Curious about air cooled engines

rrman61 · Apr 25, 2023

What allows an ar cooled engine to not overheat while a liquid cooled engine must have coolant/water pump?and would adding an exterior fan to an air cooled engine do any good on a Honda 300 air cooled engine?

cole in mo · Apr 25, 2023

(quoted from post at 11:52:54 04/25/23) What allows an ar cooled engine to not overheat while a liquid cooled engine must have coolant/water pump?and would adding an exterior fan to an air cooled engine do any good on a Honda 300 air cooled engine?

Keeping an air cooled engine running at rated speed, the air intake shroud clean, and any build up of dirt and crud from the cyl fins, things like will keep one cool.

BarnyardEngineering · Apr 25, 2023

Air cooled engines have cooling fins on the cylinders, while a liquid cooled engine is smooth on the exterior.

Most air cooled engines these days already have baffles and fans to push air around the cylinders. Even a simple Briggs and Stratton style engine. The fan is on the flywheel, and the recoil shroud is designed to direct air around the cylinder.

Whatever this "Honda 300" engine is, it probably is already designed for optimal cooling. Adding a fan in the wrong place may be counterproductive.

UncleTom · Apr 25, 2023

I bet the honda 300 also has an oil cooler.

MarkB_MI · Apr 25, 2023

Air-cooled engines are typically built to looser tolerances to allow for greater expansion as they heat up. Obviously, there are tradeoffs to this, which is why current production automobiles are all liquid-cooled.

Stationary air-cooled engines all have cooling fans that are designed to move enough air to keep them from overheating at rated power and typical ambient temperatures.

moresmoke · Apr 25, 2023

Are you referring to an ATV or motorcycle Honda 300? The fins are enough cooling at idle to keep them cool, but rely on air movement from travel speed to cool them at higher power levels. If you use an air cooled ATV for work in the low gears they will overheat.

cjunrau · Apr 25, 2023

If you are talking atv. The 400 they added an oil cooler with fan in front of engine for exactly that reason. If you added a fan I think you would over load the charging ability on the quad. As long as you are moving the 300 will not over heat. I cultivated my garden and did 2 rows then cruise down the road then did 2 more. If I didnt it would over heat.

BarnyardEngineering · Apr 25, 2023

(quoted from post at 04:37:20 04/25/23) I bet the honda 300 also has an oil cooler.

Bet it doesn't. If it did it would have a very obvious "radiator" on the front and the OP would assume it's "liquid cooled" and would not be asking about air cooled engines.

Geo-TH,In · Apr 25, 2023

This JD has a twin cylinder 17 hp water cooled kawasaki.
The hood came off a different JD.
I've done everything to keep grass clippings out of the radiator. We use a leaf blower to clean the radiator before we use it.

This JD has a single cylinder 17 hp air cooled Kawasaki.
Never had an issue with grass clippings

This JD has a 38 hp diesel. The neighbor says he has to clean the grass clippings off his radiator before using.

Blackhole49 · Apr 25, 2023

Milwaukee Vibrators (Harley's) use to be notorious for overheating in stop and go traffic.

Eric in IL · Apr 25, 2023

Years ago I added a fan to a Polaris Trail boss. It got plenty warm in the summer when I used it for spot spraying.

The fan was about 4 inch diameter and I mounted it to the frame pointed toward the engine head. Operated it with a toggle switch on the handlebar. Worked great.

dr sportster · Apr 25, 2023

rrman61 · Apr 25, 2023

4 wheel drive atv

Fritz Maurer · Apr 25, 2023

Looser tolerance like where, for instance?

MarkB_MI · Apr 25, 2023

> Looser tolerance like where, for instance?

I meant 'clearance' rather than 'tolerance'. I believe the pistons tend to be looser in their bores on a air-cooled engine compared to a similar liquid-cooled engine.

oldwrencher · Apr 25, 2023

i have an 89 suzuki 250 that has a factory supplied cooler fan that i had the dealer install when it was newer. it has a thermostat switch that may or not work now so when spraying I turn it on manually. Don't know if it helps, but relieves worry about overheating.

Russ from MN · Apr 25, 2023

My Honda 400 Foreman ATV has an oil cooler with a fan, normally the fan doesn't run, but when I'm traveling slow in warmer weather spraying, then it does run off and on. Most air cooled engines have fans, only motorcycles and some ATV's don't. The older Volkswagens had big fans and a thermostat to maintain a proper temperature.

buickanddeere · Apr 25, 2023

(quoted from post at 06:52:54 04/25/23) What allows an ar cooled engine to not overheat while a liquid cooled engine must have coolant/water pump?and would adding an exterior fan to an air cooled engine do any good on a Honda 300 air cooled engine?

They can overheat, you just won t observe and coolant boiling off .

Deutz Lover · Apr 25, 2023

Both Volkswagon and earlier Deutz diesels were air-cooled. I imagine they would benefit from synthetic oil since these can withstand higher temperatures. Air cooled engines heat up quicker and in the case of Deutz engines there is less initial upper cylinder wear at startup because the ignition gases do not condense on the cylinder walls. All forced air cooling engines will very quickly develop problems if cooling is lost or impaired. So will water cooled engines, but they will be slower to croak.

dr sportster · Apr 26, 2023

Cooling fins to dissipate heat. Gotta keep it in the wind.

Curious about air cooled engines

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