1983 MTD Products portable generator - need help please

[RoyM]

With a five hp engine it likely puts out around 2,000 watts. Normally the no load speed would be set at 3,750 rpm, under load it should maintain 3,600 rpm to produce 60 hz. Electric motors don't survive well on less.

[Arkie]

I'm just kinda winging it here with your info.

Being a 5hp I would guess that it's probably around 1800-2000 watts.
Does it have only 120v recepts, NO 240 recept?

Sounds like it doing well. I would let it run with a light load of 600-1000 watts for awhile.
Being a 5hp it would mainly be used for emergency lighting and they make a real good camping gen and will operate a regular size refrig or freezer in a emergency, one at a time, and a camper window type A/C up to about 5-8000BTU's

Sometimes they will have kw rating labeled somewhere around the recepts, or some type of max warnings.

To get more precise instead of using engine rpm's and a tachometer, a Hertz meter (HZ) or frequency meter that will read 55-65 Hz.
Normal utility power is 60 cps (cycles per second) or 60 Hz (Hertz) Hertz and cps is same thing.

With a hertz meter you would set the no load Hz at about 62-63 and at 80% of rated KW (kilowatt load) One KW is 1000 watts)so if the gen is a 1800w unit (1.8KW)is 1440 watts or about 12 amp, 120 volt resistance load. (a electric heater) it may dip and stay at around 58Hz, so you are averaging around 60Hz loaded and no load. The large spring associated with the governor lever is to set the gov sensitivity for minimum hunting from load to no load. If it don't have auto idle you can set the idle adjust screw in to prevent a low dip when it loads up initially until the governor picks up the load and reduce the hunting dip in Hz somewhat.
Those small gen''s will really struggle when trying to do a motor load, because when a electric motor or electric compressor first starts it draws about 6 times it's name[plate current when it first starts, therefore when checking the samll emergency gen on a appliance like a fridge or window A/C you have to be careful and not overload the gen.

You are blessed that it did not have the obselete Tecumseh engine.

Do not be surprised if you check and find some of the Briggs parts such as the SPECIAL crankshaft is NLA.



Did you have to excite the unit and does it have any circuit breakers or fuses on the gen?

Post up a picture of the rig?

Some of the $20 wal mart electrical testers will read in the 60 Hz range. Some use a Kill-O-watt meter at about $20.
You read the owners manual on-line and see them on flea bay. If you use a KIll-o-watt meter use a extension cord for the tester so as it don't have to ride on the vibrating genny chassis.

[creia]

Thank you both for your replies and continued support!
We have the engine running very well, the governor is not surging, and the engine rpms maintain steady.
It turned out that I did NOT have to "flash" or "excite" the generator! When I first tested/ran it, it did not power my drill or lamp because it was only putting out 80V due to the governor and fixed speed control knob being out of adjustment.(I checked this with my meter after)
It does have a fuse- 15A which is accessed by unscrewing a small plastic cap. (However, I do not know if that fuse is the correct rating for this generator?)
It has only (2) 120V receptacles- no 240V
If I raise the no-load" rpms to 3,750 I think that it will very likely raise the voltage even higher than the (already elevated) 130V- is that a problem?
Can you provide a link to an adequate (and reasonably priced?) hertz meter? Keep in mind my son and I are garage mechanics and this is the first and only generator we may ever have. (yes, I am a cheapskate at times)
As far as posting some photos- no problem, however, I am a computer ignoramus. I will have my son do it who is my IT support and MUCH more computer-savy than me.
Michael

[Skywatcher]

Hi Creia

Glad to hear you got the old gen-set producing power. For a low cost frequency meter, I've read members post about a gadget called a Kill-o-Watt, it plugs directly into the 110 volt outlet. As for frequency, 62Hz (3,720 rpm) is a good no-load setting which should give you 60Hz at 75% rated load taking governor drop into consideration. Normal figuring for generator power is about 1½ horsepower per Kw. All the best,

Sky

[Arkie]

Read my above post about the kill-o-watt on flea bay that Sky mentions. (and using it on a extension cord)

Do not raise the rpm's to 3750 just yet.

