving you the basics. If you're the hurried type, you might want to just get a can of carb cleaner like Gumout, remove the air filter, give it a 1 second shot into the carb throat and hit the starter. If nothing, try once more. If still nothing, start on the spark paragraph. If it does kick to life, move to the fuel paragraph. That would be my approach. If it cranks slowly, make sure there is a good charge on the battery first or give it a jump with a good battery. Just don't leave jumper cables connected longer than absolutely necessary. Always fun to see them puff to life on Gumout...

[peter lena 9,316]

i have used this with great results, https://www.walmart.com/ip/Sea-Foam-SS14-Cleaner-and-Lube/41772464?wmlspartner=wlpa&selectedSellerId=282&adid=22222222227029362560&wl0=&wl1=g&wl2=c&wl3=62907108729&wl4=aud-566049426705:pla-99429869529&wl5=9003291&wl6=&wl7=&wl8=&wl9=pla&wl10=111838817&wl11=online&wl12=41772464&veh=sem&gclid=Cj0KCQjwgezoBRDNARIsAGzEfe74hxpGLwpi2RmJHWjRIsCzF3jI4yMghTWfxJDzaL7EwDhYagQqd_4aAqC5EALw_wcB. after it starts and warms up , i use my hand on carb intake to suck the carb out while running , jmoo , pete

[ohiofarmer 3,379]

Before going through all the what ifs on the fuel system, what I would do is disconnect the fuel line back at you tank and add some line and a slave tank maybe five feet off the ground. My slave tank has a shut off valve as well for testing carbs against leaking

What you want to do is get the air out of the fuel lines and prime the fuel pump. Once primed, the tractor may run normally the rest of the season . Even if it doesn't fix the problem, you still have a good diagnostic tool.

[953 nut 60,385]

I respectfully disagree.    If you don't take the time to correct the problems that caused this event you will have the same problems all over again. And as Murphy's Law tells us it WILL happen at the most inconvenient time and at the worst possible place.

You have some deferred maintenance issues that need correction and if done properly they will eliminate future disappointment.

[RandyLittrell 3,906]

I have a 310-8 very much like yours. First time I run it dry, I had the same problem. When you run them dry, you get that last bit of crap thats been hanging out in the tank. You might as well get new lines and filter, and clean the tank. You may need to clean the carb too. I did on mine. 

 

 

 

 

Randy

[ohiofarmer 3,379]

I guess I will defer to the experts then.  It just saves me time to at least partially prime those fuel hoses because fuel is not compressible as is air. I have a high lift machine that runs a big 4 cyl . Wisconsin that I have to blow air in the gas cap opening in order to get the electric pump to prime. Works fine for the rest of the day for ten years now. I have also seen Briggs style fuel pumps replace the expensive type of pump to good result

 

  I have two 8 HP in tractors ready to run. one of them has fuel pump issues. so I will assume a good fuel pump will self prime with air ad there probably is not a situation where they will pump primed fuel.  They do look to be repairable, however.

  

 Agree wit Randy about letting the tank run dry. Just better not to do it. Finally Casey's gas and general sore came to ohio, and we can get ethanol free gas. so that also helps Anywaay... Good luck with your project.!

[gwest_ca-(File Mod) 11,528]

One thing I have learned is the fuel hoses need to be soft and pliable when they are installed on the nipple. A hard hose will allow the fuel pump to suck air at the nipple connection but the fuel will not leak out at the same location making a leak hard to detect. Since air is compressible once it is mixed with the fuel the small fuel pump stroke is not large enough to overcome the air. The vacuum created by the pump just expands the air volume at each pulse with nothing left to pull the fuel along.

These mechanical pumps are quite capable. I had a fuel cap vent plug up on a 312-8. The pump collapsed the tank and pulled the cap through the rear fender pan before the engine starved for fuel and quit. Had to pull the pan to get the cap off and blow the tank back up to full size.

 

Garry

[clueless 3,263]

These tank in the back single cylinders can be a bear to start when they've sat for awhile and even worse when run dry. The old blowing in the tank fill hole my help get things moving, just don't do it with more than a half of tank . I would empty the tank clean it and check the on off valve, then replace the fuel lines with new ones and a new filter, all petty easy and cheap. Then fill the tank about 1/4 full and spin it over, you need a fully charged battery, that may get it flowing. When I replaced the fuel lines on my 312-8 I put a outboard motor fuel squeeze ball between the line under the seat, again cheap fix. It can sit for months, lift the seat give it a couple of good squeezes, she fires right up .

[Racinbob 11,991]

As far as your clutch problem, \that model uses a gas spring located on the right side. It is attached to the idler arm and some point on the frame. It doesn't have the spring on the left side. Get a #108035 return spring and install it on the left. Remove the gas spring completely and you'll be good to go.

[Rugith 6]

Well, I finally found some time to do some diagnosing and i found out i don't have any fuel leaving the tank. I'm going to drop it this weekend and get it all cleaned out. 

Thanks for all the great replies.

[AHenry014 127]

New tank petcock and grommets are very cheap and good insurance to ensure you have good flow.  I install new fuel line on any tractor i get for good measure.  I too have had the same issue as you when i ran the tractor dry.  What i did was pull the fuel line from the inlet side of the fuel pump and drop the line below fuel tank level to draw the fuel up the line.  Once its there, reconnect to the pump and you should be good to go.  Sometimes the pump has a hard time self priming.