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Charlieson

ac 416s running hot

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Charlieson
I have an Allis Chalmers in the family that started running hot toward's the end of last year (K341 Kohler I think). It will actually quit running, usually after a couple of pops and backfires. I pulled it into the garage today and started going over it. Changed oil, checked shroud for critters, cleaned everything off, cleaned air filter, etc. Cranked it over and mowed about half an hour. She popped and quit. Looked things over for a few minutes, nothing noticible, except it was hot as fire. Cranked back up and it ran fine back to garage. Pulled into garage and I can actually hear the fuel in the carb sizzling. Tomorrow Im going to pull the head and check the valves and look at the carbon situation. The motor is strong and she is a mowing machine. Any quick pointers on what to look for? ddh

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BLT
Did you actually pull off blower housing? Carb bowl sizzling means it was getting radiant heat off block like no air flow to cool it. Are you sure you are getting good air flow?

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MysTiK
Cooling shrouds are little tins - were you able to see INSIDE the large blower at lower rear of engine? It's hard to see in there unless you at least loosen it, and peek. My K341 blows a nice breeze out the cooling fins = at IDLE with the hood up. Running lean, fuel starvation due to fuel lines, fuel filter, fuel pump, tank screen, gas cap vent, etc. not allowing adequate fuel to carb. or carb set too lean. on high idle jet. see manual for that, easy. But lean problem might be worse with full throttle mowing, constant fuel starve at higher throttle = lean. Possible old ethanol gas separation, accumulated goo, need carb clean? Ethanol gas should be bought in small quantities. or switch to premium gas. perhaps try seafoam Recent shocking thread here talked about oil sludge buildup - when you changed oil, did it refill with approx 1.9 liters, approx almost 2 U.S. quarts, approx 4 pints of new oil. SAE 30 oil. The shocker thread showed sludge that would not drain out, and refill capacity was about a cup or 2. That means little or no available oil. my best guesses.

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Charlieson
oil change was almost 2 qts. lean fuel makes sense, it is worse at full throttle. ill pull the shroud tomorrow, but there seems to be good flow. could be crappy gas also. hate ethanol gas.

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MysTiK
I tend to think BLT's suggestion is most likely scenario. Start it and idle, hood up, you can feel the breeze flow freely right out the cooling tins - if that isn't happening, then it can't cool itself at mowing rpm's. They do run hot, like any engine, maybe a little hotter; but not like you describe - carb cooking gasoline - wow. Stop mowing until you fix this - K341's are hard to find. Only run it to test any fixes. That kind of heat can intro other problems; but start with the cheap and easy fixes. Timing and valve clearances could be in play also, and can also relate to a lean condition. But big heat can indirectly mess up all of the above and more. warped heads, scored cylinders, baked oil residues, valve parts, gaskets, seals - you really don't want to go there, any more than you already have. Two other things: = make sure the exhaust is exiting the motor area, and not dumping that heat, and excess soot, under the hoody. = check for a cold weather kit that in cold weather or snow conditons can be added to increase carb temps for snowblowing, etc. Also, the opposite of that, would be a heat shield, designed to keep exhaust heat off the carb, during summer heat. happy hunting.

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Mack
quote:
Originally posted by Charlieson
oil change was almost 2 qts. lean fuel makes sense, it is worse at full throttle. ill pull the shroud tomorrow, but there seems to be good flow. could be crappy gas also. hate ethanol gas.
I usually mix a little Sea Foam in the gas. A lot of guys on the Cub Cadet sites like Marvel Mystery Oil in the fuel and oil on their Kohler's and say it works well on stopping some of the symptoms you describe. I would certainly be checking shrouds for debris and pulling the head to give a good cleaning first. Unfortunately getting the shroud off is best done with the engine removed from the tractor but not as big a job as that sounds. The K341 Kohler's are well worth the effort.

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sammiefish
even if there is good air flow you may wish to check if there is oil and junk on the fins hidden by the shroud on the back side of the cylinder ... possibly related to a leaky crank seal under the flywheel... therefore blowing oil up and through the fins accumulating gunk, hindering cooling.... if you start blowing head gaskets... don't just re-torque...in fact you may already have a leaky head gasket that leaks when overheated, and then run well when cool, that will work for a while... but...... don't ask how I know... B)

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Charlieson
removed motor. cleaned out 30+ years of dirt, mud dawbers, etc out. waiting in head gasket to reassemble. lots of dirt, but nothing mind blowing. ill repost after she is all back together.

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HubbardRA
Dwayne, When you put the engine back together, set the carb a little richer than you normally would. That would help some. Also when it starts acting up, pull the fuel line immediately and check for fuel flow. Also make sure that all the shrouds are in place. I have several Kohlers and all of the ones that are complete have a shroud that either covers the entire head or at least most of is. I have a couple other that I picked up that had the entire head open because somebody left the shroud off that covered the head. Without that shroud only one side of the head will get enough cooling airflow.

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MysTiK
Mr. Hubbard, thank you for the little edit on your post above. I thought, wow, you must really know something that no one else does. Although that is probably true in many cases; I agree, a slightly richer mix on the carb can alleviate overheating. It's interesting how fuel can be cooling; and also be a heat source. I don't think I could properly explain how that actually works; and perhaps it would be even more difficult to explain how less fuel, or a lean mix, can cause overheating. But such is the nature of the beast.

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HubbardRA
Graham, That was just a slip on my part. Sometimes I do things quickly and forget to read back over my posts. Too many things going on right now. Head is really not into tractors at the moment. I just check in once in a while to keep up on things.

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Charlieson
I think the major issue was the 30+ years of dirt that was around and under the flywheel. After removing the motor and cleaning everything up (no critter nests though) I could tell a real difference in the amount of air that blew over the top of the engine. I also took the head off and cleaned the carbon off (not to much for the age of the motor), changed spark plug, fuel filter, added some mystery oil to gas, and adjusted carb a bit. After assembling I mowed several hours with it and it didnt get hot (at least so hot it quit). I imagine the charger will work some better without all the dirt and dust on it also. Thanks for all the advise and suggestions. Hopefully she has another 30 years or so in her. The cyclinder walls looked practically new and she doesnt smoke at all. Strong tough mower. Much more power with this kohler 16 than my newer Simplicity Conquest with the 20 hp briggs. It mows better also. Only good thing about the Conquest is it will turn on a dime, whereas the Allis makes a wider turn. ddh

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