Garden Tractor Forums banner
1 - 9 of 9 Posts

·
New Member
Joined
·
31 Posts
Discussion Starter · #1 ·
We have an 812 (K301 Kohler) that has been so reliable for so many years that it comes as a shock if it has any problems. A couple of weeks ago it started losing some power while mowing and acted exactly like it was running out of gas. Checked the gas and it had fuel; replaced the inline fuel filter but no help. Thought maybe the gas was contaminated but draining some off the bottom showed it looked fine. So a week goes by and I try the mower again and it starts right up and runs fine. I had just finished mowing the yard, about 1 acre and I am driving it back to the shed and it starts doing the same thing after running fine for about 45 min. In fact, using the choke I was able to keep it running enough to get it back to the shed. I am wondering if a marginal fuel pump could act up when it gets warm? I thought maybe vapor lock but could see fuel in the filter. Any suggestions would be appreciated.
 

·
Mark J.
Joined
·
2,350 Posts
Have you checked the fuel line hose to see if there is any obstruction in it? Maybe the hose is collapsing inside due to age or degradation. Maybe the carb has some sediments or corrosion in the bottom of the fuel bowl that could have been sucked up into the high speed circuit. I used only ethanol free gas in my small engines to prevent that from happening. Hope this helps. Good luck.
 

·
Fixer of Broken junk
Joined
·
5,120 Posts
Drop the bowl and put a cup or soda bottle under the carb and crank it bit and see what the fuel flow looks like. Soda bottle or milk jug with the top cut off works good. I keep a couple different sized clear plastic bottles in my little shop just for that. Milk jug is pretty cool because you can leave the handle on it lol.


Those things do have like 5 foot of fuel line lol. The inner lining will deteriorate and goes soft over time. After a while it looks and feels like that super sticky black Windshield Adhesive. Was going to say tar but what it turns into is thicker and stickier. You can usually feel it with your fingers if it goes bad. It will be nice and plyable on the outside and have a harder but squishy center.

Could have got a bug in the fuel tank as well. Just fixed a mower that ran fine for about 20-30 minutes and started surging really bad. It had one of those nasty little yellow jackets in the fuel tank. Must have been in there for a while because it was petrified and turned solid yellow. It was floating around in the bottom and would stop up the petcock then float up just off of the bottom when you shut the tractor off and let it sit for a bit. That was in a newer Cub Cadet with the large plastic tank under the fenders. Couldn't see down into the bottom of the tank but I knew there was something floating around in it by the way it acted.

A bit of water or Ethanol Gel in your carb will make them act like that.

I've had Kohlers get junk buildup in behind the float needle seat. It abruptly goes from a 1/4" fuel line down to a small hole rite there so if there is any dirt or debris getting through it will either end up rite there or in the float bowl. I had 1 that I put a new filter on and some how a small piece of grass got in and was stopping up the needle seat. Have no idea how that got in there. Luckily those seats are removable. Makes them easy to clean.

Being an old Kohler when is the last time you checked the head bolts and head gasket? They should occasionally be checked. The head gaskets with the Fire ring can be reused. I wouldn't reuse the ones that don't have the fire ring because they could be blown out between the layers. I actually keep a few good used head gaskets hanging in the shed. New ones with the fire ring are getting harder to find. Alot of manufactures are switching over to those Junk Carbon Composite head gaskets probibly because they are alot cheaper since they are just punched out of a large rolls of material.
 

·
Registered
Joined
·
2 Posts
We have an 812 (K301 Kohler) that has been so reliable for so many years that it comes as a shock if it has any problems. A couple of weeks ago it started losing some power while mowing and acted exactly like it was running out of gas. Checked the gas and it had fuel; replaced the inline fuel filter but no help. Thought maybe the gas was contaminated but draining some off the bottom showed it looked fine. So a week goes by and I try the mower again and it starts right up and runs fine. I had just finished mowing the yard, about 1 acre and I am driving it back to the shed and it starts doing the same thing after running fine for about 45 min. In fact, using the choke I was able to keep it running enough to get it back to the shed. I am wondering if a marginal fuel pump could act up when it gets warm? I thought maybe vapor lock but could see fuel in the filter. Any suggestions would be appreciated.

