Brockport Bill 1,932 #1 Posted May 2, 2024 sorta a curiosity question -- i have owned and used a 312-8 with the Kohler 12 hp single cylinder since new in 1989 - - but now also use a c175h with the twin Kt17 Kohler 17 hp engine -- was wondering... is this twin with the 2 cylinder (and a hydro) likely to burn essentially twice the gasoline? I have not measured comparison gas usage but was wondering from the engine science mechanics here on RdSq what the likely gas usage comparison would be --- OR -- if anyone has kept track and measured the difference in gasoline useage from their single cyl versus twin Kohlers -- thanks for any insights - Bill 1 Share this post Link to post Share on other sites
JoeM 8,293 #2 Posted May 2, 2024 Yes, the these engines are fairly inefficient. The only time they burn more is on the governor. Cubic inches need feed with fuel and the hydro, for the convenience of operation, can be up to 20% parasitic. They generate a lot of heat. I do know the onan 20 hp burns a lot of fuel compared to a Kohler 20 hp CH engine with very little difference in HP. The newer OHV Kohlers are pretty sweet. I know I was pleasantly surprised to see a nice fuel use decrease when I switched over to all non e. But she is about 70 cent higher on price. With about half of this stuff sitting in the shed, I like not having carb issues. 2 1 Share this post Link to post Share on other sites
ebinmaine 72,426 #3 Posted May 2, 2024 Our whole Herd is Kohler singles at this time. Trina's 8 HP engines SIP fuel. My K341 16 HP engines probably do use right around twice as much...but... I AM larger. The TRACTORS are larger and heavier. The LOADS I pull are heavier. My PLOW is substantially wider. So yes.... more fuel usage. And.... A LOT more work being done. My K582 Twin for Colossus has only been running for a few minutes at a time. That big beast GUZZLES petro in comparison to the others. 2 Share this post Link to post Share on other sites
Fordiesel69 271 #4 Posted May 3, 2024 I have mostly all kohler singles and some briggs twins. I find the kohler 10 (k241) provides the best fuel consumption with a 42 SD deck in third gear. And most 12HP K301/M12 are second best with paired with the 8 speed. Now onto the twin 16hp briggs, they guzzle fuel. Not twice but close to twice. 2 Share this post Link to post Share on other sites
953 nut 59,782 #5 Posted May 3, 2024 Like @JoeM said, you are feeding cubic inches. Your 312-8 has a 30 CID engine and the C-175 has a 42 CID engine so the twin cylinder engine requires 140% as much fuel/air mixture per revolution. I generally mow with a 310-8 and 42" deck, when I picked up ny 418-C with a 48" deck I mowed with it a couple of times. Fuel consumption with the K-Twin was about one and a half times what the single cylinder engined 310 uses but finished in less time using the hydro rather than stopping and shifting as much and the 12% larger cutting deck. The 418 is far superior to the 310 when it comes to snow plowing and that is its primary function for my needs. The added power of the 18 HP enables plowing snow up the steepest parts of our driveway while the 10 HP could only plow going down hill. With the 310 for mowing I get more seat time in the summer when it is enjoyable, with the 418 I get the job done faster in the winter when I want to get back inside to warm up. 4 Share this post Link to post Share on other sites
Pullstart 66,635 #6 Posted May 3, 2024 Not to mention the extra rotating mass and moving parts that need energy in the twin engines… 2 Share this post Link to post Share on other sites
kpinnc 14,585 #7 Posted May 3, 2024 16 hours ago, Brockport Bill said: have owned and used a 312-8 with the Kohler 12 hp single cylinder since new in 1989 - - but now also use a c175h with the twin Kt17 Kohler 17 hp engine -- was wondering... is this twin with the 2 cylinder (and a hydro) likely to burn essentially twice the gasoline? I Oddly enough, you're using almost equal amounts of available HP in this situation. One just drinks more fuel. An 8 speed transmission requires very little input horses. One or two is more than required for forward motion. But the hydro requires 4+ HP just to operate. So your 17HP engine gets reduced to 13 before you engage the clutch. Not hating on hydros at all. Just keep things like this in mind when figuring efficiency. Your 312 may actually have nearly as much available power for a given implement as your C175 does. 1 Share this post Link to post Share on other sites
OutdoorEnvy 1,766 #8 Posted May 3, 2024 Not super scientific but a good practical comparison…My buddy mows 2.25 acres. He has mowed it with his 417-A with 42rd deck and cannot mow it without refuelling. He estimates it runs out with half an acre or so left. He has borrowed my 312-8 with 42sd deck to mow it and did not need to refuel. 3 Share this post Link to post Share on other sites
JoeM 8,293 #9 Posted May 3, 2024 2 hours ago, 953 nut said: finished in less time using the hydro rather than stopping and shifting as much Never gave that a thought I know with the hills and layout of my grass, a gear-drive would cause a lot of unnecessary juking and jiving to cover the same ground then the hydro by far. 2 Share this post Link to post Share on other sites
Brockport Bill 1,932 #10 Posted May 3, 2024 3 hours ago, 953 nut said: Like @JoeM said, you are feeding cubic inches. Your 312-8 has a 30 CID engine and the C-175 has a 42 CID engine so the twin cylinder engine requires 140% as much fuel/air mixture per revolution. I generally mow with a 310-8 and 42" deck, when I picked up ny 418-C with a 48" deck I mowed with it a couple of times. Fuel consumption with the K-Twin was about one and a half times what the single cylinder engined 310 uses but finished in less time using the hydro rather than stopping and shifting as much and the 12% larger cutting deck. The 418 is far superior to the 310 when it comes to snow plowing and that is its primary function for my needs. The added power of the 18 HP enables plowing snow up the steepest parts of our driveway while the 10 HP could only plow going down hill. With the 310 for mowing I get more seat time in the summer when it is enjoyable, with the 418 I get the job done faster in the winter when I want to get back inside to warm up. With the 310 for mowing I get more seat time in the summer when it is enjoyable, with the 418 I get the job done faster in the winter when I want to get back inside to warm up. love that comment!!! 2 Share this post Link to post Share on other sites
Brockport Bill 1,932 #11 Posted May 3, 2024 2 hours ago, kpinnc said: Oddly enough, you're using almost equal amounts of available HP in this situation. One just drinks more fuel. An 8 speed transmission requires very little input horses. One or two is more than required for forward motion. But the hydro requires 4+ HP just to operate. So your 17HP engine gets reduced to 13 before you engage the clutch. Not hating on hydros at all. Just keep things like this in mind when figuring efficiency. Your 312 may actually have nearly as much available power for a given implement as your C175 does. interesting comparison of HP in gear vs hydro -- i have used my 312-8 for plowing, mowing and tiller - and the 175 for plowing and mowing but no tiller -- i have told people for 35 yrs i have never had the 312-8 in a situation it needed more hp -- always handled every task -- i suspect thats also the engineering and design of the legendary gear tranny as well 2 Share this post Link to post Share on other sites
Brockport Bill 1,932 #12 Posted May 3, 2024 2 hours ago, OutdoorEnvy said: Not super scientific but a good practical comparison…My buddy mows 2.25 acres. He has mowed it with his 417-A with 42rd deck and cannot mow it without refuelling. He estimates it runs out with half an acre or so left. He has borrowed my 312-8 with 42sd deck to mow it and did not need to refuel. thats a great representative comparison -- exactly the kind of head to head comparison i was wondering 2 Share this post Link to post Share on other sites