There is a chain sprocket on the front of the Yanmar 3gm30 in my 1979 Irwin Citation 39.5 which rotates as the engine runs. What is it's purpose? Also, the manual specifies .3L CD 30 weight oil for the transmission. Is this regular deisel engine oil and the rigth quantity? It doesn't seem like much. Thanks for the help, just got the boat and doing a lot of work without much information.
Yanmar 3gm30 sprocket
- Thread starter jluke
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Jluke.. Probably going to need pictures to see what it is.. The old 3 QM 30 Yanmars had a hand crank affair on the front that had a chain and sprocket set ..but the 3 G M 30's did not..?? If the plate on the side of the transmission says that it needs .3 Liter, that is correct.. It would be good to verify the engine model as 3 QM or 3 GM.. and then put eyes on the side plate of the transmission to see what it says.. Go by the nameplates, and not the manual ..
Thanks, I wonder now if the engine is a 3qm and not a 3gm. I'll check the plate next time over. By the way, I'm in Indian Landing up Bayou Castine. Not much room in the engine area, is there a stamping that would tell me the engine type?
I think there is a nameplate on the front of the engine with type and serial number.. same on the transmission.. ya might have to use a mirror to see the transmission plate.. Sometimes hard to read.. ?? I have attached pictures of a 3 GM F and a 2 QM 20.. A 3 gm30 would look like my 3 gmf.. a 3QM30 would look like the 2 qm20..A quick way to tell is the position of the high pressure injection pump.. on the 3GM's it is forward of and just below the top of the cylinder head.. The plungers are vertical.. On the QM's the pump is horizontally mounted on the starboard side of the engine block..
The shot with the sheet metal chain guard and crank sprocket is the QM the one showing the 3 front pulleys is the GM..
Another forum guy owns the boat "Lone Star" Not too far from ya..
OTHER NOTES: EDIT: The QM's were made in the 1976-1980 times.. The GM's were kinda in the 1983-2003 years.. If the boat was not re-powered, it is probably a 3QM30.. But the plate on the front of the engine will tell the tale..
The shot with the sheet metal chain guard and crank sprocket is the QM the one showing the 3 front pulleys is the GM..
Another forum guy owns the boat "Lone Star" Not too far from ya..
OTHER NOTES: EDIT: The QM's were made in the 1976-1980 times.. The GM's were kinda in the 1983-2003 years.. If the boat was not re-powered, it is probably a 3QM30.. But the plate on the front of the engine will tell the tale..
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Thank you, I'll be back over there next week and will take a close look for plates. I think you are right, probably a QM.
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