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View Full Version : O/T Gas generator dis-assembly



radkins
07-22-2009, 02:16 PM
It seems that no matter what the problem someone here always seems to have the answer! :) I am trying to dis-assemble, that is remove the motor, a 1970's Montgomery Ward 7 HP gasoline generator. This is the very common Briggs&Stratton type of generator sold by several home and building supplies during the 60's, 70's and early 80's. I need to remove the motor from the generator and can not seem to be able to separate the two, I have not yet gotten forceful with this thing since that can get expensive or end the project entirely so I decided to seek advice first.

agrip
07-22-2009, 03:46 PM
Suspect that the rotor is mounted on a male taper on the engine crankshaft.

Remove the free end plate (not necessarily the bell) and look for an end screw on the rotor shaft.
If found remove screw DO NOT use the fan to resist rotation, usually plastic and won't cut the mustard.

If screw is about 6" long or some such,remove fan and possibly the end bell. Watch out for sliprings and brushes.

Put a stout pin into the hole to fit past the deep threads the screw came from.
The pin needs to be cut off so a short screw in larger threads in rotor hole will act as a jack screw on the pin and POP the rotor off.

My pin is made from a piece of #2 philips screwdriver.
Others have been made from a turned down pin punch.

Hth Ag

mototed
07-22-2009, 06:12 PM
Excellent advise agrip, I've worked on many Honda generators and they are the same setup. I would like to add, considering the age of the generator, you need to soak the taper area with penetrating oil, and ring with a hammer lightly to set up a vibration to get the oil to creep in.

Dawai
07-22-2009, 06:57 PM
Sometimes the motor-shaft is one inch and about a foot long.

Brass hammers ring, release tapers. I keep one for my morse tapers and the harley flywheels.

If it is the type I am thinking of it has a threaded end on it also. I forget whether it has a threaded armature or a nut on the end tho.

radkins
07-23-2009, 12:25 AM
Suspect that the rotor is mounted on a male taper on the engine crankshaft.

Remove the free end plate (not necessarily the bell) and look for an end screw on the rotor shaft.
If found remove screw DO NOT use the fan to resist rotation, usually plastic and won't cut the mustard.

If screw is about 6" long or some such,remove fan and possibly the end bell. Watch out for sliprings and brushes.

Put a stout pin into the hole to fit past the deep threads the screw came from.
The pin needs to be cut off so a short screw in larger threads in rotor hole will act as a jack screw on the pin and POP the rotor off.

My pin is made from a piece of #2 philips screwdriver.
Others have been made from a turned down pin punch.

Hth Ag


I have this thing now stripped down to the Armature, after removing the end plate the outer generator housing just slid right off leaving the Armature hanging on the engine crankshaft with a plastic fan between it and the motor case. In the free end of the Armature shaft there is a very puzzling arrangement, it looks as if the shaft is counter-bored for a cap screw leaving the screw (if that is what it is) recessed slightly inside the shaft end. This cap screw (?) has an odd head that looks very similar to a Torx drive head but a T-50 is just slightly too small and a T-55 is too big, it also has something like an insert of some kind in the center so I am not at all sure it is even a screw/bolt. If I can figure out how to post a pic of this thing I will try to get one of it as soon as I can, it sure has me puzzled at this point.



BTW, there does not appear to be set screw of any kind in the shaft end where it connects to the engine crankshaft.

rancherbill
07-23-2009, 12:34 PM
What's the exact model number on the engine. You can look it up and find out about the taper etc and removal procedures.

If you can't find it, I have some good BS links.

radkins
07-23-2009, 02:40 PM
What's the exact model number on the engine. You can look it up and find out about the taper etc and removal procedures.

If you can't find it, I have some good BS links.


Thanks, I would greatly appreciate any info I can find since I did not come up with what I needed on the net, I did the Google search before asking here. How this Armature is attached to the crankshaft sure has me puzzled big time, I am becoming more convinced that what I am seeing is not a screw/bolt after all although it may very well be. If it is I am not at all certain what tool would be used to remove it, I have never seen anything quite like it.

