I have both the 18 and 20 HP kohler magnun all seems well but I worry about how hot they both seem to run. . The motor blower fans work great and the screen air duct down below is 100% free of debree. Seems as though even only after minutes of running the motor is to hot to even check the oil after being turned off. I know If a motor gets to hot it will not restart until it cools down. Both my motors restart instantly. I know and reailze these are air cooled and should run hot but is this normal to run that hot? Any help or thoughts would be more than welcome. On the 18 HP I took off the upper and side heat shields to see if that helped. Seemed to run slightly cooler. I've never liked the design of the upper heat shield that seems to trap in the heat from the very hot muffler. Bruce
Hello Bruce ...
Be careful removing the heat 'shields', they are actually there to direct air flow to cool the engine properly... ESPECIALLY the top ones, they insure the valves do not over heat :tongue:...
The best thing you can do for an air cooled engine is run an oil that can function WELL in high temperatures. That is exactally where a full synthetic is the best. I run Shell Rotella T6 5-40 in ALL my engines gasoline and diesel... but definitely in any air cooled engine. :smile:KennyV
Hi Bruce,
Your Magnum engines are cast iron blocks and are of an older technolgy. Most of your current engines are made of aluminum which disapates heat diffrently. As far as the heat shields, the other gent that posted "be careful" is correct. All engines are designed to operate at spec temps. Although it may run hotter than a new one, the gaskets and seals that were placed on that engine at the time of manufac are designed for that temp range providing that the cooling fins, shields, flywheel fins, and intake screen are all in place and are not restricted. This also means the block is free of mud, grease and other items that insulate that heat. As far as the oil type, synthetic oils have come along way in technology,but running another weight oil other than what is specified can do damage to your engine. Oil isn't oil. There are reasons for all those numbers on the container not to mention the letter designations. Just because someone has good luck with a certain type of oil, doesn't mean you will too. Always refer to manufacturer specs for optimal performance. Those gaskets and seals I mentioned above are only rated for a temp range that is RELATED TO THE OIL TYPE. I hope this helps.
Hello Everyone, and many thanks for all your help and replies. The main concern I had was that the motor runs as hot as it does and I guess from what you all say that is thought to be normal and it is build to run that way. Makes me feel better to know this is normal. I blow the motor often as I see it getting dirty even more so in the rear of the motor fan area against the motor block too behind the fan blades. My 18 HP has an external oil filter with a long oil line. I always liked that option so as to keep the oil slightly cooler. Thanks for this great site and people that are in it.......Bruce :smile:
I have a cub model 1811. The Kohler gets very hot. The side sheilds of the tractor probably help keep the heat in. I dont remove them for fear of getting dust or dirt in on the engine. Then it would really run hot. All the cubs with the outside sheilds all run very hot. I have 730 hours on mine and it runs great........
I dunno, if a stationary engine has a way to move more air at higher throttle that's fine. If not it will get hotter, convection can only do so much. I'm sure they all have a sweet spot of RPM vs Temp.
i have a cudet with the 18 hp kohler magnum some times just blowing off the dust & dirt is not good enough i power wash the engine to remove any oil or grease build up on the heads & block any build up will make the motor run hotter
I think the Kohlers run hotter than the others. I have an older Snapper garden tractor that has a Kohler 18 horse on it. Once that engine gets up to operating temperature, you can see the heat waves out in front of the tractor while you are using it. When I first got it, it concerned me a little. But now it has nearly 1,100 hours on it and it's still going strong.
Bruce, Too hot to touch is not a reliable indication of heat. Your frying pan is usually 350F to cook bacon,but that's a danger zone for an aluminum head. IMO synthetic oil will not cool any better than regular oil. AC engines are all on the edge of overheat when doing hard work in hot weather IMO. Lots of threads in this forum
That is Not why you should use Synthetic oil.
You use a good Synthetic Because the oil WILL occationally incounter temps that will burn regular mineral oil... The Synthetic Will not burn into carbon. It is not only going to continue cooling But it will Also continue lubricating ... Mineral oil that has been over temped will not....:smile:KennyV
That is Not why you should use Synthetic oil.
You use a good Synthetic Because the oil WILL occationally incounter temps that will burn regular mineral oil... The Synthetic Will not burn into carbon. It is not only going to continue cooling But it will Also continue lubricating ... Mineral oil that has been over temped will not....:smile:KennyV
Kenny, If by mineral oil you mean auto spec oils I have discussed this often on this forum and my position is unchanged . If you operate in sub freezing temps or high rpms (racing or trimmer ) synthetic is better. In other applications the auto spec oils with their additive paks are good way out to 300F where some additives may weaken. "Flash" where oil becomes vapor and ignites is out at 390F and the synthetics are a little better out there. But out there you've already lost the head Even my Intek which ran 300F when it came apart (twice) showed no signs of lubrication problems with Chevron 10-30. In summer it holds 35-40 psi on oil gage at 270F sump with its original journals/bearings. :smile:
