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I was given a Parmac S5000 gas generator last month by a friend going into a nursing home. He was given the generator six years before that but said it never ran right. His wife's brother bought the generator new a few years before that but also said it never ran right. Lucky me right?

The Jaguar 9hp engine over runs like the governor is bad. The governor shaft will turn 360 so I decided to repair or replace the governor shaft or governor itself.

I got the engine and the governor separated about two inches but that all. I can't get the engine shaft to let go the governor shaft. The outside bearing you can see in the photos has separated but the shafts are still together.

I've worked it loose by tapping on the cases but now I worried I'll damage the plastic fan blades on the governor shaft. In one photo the plastic is getting torn so I stopped.

Has anyone had trouble separating two shafts? I expected a key to fall out and the shafts free.

I may have found the problem.

there is a bolt I need to remove that's holding the arm shaft to the crankshaft.

I'll post if this works tomorrow.

The internet videos show hitting the arm shaft to dislodge the generator. I have been hitting the arm several times every day but so far it has not broken free.

Any other ideas would be a help. Has this happened to anyone here?

The model number would be really nice so I could look it up and see what might possibly be going on.

the engine is a 9hp Robin E27, the generator is a Macc Alte Spa Ar1-130/2

I found the diagram for the Mecc Alte. It shows a threaded bolt at both ends thru the arm shaft with a washer and a cap/nut on the end of the bolt shaft.

the capnut come off easy but the arm shaft itself refuses to let go of the engine crankshaft.

I have a 4lb dead blow hammer and I have hit the arm like it shows but the refuses to come off the engine.

I have reached the point since the 5000W generator was a hand me down and did not cost me anything I'm ready to beat it to death and if I break it beyond repair it's going to the street to hand it down to another sucker.

But if you can help, I'm ready for it, Thanks

TheBishop said:

the engine is a 9hp Robin E27, the generator is a Macc Alte Spa Ar1-130/2

I found the diagram for the Mecc Alte. It shows a threaded bolt at both ends thru the arm shaft with a washer and a cap/nut on the end of the bolt shaft.

the capnut come off easy but the arm shaft itself refuses to let go of the engine crankshaft.

I have a 4lb dead blow hammer and I have hit the arm like it shows but the refuses to come off the engine.

I have reached the point since the 5000W generator was a hand me down and did not cost me anything I'm ready to beat it to death and if I break it beyond repair it's going to the street to hand it down to another sucker.

But if you can help, I'm ready for it, Thanks

Click to expand...

I think you are trying to unlock two locking-taper shafts: https://en.wikipedia.org/wiki/Machine_taper#Morse

I have seen engines for sale advertised as "for generators" with tapered crankshaft ends. I don't know why this type of coupling is used unless for balance purposes as the armatures are pretty heavy. I also don't know how to unlock the two shafts in this case but I'm pretty sure it should have been done prior to breaking open the crankcase.

Good luck. Hope this steers you in the right direction.

On the end of the Rotor there should be a Bolt. Remove it & make up a suitable length of rod to fit inside. Us a suitable bolt to wind in as a puller, that's how I get my rotors off the crank shaft.

That is exactly my problem.

Every arm shaft I've looked at has a true BOLT, going all the way thru the hollow arm shaft, but not this generator. the others show a way of using a steel dowel or rod, with a short bolt to press on the crank shaft thus allowing the built up pressure to POP the arm shaft off..

It's made by Mecc Alte from Italy. It does not have a bolt that I can unscrew. It has a threaded bolt on each end, one end screwed into the crankshaft, the other end is not a bolt head. It's a nut and washer on a threaded end.

I can unscrew the nut and remove it but the bolt remains connected to the crankshaft. I believe this connection is causing the arm shaft not to move enough when it is hit to release. I cannot remove the bolt before the arm shaft come off.

I would take the long bolt on the end of the gen, loosen and swat that with a hammer that should get the armature off the end of the crankshaft. You may have to apply some pressure to the armature, similar to taking the flywheel off a Briggs engine.

Success!

The arm shaft came off this afternoon. I had gotten so frustrated with this project I was ready to trash the whole generator. I was going to give it one last attempt to remove the Arm Shaft. I set up the engine on the floor and took a stand. I held the 4lb dead blow hammer with both hands and hit the arm with all my might twice. I turned the arm 90 degrees and hit it two more two more times.
I didn't care anymore if I broke it or not but as I swung the hammer the fourth time the arm popped off and was held up by the bolt inside.
10 minutes later I had discovered the steel governor shaft was bent almost straight. No wonder the shaft spun 360 around in the engine.