Hi, I suspect the carburetor is at fault here. It might be gummed up from moisture that has gotten into the bowl. You can try putting the carb in the oven set on propane or natural gas to dry it out, or you could try running some carb cleaner through it. You could also try a squirt of carb cleaner down the fuel line to try and clean it. Your local lawn mower repair shop can probably help you with this.
 

·
New Member
Joined
·
31 Posts
Discussion Starter · #6 ·
Thanks for the responses. I had to move a nonrunning car I am restoring that had no steering and used the Gravely to tow it. It would run for a max of about 10 min at a time as I would readjust the steering for the next move. It did that with no problems, starting easy, and running smooth. It still seems like a fuel delivery problem when it gets warm. I did test the fuel pump but only with the engine cold. I just don't see how a carburetor could be the problem and then it recovers after the mower sets overnight and does this repeatedly. My next move is to run it until the problem happens and then see if it is getting fuel.

Just to add, the fuel line is mostly steel except for a short section by the engine. I have replaced that rubber fuel line but it still acts the same.
 

·
Fixer of Broken junk
Joined
·
5,120 Posts
Are you running a 12v coil with internal resistor or a regular 12v coil with a Ballast resistor? Check the temperature of your coil. They run warm but they should not get too Hot to touch. If it's getting hot then it is about to fail. Once they cool down they will work until they get hot again. I had 2 of those cheap $9 internal resistor coils off of amazon fail this year. Both of them boiled there oil out. 1 was almost 2 years old and the other was only 2 months old.


Might have a mouse nest under the blower housing that is causing the engine to overheat. Gas will boil in a kohler float bowl. Easiest way to find out if it is vapor locking from heat? Look in the gas tank with a bright flashlight rite after it starts running like crap and look for bubbles coming from the petcock area at the bottom of the carb. Mice and chipmunks love Kohler engines because there is alot of room for a nest under the blower housing and only 1 way in and out rite between the valves and cylinder.

I've seen dozens of engines packed with everything and anything that you can think of. Had 1 that was completely packed with Acorns. Fella that I worked on it for thought it was locked up or blown up. That Pink Insulation is the worst to clean up. They pack it in really tight and pee all over it which makes dirt and stuff stick to it like a magnet. It will quickly cause an engine to over heat.
 

·
New Member
Joined
·
31 Posts
Discussion Starter · #8 · (Edited)
Are you running a 12v coil with internal resistor or a regular 12v coil with a Ballast resistor? Check the temperature of your coil. They run warm but they should not get too Hot to touch. If it's getting hot then it is about to fail. Once they cool down they will work until they get hot again. ...

...I've seen dozens of engines packed with everything and anything that you can think of. Had 1 that was completely packed with Acorns. Fella that I worked on it for thought it was locked up or blown up. That Pink Insulation is the worst to clean up. They pack it in really tight and pee all over it which makes dirt and stuff stick to it like a magnet. It will quickly cause an engine to over heat.
Thank you for the response. I too have had coil and rodent issues when I was living in PA with a 5665 Professional that I left at the garden a lot. The worst was ants built a nest in it once! :)

It never loses spark and if you give it choke, it will keep running after this problem starts. Even after it has stopped, it still has spark so it does not indicate a coil problem. Things are warmer in Florida but it does not seem any hotter than normal. I am still leaning toward a fuel pump problem that gets worse with heat. Next time it stops, I will check the fuel flow.

I will post when I get to the bottom of the problem. Again, thank you for all the responses.
 

·
New Member
Joined
·
31 Posts
Discussion Starter · #9 ·
As promised, I am following up on the thread. I thought the problem may be the fuel pump so I just put one of those plastic pumps in to try that. They cost less than $10 and I can rebuild the old one if needed. Anyway I have used the Gravely at least 5 times with the new pump and it runs now with no problems. If something else happens I will let you all know. As for now, it looks like problem solved. Thanks for all of the responses.
 
1 - 9 of 9 Posts
Top