big twin generator

[djwlbk]

I have a 1964 40 hp big twin and it looks as though it came with a generator. Any ideas where I might find one for it?

 

[Chris1956]

Re: big twin generator

You will also need the voltage regulator and a belt to power it. From what I understand the generators are pretty rare, and the VRs are expensive.

I would opt for a Marine deep cycle/starting battery, and charge it every few weeks. The motor is mechanical shift right? If it is electric shift, you do need to figure out something, as the elec shift motors came with gennys.

 

[tx1961whaler]

Re: big twin generator

The electric shift does not require a generator, but all of the electric shift models had them. A deep cycle will still run an electric shift a couple of days without a recharge.

 

[F_R]

Re: big twin generator

However, if you run it with a severly discharged battery, the clutch will slip and wear, and that will cost you more that fixing the generator.

 

[tx1961whaler]

Re: big twin generator

However, if you run it with a severly discharged battery, the clutch will slip and wear, and that will cost you more that fixing the generator.

Quite correct. The clutch and spring assy is north of 400 bucks now. I seem to remember that the current draw of the coil was something close to 2 amps when in gear?

 

[samo_ott]

Re: big twin generator

I ran my big twin 25hp all last summer with electric start with a small 1 square foot solar panel to keep the battery charged. It worked well. Never had to charge it once. Way cheaper and easier than worrying about a generator and all that goes with it. And those old generators were not efficient anyway.

 

[F_R]

Re: big twin generator

Quite correct. The clutch and spring assy is north of 400 bucks now. I seem to remember that the current draw of the coil was something close to 2 amps when in gear?

Close. Spec is 1.5 to 1.9 amps.

Not efficient? The generator puts out a regulated 10 amps at above 1/3 throttle all the way up to wide open throttle. And the voltage is regulated to 14.5 volts. Compare that to the 5 or 6 amps maximum delivered by the (modern) unregulated alternators that often go as high as a battery bustin 16 volts or more. Of course we do have the option of the regulated systems with super $$ expensive rectifier/regulators nowadays.

 

[samo_ott]

Re: big twin generator

But how many hp does it take to get those 10 amps... A lot from what I understand...

 

[Chris1956]

Re: big twin generator

I was taught that generators and electric motors are 99% efficient. So, 12VDC*10A = 120 watts. Since 700W=1HP, the generator should need 1/5 HP or less.

 

[F_R]

Re: big twin generator

I agree that there is no such thing as a free lunch and it takes power to turn the generator. However, I have run many motors, both my own and customer's, and for the life of me, I can't tell the hp difference.

There is no such thing as a free lunch on the flywheel alternators either. It takes power to turn them too. If that were not so, you could use a little waterfall to turn an alternator to light up the city.