This is probably the reason why I am the third or fourth owner of the generator since the previous owners gave it away after they tried to use it. The digital Hours gauge has 13.1 hours on it and the generator was made in 2006 date so sold by 2007, that would make it 10 years old with only 13 hours used.

I hope I have not bruised or broken the engine or generator after the new governor shaft arrives by UPS and install it. I just put the engine back together lightly to keep track of all the bolts from both devices.

To help anyone else I took a photo of the broken governor shaft and the bolt the was holding the arm shaft on.

I did remove some light rust on the crankshaft at the joint where the crankshaft and arm shaft joined together. that was why it didn't want to easily let go, because it had been sitting most of it's ten year life.

I'll post after the new part come in.

There was a lot of 14 HP Briggs engines on generator that were DC 115 volt and were used on viberaters for concrete. They weren't much good for any thing else so I pulled the armature off the motor and cut it apart and turned it down to 1.25 and put a key way in, them for another pulley and then it became a useful engine. I then bolted the adapter back on. Then you just needed a pulley that fit 1.25.

Kenny

Just a short note, Clean the tapers but do not grease, oil, or neva seize a taper it wont stay tight. I have a small machine shop I always store my tapered stuff oiled up but I carb clean it to put it together.
I also years ago took a techmusch engine and pulled the crank out of it and machined the taper to a straight shaft. It turned out to be like a 3/4 shaft but it was not that big of a engine.

Kenny

My new governor shaft arrived yesterday and just a few minutes ago I put everything back together, filled it up with a quart of new oil, added about a gallon of gas and let it sit for about two minutes.
I pulled on the started and on the second pull the engine started. With a little tweaking of the carb, the generator is running at 59-61 hz, and 119-121 volts using a "Killawatt Meter."

The engine sounds good and since the outfit only has now 13.5 hours of use I hope it will last as long as my primary backup generator which we bought in 1987 when we lived in Birmingham Alabama. It still runs and is 30 years old this year.

I was also given a old military generator. It's a Kohler 12hp 3.5kw. It was made around 1962 and with electric start it will be my go to generator.

Three generators living in hurricane area might be enough.

Thanks to everyone that helped me get through this. I was ready to trash the whole outfit.

Dont forget to fire each one up at least each year, more often is better and run something off the generator.
Down here is is generally bush fires than bring down power wires and I encourage customers to use their generators to power their shed / workshop thus they get used regularly.

I am glad you have it working, Heck I would not even know where to get parts for your engine. Now for the old military engine I would suspect that is is a 24 volt start, which means 2 12 volt batteries connected in series. Also in all likely hood there will be charging coils in the engine or does that one use the generator to start itself, some of the military stuff did not use an engine starter but used the exciter coil in the generator itself. That Kohler may have a regulator to control the 120 volt. If that engine has a 12 HP engine then in all likely hood its a 6000 watt or less. Generally a rule of thumb is 2 HP per kilowatt the old stuff was rated at what it was the new stuff will advertise as a 10,000 but will only be a 9500,
I have a 10,000 rated at 9600 and a 15000 PTO that rated at 15000, I can run the house with a 15K I have a water pump and electric water heater there are the big users, and a little load management and I can get along fine it uses approx 1/2 gallon /hour. AT our tractor club I ran 42 hours and used 20 gall of diesel.

Kenny at kkegris@yahoo.com

I see that the Kohler is a 3500 watt with that big a engine are you sure that its not a 3 phase unit, I know the military would go to the extremes when building things but that a lot of engine for a 12 HP it must be a heavy cause its i am sure is a cast iron Kohler.

Kenny kkegris@yahoo.com

The old Kohler engine is about 2 1/2 feet tall and a single cylinder.

It's as big as my 4 cylinder 1952 Ford 8N tractor motor.

It starts up fine, even though the whole generator has never been cleaned. It's got 50 years of grease and oil on it. It does spot a little but I can live with that.
I would like to clean it up some but I don't know where to start. I'm afraid of touching something that might break off and could not replace it part. It's got all sorts of, in my opinion, diodes looking things sticking out and wires going in and out of holes between the engine, the generator. the control box and the control panel. There is no, Wiring Harness on it. It really looks like it was put together out of old wiring parts.

But I tested it with a "Killawatt Meter" and it 120 volts and 60 cycles smooth.