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prop rpm

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leanderbarrie

New member
hi everyone

i have an '66 Mercury 500 thunderbolt which i have a question about.

i need to know what rpm's the propellor makes when the motor is running?
and also maybe the rpm the axle makes where the engine is mounted on.

If someone knows this please tell me or if someone has a characteristic or something?

Thanks for reading this and helping me

Regards Leander
 
Put the machine in forward gear.------Turn the flywheel until prop starts turning.----Now mark the prop and the flywheel.------------Turn the flywheel 10 times and count how many times the prop turned.------Multiply the #'s by 500 to see what it would at 5000 RPM
 
well the problem is that the engine is of the motor. because the engine is broke, and it was to expensive to repair it, zo i'm going to try to install an electric motor on it.. but i need to know the normal rotations of the prop because it needs the right rotation speed right? thats why i need to know the rotations. instead of the flywheel, can i mark the axle as well and then turn the prop to see how many times it rotates?
 
Same thing by rotating the drive shaft ( axle )-----------You would want to remove the waterpump as well when you put this in operation.
 
Man your gonna need a very big extension cord????Usually the electric motors don't have the tourqe to operate a drive.Your gonna need reostats? and regulators, lots of batteries and lots of stuff. Probably not gonna work.
 
Correct on both points. When I restore old Mercs, I always replace the fuel lines and fuel pump diaphragms since the "Evil-Nol" gas will eat them up.

Jeff
 
well i was allready so far to remove the waterpomp cus else it will give a little problem.. and why wouldn't it work? if you search it on internet, you can find electric powered motors. at least i can give it a try.. but thanks anywa everybody for the support. if it works, i will deffinetly post it.

regards Leander
 
You might be surprised at how much power is needed to turn the bearings and gears in the lower end.-----Might help to remove reverse gear ( less drag ) and put a thin oil in it.
 
i looked for it and i found out that 1 turn on the prop is 1 and 2/3 turns of the axle ( thats almost 2:1) but if this would be the normal engine and i give full power, which rpm's does the prop makes then?
 
Boats don't have axles and I am thinking that you would need enough batteries to sink the boat to even power the thing and the cost would be well and beyond buying another engine to replace the one that you took out imo.
 
Its going to be hard to find a DC motor that turns 6000-7000 rpm that is not 50VDC and doesnt need a lot of amps(batterys) and have torque to turn prop. The more load you have on prop will cause motor to draw more amps,
 
Hi, I work with electric motors for a living. I converted a jeep, 2000 model to work with an electric motor. The motor has much less horsepower than the original, it now only has an 18HP motor. The cost of the batteries needed was ridiculous. 15 000 US dollars more or less. This excludes the inverter and battery chargers. I agree that the cost is not worth it. This money could have bought the guy a new vehicle with more horsepower and speed.
 
:p electric outboard.jpg
I'm almost done with mine. I just need to get 3 phase to my boat.:p
 
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