Kohler Gen Set - Reduced Volts

OK - Here's the circumstance... regarding our 34' 1977 Tolly tri - 7.5 Kohler generator

I have two Kohler service shops trying to locate parts for our [what I believe is the original] 1977 Kohler Gen Set.

I also contacted Kohler HQ. They put me in touch with their primary parts distributor... boatswainlocker.com. One of their parts persons is trying to make heads or tails of this situation and if parts can be located.

Long and the short of what is happening:

So far no one can make heads or tails about the numbers on the plate on our Kohler gen set. One of the service shops could only locate that it may be an RV gen set (Boatswain Locker's person kind of agreed it had RV background from running numbers off the plate. The Boatswain Locker person is now searching all avenues at Kohler HQ in attempt to locate parts for this gen set.

To let you know why I seek parts: The gasoline motor of the gen set is in fine running condition. However - the electricity generating portion has a progressive problem - it continues to loose voltage production capability. In that... it now only turns out +/- 105 volts. Circumstance that occurred when the voltage got this low was the gen set could still run all electric appliances on our boat [fully electric boat] but the 105V output can no longer activate the house bank battery charger. The batt charger turns out 13.5 to 14.5 amps on shore power but only .5 to 1 amp on gen set power [while on gen set it used to do same as shore power]. I've checked this carefully by utilizing an exact same type of charger [I have a spare] and got same difference in amperage capability per shore power compared to gen set power.

One smart person mentioned that the reason the plate #'s lead toward RV gen set avenues is due to PO having replaced the electric generating portion with similar unit from an RV Kohler gen set??? Pretty good guess if you ask me! But, so far still unable to locate rebuild parts for the electric generating portion.

Photos here are the gen set and its plate. If anyone has input regarding this dilemma of what I have for gen set units and a way to locate parts availability... It Would be Much Appreciated!

Happy Gen Set Daze! - Thanks! - Art

I rather have a different view of the problem. I would ask, who has service information. Inside that, you will find a system that has various lockouts and field/rotor current controls that have various connections and dependancies. Do you know you have a defective part? Is the engine running at 1800 rpm +/- 50?

Can you tell I'm an engineer?

Yep, check rpm or Hz. Some of these make low volts if governor speed setting is low.

Seems / sounds to be turning same rpm as it has been doing so during last 10 years. Have not yet run rpm gauge on it.


Recently was told by a parts supplier that could be something as simple as the regulator - $200 +/-. Also told that stator and other interior parts would be next to impossible to locate as well as would cost in the $700 dollar range.


I'm not clear on what part is the problem that is making the voltage output drop. Still waiting for more input from Kohler service persons I have on the case.


I appreciate your input.

Try calling Broward Armature in Ft Lauderdale. If it has anything to do with marine gen sets, they WILL know.
954-583-9888

High Wire said:

Try calling Broward Armature in Ft Lauderdale. If it has anything to do with marine gen sets, they WILL know.
954-583-9888

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Thanks Archie

I called and spoke in-depth with "Mike". Possibilities for sure. I may use them depending on items as they evolve on this end. Full restoration of the gen set's "back end" [the electricity production portion] could go into the $3.75K range - plus shipping... if lesser problems exist... could be under $1K. for them to repair it.

I'm still hoping that the back end is OK in general and there is a simpler solution for getting the voltage reading back up. Currently waiting for return call from Kohler generator service expert in area where we dock.

In addition to my general mechanic's eyes/smarts that already looked at the gen set... it will be good to have an expert service technician to provide his take on items at hand.

Your voltage is directly related to the rpm. It is either running slow because of a high load or dirty fuel filter, poor/old gasoline or the speed screw has vibrated out. Bring the engine rpm up to the point you have the correct voltage.

Art said:

Seems / sounds to be turning same rpm as it has been doing so during last 10 years. Have not yet run rpm gauge on it.

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It doesn't take much of an rpm difference to reduce voltage by 10 volts. I doubt you could "hear" that from memory. I know I could not. You should try to either turn up the speed a bit or check engine rpm.

listen to the above advice.

RPM and load capacity are directly related. before replacing parts measure the line frequency under load when the voltage is low. RPM and Hz are exactly related. 60HTZ equals precisely 3600 or 1800 rpm depending on design. You can measure either RPM or Hz what ever meter you have at hand. It is not possible for RPM to be correct and Hz to be wrong.

