3GMF Question

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Jun 3, 2004
418
Island Packet Island Packet 29 West River, MD
Can someone explain this to me? My manual reads as follows: Continuous Rating Output (DIN6270B) - 20HP / 3400RPM One Hour Rating Output (DIN6270B) - 22.5HP / 3600RPM The Yanmar plate on the engine says 20HP / 3600RPM (lower HP but higher RPM). I had the engine serviced in the fall and though the tach maximum reads 2900RPM the Yanmar mechanic said I was turning at 3800RPM!!! I'm assuming he was a little high. Why the differences? Is the engine a 20HP or 22.5HP? What about the differences in RPM's? Thanks, Joe Mullee
 
Dec 25, 2000
6,052
Hunter Passage 42 Shelter Bay, WA
Joe, I interpret it to mean that your engine...

is designed to run continuously (24x7) at 3400 RPM and at that rate produce 20 HP. It is also designed to run at the higher RPM, produce the 22.5 HP, but only for short periods of time; one hour. I presume they print the difference to indicate that the engine is not designed to run under load continuously at the higher RPM. Bud
 
Dec 2, 2003
4,245
- - Seabeck WA
Joe,

I tuned in because you said you had a 3GMF question. You have a different engine. Maybe the 3 should have been a 2?
 
Jun 3, 2004
418
Island Packet Island Packet 29 West River, MD
Definitley a 3

I'm just trying to figure out what the actual RPM's are when my tach is reading 2900, which is the max it reads. The mechanic says his hand held tachometer shows 3800 but I'm guessing that's too high based on the information in the manual. Again, the manual says 3400RPM continuous and 3600RPM for the one hour rating.
 
Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
Tachs and Hp

Joe, Actualy the no load max RPM seting for the govenour is 3750 +/- 50 RPM. So 3800 could be posible. I'd suspect you tach is off. It's not uncommon for a tach to have a discrepancy. A 3GMF should be 20hp @ 3400 RPM continous with a Max of 22.5 at 3600 for 1 hour. Look at your tag again amd make sure your not reading the kilowatt rating. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
 
E

Ed

tach

Maybe you should concider getting the right tach. It could tell you lots of things like if your proped right and keep you from blowing to top off your little motor!
 
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