Eventually get a Hz meter and if the unit is working good as it is now at 58-62 hz just leave it be.

Using a tach on a gen can result in the voltages going too high and is not as precise for electrical set-up of a gen.. 135 volts is getting at the upper range.

If the unit has a 15 amp fuse it's most likely correct. Your gen is probably rated at 15 amp fuse x 120 volts or 1.8800watts or around 2KW, BUT a good ball park figure is use 12amp as very max continuous loading or around 1440-1500 watts resistive loads.

Fuses or breakers are actually rated to carry only a 80% continuous load.

Also do not try to operate any electronics, such as a tv from YOUR gen, they won't like each other.























.

[creia]

Thank you all for the education you have provided- I am learning!
Hopefully, my ignoramus questions will help others with their first generator.
I just ordered a Kill-A-Watt on eBay. I'll report back after I have had a chance to set up the generator with it.
Until then,
Michael

[creia]

OK, I hooked up my new "Kill-A-Watt" monitor, and after dialing in the generator speed here is some initial test data:

Hz Volts RPM
No load 61 131 3,700

730W load 60.5 122 3,640

1250W load 60 111 3,600

I believe that it is et up about right based on your previous comments. What does everyone think?
Thanks again for the help,
Michael

[Arkie]

OK, I hooked up my new "Kill-A-Watt" monitor, and after dialing in the generator speed here is some initial test data:

Hz Volts RPM
No load 61 131 3,700

730W load 60.5 122 3,640

1250W load 60 111 3,600

I believe that it is et up about right based on your previous comments. What does everyone think?
Thanks again for the help,
Michael

[b]You got it.[/b]

Not exercising a gen every once in awhile is their enemy. I must confess I do not run mine monthly as suggested by most.

I operate my small portable emergency gen's about twice a year. I do always use non-ethanol gas and when I store mine I flood the carb with ATF fluid in the bowl and if metal gas tank the ATF is mixed with little bit of gas in the tank. (trying to keep corrosion from starting in the gas tank)

The electric start gasoline RV Onan get's operated under load about every 3 mo's.

I have a 7.5kw that is tri-fuel converted and I exercise it on propane every once in awhile. Do not have to be concerned about gasoline going bad in the carb during storage when exercised on propane.

[Arkie]

If I have not mentioned this one, you need to eventually check the bearing on the output end of the rotor, the bearing that fits into the end bell. Usually it remains on the end of the rotor when the end bell is wiggled off, but may stay in the end bell. Usually easily removed if it appears dry and just use the ID numbers from the bearing's seal for replacement. If it's still smooth but appears dry of lube and has the plastic side seal just use a o ring pick and gently pop the seal out re-pack with EP-2 grease and re-install the seal. The plastic type side seal will pop on and off easily with care.

Make sure that the bearing spins smooth and don't indicate it's dry of grease.If it get dry or noisy it will eventually seize and it's race will start spinning in the end bell and ruin the end bell.
AND a end bell replacement is sometimes hard to locate.

AND make sure that the center rotor bolt is snug tight that holds the rotor to the engine.

[creia]

Arkie,
Thank you for the information on lubing the bearing in the end bell. Looking at the end of my generator, I see a bolt in the center (That must be the "center
rotor bolt" you are referring to?) and also 4 bolts around the perimeter of the end bell. (My end bell is square so there is one bolt at each corner) So... to remove the end bell to check, lube, or replace the bearing do I need to remove the center bolt AND all 4 perimeter bolts? Does the end bell just pull off easily? After I pull it off, will anything else inside possibly come loose that I do not want to come loose? On this generator, the (2)110V receptacles are mounted on the end of the end bell, so when I remove it I will have wiring to deal with as well. Please forgive the ignoramus questions I am just starting to learn about these generators.
Michael