Replacement engine for Colemate Generator

Have you actually checked on a replacement engine or shortblock from Tulsa Small Engines or Small engine Warehouse? A lot of times they have these engines for less than the price of dirt.

I have seen one ingenious individual salvage a gen set that had a severely scored connecting rod journnal and piston. He removed the piston and con rod, and bolted a section of the con rod on to the crank shaft so it still had a slinger, removed giovernor and valve train, and installed a pulley n the magneto side of the flywheel which he drove with another common horizontal gas engine by way of a V belt. It worked and worked fine, was a bit cumbersome when it came to moving aorund but it provided power and all it cost him was time. He had comtemplated making a plate with a bearing for the gen front support but there was very little in the wya of shaft to work with an this was his easiest way out. The internally stripped engine on this gen set functioned mainly as a bearing support and driveline component.

The majority of all gen sets use a very short taper on the end of the engines crank, so its not a odd ball setup. Visit my website:

expressed are those of my wifes, I had no input whatsoever. Remove "nospam" from email addy.

Thanks for the tip. A local supply house wanted $600. The Tulsa Small Enignes and Small Engine Wareshouse were both a little over $400. I'll have to keep them in mind for future buys.

The orignal block casting was badly damaged so I won't be able to use it for bearing support.

If I make a new shaft and bearing. The bearing will need to carry some axial load and hold the armature in postion. This would make it easy to do a simple test to make sure the generator if fully functioning. Any suggestions on bearing type?

If I go with an an adapter to mount direct to the 6.6hp engine no addtionl bearing would be needed but I won't know until it is done if the generator is really good.

Bob

On 18 Jul 2004 20:52:56 -0700, snipped-for-privacy@yahoo.com (Robert Snyder) vaguely proposed a theory ......and in reply I say!:

remove ns from my header address to reply via email

Learn the same lesson before trying this with firefighting pumps as well....close-coupled, and the emgine may cost _more_ than the pump, new.

Don't know where you are, but check out princess auto in Canada -

they have some Coleman generator engines as surplus in their monthly flier this month.

May be worth it to have it shipped/picked up - IIRC $350 CDN for 11hp

Tom

I checked princessauto.comm and the engine looks very good. I am concerned it would not be an exact match for proper fitup.

I am going the route of a seperate engine and will be making a new shaft with bearing support. I can then add an enigne with belt drive.

I have seen an example on

I am not sure if you can drive a generator opposite. The orignal setup rotated the generator CW when direct coupled. If I go the the belt drive, with the generator up,the generator would rotate CCW. I could put the generator down and get CW if needed.

Bob

Don't know if the original crankshaft is still okay? You stated that the block was shot and that you wouldn't be able to use it for support, but what about cutting off the crank a short distance from the gen face, then installing a bearing plate for support, and use like a lovejoy coupling from your new engine shaft to the remaining part of the crankshaft from your old engine. This would still keep it fairly close coupled. Ken.

Bob -

regarding : Capacitor: 200uf 330vac. This was made by paralleling 4 capacitors that were

65uf, 35uf, 50uf and 50uf. All of these were rated at 330vac or better. All test results are from this capacitor set. (NOTE: The final version of this generator has 225uf of capacitance.)

From the web - remember that series caps do not add - 1/ct = 1/c1 + 1/c2 + 1/c3

• 1/c4 Quick rule of thumb - smaller than the smallest.

Best Regards, Mart> I checked princessauto.comm and the engine looks very good. I am

Robert: There are times when resourcefulness and creative engineering can save you a lot of money - and trust me on this Bubbie ;-) this is NOT one of those times.

If you are driving a generator and need the output to be fairly stable at 60 Hz, you will need an engine with a tight governor control on it. The small gasoline motors made for generator applications have the flyweight governors needed to hold 3600 RPM on the nose already built into the crankcase, and the throttle linkage pre-engineered and factory installed - and regular lawnmower engines only have an air-vane governor in the cooling air behind the flywheel, providing very rough speed control that will surge and hunt all over the place. And the output voltage is going to surge and dip like crazy along with the engine, making the power useless for anything halfway sensitive.

If you use a general purpose engine, you will need to buy a separate flyweight governor or an electronic governor system, and then devise a decent throttle linkage for them. Both most likely to turn out much more expensive and a lot more work than just finding or buying the right engine in the first place.

I had to buy a replacement flyweight governor for my old 10KW Signal Corps generator, and that was $150+ 15 years ago. They haven't gotten any cheaper. And that was for a flathead 'MB' Jeep engine that had a V-belt pulley to drive the governor already - most small Briggs engines have no access to the crank nose for a pulley, they put the recoil starter there.

That probably won't work either. The engine rear bearing is either ball bearing or sleeve bearing, and is designed to be running in an oil bath and part of a pair to handle thrust loads. And it certainly wont like overhung (pulley driven) loads.

Save yourself a whole lot of grief. Go get the right engine, with the right governor and the right output shaft size and taper, and close couple it to the existing generator. And it's DONE.

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Take the tapered crank out of the engine and cut it off... leave all the shaft that you can... Now cut off the back face plate off the engine... Slide the crank back in the gen. and bolt the face plate back onto the gen. Now you got a gen. with a side shaft... Works great...

Update-

My project is proceeding at a snails pace do to it being summer. However, I have made the replacement shaft made except for the final pulley end diameter. Also, I made a bearing holder (bearing is a 20mm ID) and have the bearing installed.

I stopped by a motor shop in town and talked with the owner. He said my generator being an older brush type should work either direction. He also told me he doesn't like the direct drive engine generator and was interested in how the project comes out. My first test was a simple spin by hand and the output voltage could be detected in either direction. I next tested by connecting the generator to a small 1750 rpm motor. The generator output showed about 60+ volts ac at the 120 plug and 120+ volts ac on the 220 volt. Once I get it up to full speed it should be good to go. These 1750 rpm tests were CCW which is opposite of the original rotation.

I am planning on 3/4" diameter for the generator pulley shaft. I am checking on avaiable pulley sizes first.

For the frame to hold the generator and engine I am thinking of some combination of light angle and bar (perhaps some plywood) I want to keep the weight down. I have used plywood on some other motor mounting projects and it seems to be fine for light duty ie wood bandsaw 3/4 motor. I made a base for an air compressor motor using angle and plate and it is heavy. I may look for some 10 gauge sheet and light 2" angle. Any votes for plywood?

Bob

Update -

I got the generator and engine working together.

I am using an old Toro engine with a standard aluminum flywheel and an external flywheel (metal disc about 9" od x 1.4 inch thick) The generator inertia really adds alot.

The engine pulley is 4.5 inch and the generator has a 4"

First run - about an hour of testing probably about 20 minutes running.

I let the engine warm up and adjusted the engine speed with a 1500 watt heater connected to give 120 volt. I was able to start a 3/4HP motor with the 1500 watt heater running. I made some adjustments with difffernt hookups to see what works the best. I noticed if I run the heater at 750 watt and set the volatge to 120v the engine seems to hold better when load is added. The worst volatge drop observed was setting the no load engine speed to produce 120 v and then starting the 3/4 hp motor.

I am working to improve the engine and generator mount. The setup is with a belt drive and I need more adjustment.

Any simple tips on how to improve speed control? I may experiment with a lower watt base load.

This has been a fun project. I should be able to run the house water pump during a power outage and a few items like lights and refrigerator.

If anyone has an old Coleman generator with the orignal engine I would be interested in what type of voltage swing occurs.

Thanks,

Bob

65uf, 35uf, 50uf and 50uf. All of these were rated at

final version of this generator has 225uf of capacitance.)