I want to change from a 2 blade prop to 3 blade. In order to do this I need to know the following for the 2QM20 engine. 1. Max brake horsepower. 2. Max rated rpm. 3. Governed at what rpm. I have a Hunter 36 built in 1980 and have not been able to find a manual for the engine. Any help would be very apperciated.
- Status
No engine placard?
Carl: You engine should have a placard on the front of the block. You also need the transmission reduction ratios to order ANY prop. From what I can see, the engine is rated at 22hp at 3000 (max) and the continous ratings of 20hp at 2600 continous. You should probably contact Mack Boring for the specs. If you are getting the proper performance out of the 2 bladed prop you can usually estimate that you will either reduce the pitch by 1 deg. or decrease the diameter by 1" when you add a blade. But is really best to get all of these specs for the Prop Guy so you have someone else to blame if it does not perform as sold. You should be able to rev your engine to the max rating while it is out of gear. You should also be able to get within about 100-200 rpms of that max rating when in gear too.
Carl: You engine should have a placard on the front of the block. You also need the transmission reduction ratios to order ANY prop. From what I can see, the engine is rated at 22hp at 3000 (max) and the continous ratings of 20hp at 2600 continous. You should probably contact Mack Boring for the specs. If you are getting the proper performance out of the 2 bladed prop you can usually estimate that you will either reduce the pitch by 1 deg. or decrease the diameter by 1" when you add a blade. But is really best to get all of these specs for the Prop Guy so you have someone else to blame if it does not perform as sold. You should be able to rev your engine to the max rating while it is out of gear. You should also be able to get within about 100-200 rpms of that max rating when in gear too.
Try Torresen
Carl. Try the link bellow and go poking around for your model number. You may be lucky. http://www.marinedieseldirect.com/yanmar/
Carl. Try the link bellow and go poking around for your model number. You may be lucky. http://www.marinedieseldirect.com/yanmar/
Write if you need. . . .
more info. I have the 2QM20 Maintenance manual at home. I think the previous responses covered what you need to know. My H37C has the same engine, the tranny is 2:1. I put a Flex-O-Fold(2-blade) on, would rather sail fast than motor.
They also make a 3-blade and were able to fit the right dia./pitch to my boat(see Link). Ed h37skipper@aol.com
more info. I have the 2QM20 Maintenance manual at home. I think the previous responses covered what you need to know. My H37C has the same engine, the tranny is 2:1. I put a Flex-O-Fold(2-blade) on, would rather sail fast than motor.
They also make a 3-blade and were able to fit the right dia./pitch to my boat(see Link). Ed h37skipper@aol.com- Status