If this is indeed a bolt in would be either a 3/8" or maybe even a 5/16" about 9" long or maybe a bit longer and would have to extend from the free end of the Armature shaft to the end of the crankshaft.

Guido
07-23-2009, 04:36 PM
YMMV so don't tear anything up---but, just my observations. 6.5 Onan genset has a hex head screw looking at you from the end of the armature, recessed just like you described for your Torx socket. The motor output shaft seats into a Morse taper machined into the input end of the armature shaft. The taper is secured/maintained by tension applied by a 3/8 in. dia. hex headed screw, which extends the lenth of the armature, inside the shaft.

To separate the two shafts, we loosened the hex head screw a couple of turns, then thumped with a brass hammer. Morse taper was simply doing it's thing. The screw had about two inches of theads to transfer energy to the motor shaft.

G

radkins
07-23-2009, 05:19 PM
YMMV so don't tear anything up---but, just my observations. 6.5 Onan genset has a hex head screw looking at you from the end of the armature, recessed just like you described for your Torx socket. The motor output shaft seats into a Morse taper machined into the input end of the armature shaft. The taper is secured/maintained by tension applied by a 3/8 in. dia. hex headed screw, which extends the lenth of the armature, inside the shaft.

To separate the two shafts, we loosened the hex head screw a couple of turns, then thumped with a brass hammer. Morse taper was simply doing it's thing. The screw had about two inches of theads to transfer energy to the motor shaft.

G


Ok I will try once more to get this thing loose, maybe I was just afraid to apply enough force to the screw. I am assuming it is a regular RH thread?

radkins
07-23-2009, 06:11 PM
YMMV so don't tear anything up---but, just my observations. 6.5 Onan genset has a hex head screw looking at you from the end of the armature, recessed just like you described for your Torx socket. The motor output shaft seats into a Morse taper machined into the input end of the armature shaft. The taper is secured/maintained by tension applied by a 3/8 in. dia. hex headed screw, which extends the lenth of the armature, inside the shaft.

To separate the two shafts, we loosened the hex head screw a couple of turns, then thumped with a brass hammer. Morse taper was simply doing it's thing. The screw had about two inches of theads to transfer energy to the motor shaft.

G


As soon as I read this I went out to the shop and re-installed the flywheel to have something to lock the crankshaft with then using an Allen wrench which fit half of the flats in the screw head (this thing turned out to be a 12 point socket instead of a Torx) I took the plunge and really bore down on it this time-IT WORKED! The darn thing is finally out! :D

Thanks everyone I genuinely appreciate each response. Although this turned out to be quite simple it was anything but simple until I got it out and now know I am not screwing up an un-obtainable part!

rancherbill
07-23-2009, 10:55 PM
Thanks, I would greatly appreciate any info I can find since I did not come up with what I needed on the net,


BS made /makes lots of engines, can you post the model /serial number? It is the key to unlocking the mystery.

radkins
07-24-2009, 12:55 AM
BS made /makes lots of engines, can you post the model /serial number? It is the key to unlocking the mystery.


I meant to do that earlier but I forgot,

model no. is 170412

type no. 1723-01

code no. 78061512


I think there is a serial no. also but I don't have that right now, I will check and get that too.


Well I was delighted that I had finally gotten that bolt out but the Armature is now being very stubborn about separating from the crankshaft taper. As of now I can't see anyway to attach a puller and the housing from the rear of the generator prevents accessing the rear of the Armature where it fits to the shaft, this housing can't be removed until the separation is made.:mad:

radkins
07-24-2009, 01:04 AM
Put a stout pin into the hole to fit past the deep threads the screw came from.
The pin needs to be cut off so a short screw in larger threads in rotor hole will act as a jack screw on the pin and POP the rotor off.Hth Ag


The only threads I have found so far are the ones in the crankshaft for the through bolt in the Armature. Are the larger threads located near the rear of the hole close to the end of the crankshaft?