Does the voltage recover when the load is removed???

I looked up the unit. It is a marine unit from the git-go. Looks to have an electronic voltage regulator. But many of the AVR's are speed sensitive. So if rpms are low, volts may be low too with the whole electrical end otherwise doing as it should.

Check the rpm/Hz before doing anything else.

My brother spent a chunk of money to have his Westerbeke rewound by Broward Armature about 18 months ago. He said they were great to work with and I know that they are generally considered to be the best in the business, very honest and through.

His gen-set lasted less than a year after he got it back, the end failed again after 145 hours. He called BA up, and they told him there was nothing they could do other than another rewind. Offered him a small discount.

He ended up buying a whole new genset.

Point of this is not to throw shade on Broward Armature but to think long and hard before you spend money to try to repair a 40 year old generator.

Greg and Jay -

I'm moving forward with many thoughts in process for alleviating this voltage drop condition. Thanks for input.

Appears it will be Monday before I get chance to chat with a Kohler gen set expert who has business close to where we dock. Planning to try and get him to visit boat for personal review. Will mention to him all I've recently learned in hopes that a solution soon becomes available.

Unfortunately due to needs at hand I've currently no time to do the 100 mile trip to the boat... otherwise I'd be ahole and elbows into trying some of the suggestions!


Cheers! and Merry Christmas!! - Art

BV, Ski, Doug... Thanks for all your input. I'm listening closely and taking notes! - Art

Art said:

BV, Ski, Doug... Thanks for all your input. I'm listening closely and taking notes! - Art

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Listen closely to that rpm. It sounds like about 1710 rpm.

or maybe check with a cheap portable tach.

Yes.... check HZ and/or Voltage FIRST.

Meanwhile, do not run anything you don't want to replace on that low a voltage.......

oscar said:

Yes.... check HZ and/or Voltage FIRST.

Meanwhile, do not run anything you don't want to replace on that low a voltage.......

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Understood. Thanks!

https://www.smokstak.com/forum/forumdisplay.php?f=25

Lots of good people on this Kohler forum might be helpful

I know my Onan must spin fast enough or the volts and HZ drops.
Many voltrmeters have a hz reading, check what yours is.
I found I have to raise my rpm slightly to get it to produce well under load, so might be 62 hz unloaded, but 59 to 60 loaded. HZ and volts are tightly bound to gen rpm.

sdowney717 said:

https://www.smokstak.com/forum/forumdisplay.php?f=25

Lots of good people on this Kohler forum might be helpful

I know my Onan must spin fast enough or the volts and HZ drops.
Many voltrmeters have a hz reading, check what yours is.
I found I have to raise my rpm slightly to get it to produce well under load, so might be 62 hz unloaded, but 59 to 60 loaded. HZ and volts are tightly bound to gen rpm.

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Thanks sd! I'll review and likely post - Art


Edit: Yup... I joined smokestack. Waiting for admin approval. Seems like a cool forum with potentially a plethora of answers/insights for all sorts engines and thangs!


Thanks again sd... this is first time I paid attention to that forum.


Enjoy your 1970 Egg!

Art,
looking at the parts book i found online.
http://www.wanderlodgeownersgroup.com/downloads/Generator/Kohler_7_5Gas_TP5045.pdf

your gen uses brushes and a avr. the unit is producing the 105vac. so more than likely the gen end and avr is ok. normally when ether component has failed it will ether make too much voltage or not make any. you will want to check your running hz as posted above before going any further.

BIG CAT said:

Art,
looking at the parts book i found online.
http://www.wanderlodgeownersgroup.com/downloads/Generator/Kohler_7_5Gas_TP5045.pdf

your gen uses brushes and a avr. the unit is producing the 105vac. so more than likely the gen end and avr is ok. normally when ether component has failed it will ether make too much voltage or not make any. you will want to check your running hz as posted above before going any further.

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Thanks, BC - That is my plan!

Ski in NC said:

Yep, check rpm or Hz. Some of these make low volts if governor speed setting is low.

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You REALLY need to heed Skis advice on this one.

Get a good quality hand held voltmeter with HZ capability.

Most voltage regulators in genberator ends are VERY frequency sensitive.

If frequency is not your problem, more than likely your voltage regulator is the issue. There is often an adjustment on these.

ksanders said:

You REALLY need to heed Skis advice on this one.

Get a good quality hand held voltmeter with HZ capability.

Most voltage regulators in genberator ends are VERY frequency sensitive.

If frequency is not your problem, more than likely your voltage regulator is the issue. There is often an adjustment on these.

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Yup! As I'm 100 miles from the boat... Next week plan to get a technician to follow that direction. Thanks!! - Art

Think we have the same genset, Art. These guys have a good inventory of NOS Kohler parts and a good bit of knowledge about these units:

Jim or Hob Bonnett
Wavetop Technology Inc
New Bern, NC
Office 252-636-0715 M-F 9-4
Cell 252-626-5388
http://www.wavetop.com/prod-kohler-parts.htm

sbu22 said:

Think we have the same genset, Art. These guys have a good inventory of NOS Kohler parts and a good bit of knowledge about these units:

Jim or Hob Bonnett
Wavetop Technology Inc
New Bern, NC
Office 252-636-0715 M-F 9-4
Cell 252-626-5388
http://www.wavetop.com/prod-kohler-parts.htm

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Thanks, sb! I opened the link. Looks like really good Kohler parts opportunity, general input too. Will contact them. - Cheers! Art

PS: If yours too is gas engine... is there hour meter on yours? Not on mine... just wondering how long these baby's run. So far [during 10 yr. ownership]the engine is perfect. We don't put too many hrs. on it. Don't think the PO [original] owner did either. The more I get into this the more I am feeling the low voltage problem will get cleared up.

Art me Irish Gen-less Bro.

Stop being so bloody cheap and buy a new or slightly used Gen Mate. You have got your use out of your 1,000 year old the bloody Gen. It is time to let the Mate go! Let it go!

The time and $ you are spending or will be spending, along with the stress is not worth it Mate. You can have a new Gen in place by time you get parts of get the Gen fixed Mate.

So pick up the phone. Buy a new Gen and slap the puppy in and that new puppy will be your friend. I know it is hard to let go of an old friend. But it's Time!

Cheers Art and I Irish you and yours Merry Christmas

H.

hfoster said:

Art me Irish Gen-less Bro.

Stop being so bloody cheap and buy a new or slightly used Gen Mate. You have got your use out of your 1,000 year old the bloody Gen. It is time to let the Mate go! Let it go!

The time and $ you are spending or will be spending, along with the stress is not worth it Mate. You can have a new Gen in place by time you get parts of get the Gen fixed Mate.

So pick up the phone. Buy a new Gen and slap the puppy in and that new puppy will be your friend. I know it is hard to let go of an old friend. But it's Time!

Cheers Art and I Irish you and yours Merry Christmas

H.

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Worry not my boxen Irish friend!

I'll not put too much $$ into this ol' baby.

So far just couple hundred $$ expense for others checking things out and couple hrs. time of me on keyboard and ph.... whilst I conduct other work efforts. Long and short of it seems to be coming down to simply more gen set RPM and more Hertz. Cheap at 1/2 the price in my estimation!

I'm learning all the time on this occasion. If expense gets to climbing too much... then the whole kit n' caboodle will be used as a mooring weight.

Merry Christmas - You Large Sized Smilen Leprechaun!!

Btw I keep a KillAWatt monitor plugged into a handy outlet to monitor gen voltage and frequency. Excellent and only about $30.

Art said:

Yup! As I'm 100 miles from the boat... Next week plan to get a technician to follow that direction. Thanks!! - Art

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You don't need a tech to do this. Go buy either a meter with a Hz setting, or go to Harbor Freight and buy a phototach for like 40 bucks. Either will tell you if it is running slow.

Either will be way cheaper than getting a tech to do it. And the tools will be useful for as long as you own the boat.

You have spent more time typing about this than it would take to check speed!!!

Ski in NC said:

You don't need a tech to do this. Go buy either a meter with a Hz setting, or go to Harbor Freight and buy a phototach for like 40 bucks. Either will tell you if it is running slow.

Either will be way cheaper than getting a tech to do it. And the tools will be useful for as long as you own the boat.

You have spent more time typing about this than it would take to check speed!!!

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Ski - Agreed. I plan to purchase those tools for aboard boat future conditions. Unfortunately, currently I've not the time to travel 200 mile round trip just to visit the boat to check out Kohler generator RPM / Hertz. Relatively small cost to have a gen set "smart" person do my needs for me is best alternative to learn more and have persons in that area for future needs if required.