Journey with Confidence RV GPS App RV Trip Planner RV LIFE Campground Reviews RV Maintenance Take a Speed Test Free 7 Day Trial ×
RV Trip Planning Discussions

Go Back   iRV2 Forums > RV SYSTEMS AND TECHNOLOGIES FORUMS > RV Systems & Appliances
Click Here to Login
Join iRV2 Today

Mission Statement: Supporting thoughtful exchange of knowledge, values and experience among RV enthusiasts.
Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on iRV2
 
Thread Tools Search this Thread Display Modes
 
Old 07-01-2014, 07:26 PM   #1
Member
 
Join Date: Dec 2011
Posts: 34
Generac generator issues

I need some help with my genset. I have a 2006 Damon Astoria 40 ft diesel Class A which I bought about 2 1/2 years ago. The genset is a Generac Guardian 75D model 4270 diesel 7500 kw unit. Has about 1100 hours on the unit. I do my own maintenance and am pretty fastidious about it. I do a lot of my own mechanical work and do not hesitate to tackle larger jobs, but the older I get the more I am thinking of paying for good work rather than doing it myself.

I do not recall having any issues with it until this year, when my kids could not pop popcorn in the microwave going down the road, and the coach A/C seemed not up to par when on the genset.

Bought a plug in Kill A Watt meter. Genset fires up fine, and with no load I am seeing 125 V and 62 Hz, which is excellent. When I add a load (Microwave only) I am seeing voltage drop to 105 V and cycles drop to 40 Hz. Engine RPM's seem constant even after adding a load, but that might be a feature of this genset.....

Here are some of the problems- there is no Generac service folks in the area (Eastern Iowa), the RV service center listed on the Generac web site won't service them. I called the Cummins shop (manufactures Onan gensets), and asked them nicely, "Money is money...." would they consider working on a Generac and they said unequivocally "NO".

I have downloaded and looked through both the Owners Manual and Diagnostic Repair manual for this genset. Nothing too specific on this situation, possibly the control board. Not much on a Google search either.

My thought at present - Get underneath the unit, and first do the usual maintenance to make sure everything is fresh. Will also replace the genset drivebelt. Next thought is to buy a new engine circuit board ($280) and consider a new voltage regulator ($170) and throw those into the unit myself. Should be able to do both without removing the genset....(it is not on a slide...)

If those maneuvers DON'T work, then I might be looking at either 1) travelling to have someone look at it (time and $$$), or 2) DIY swap out for a new genset - likely an Onan, but I guess at that point I could let the Cummins shop do that, but I would likely be looking at $9-10,000 for a new genset........

Any thoughts and suggestions would be appreciated....
Plastx is offline   Reply With Quote
Join the #1 RV Forum Today - It's Totally Free!

iRV2.com RV Community - Are you about to start a new improvement on your RV or need some help with some maintenance? Do you need advice on what products to buy? Or maybe you can give others some advice? No matter where you fit in you'll find that iRV2 is a great community to join. Best of all it's totally FREE!

You are currently viewing our boards as a guest so you have limited access to our community. Please take the time to register and you will gain a lot of great new features including; the ability to participate in discussions, network with other RV owners, see fewer ads, upload photographs, create an RV blog, send private messages and so much, much more!

Old 07-02-2014, 04:58 AM   #2
Senior Member
 
94-Newmar's Avatar
 
Join Date: Nov 2009
Posts: 2,043
Your no load voltage and HZ are ok at 125VAC and 62HZ - voltage regulator is fine.

This unit is a fixed rpm unit (not inverter based), therefore the rpm will not change with load and the HZ is based solely upon rotor speed. Your loss of HZ is relevant to generator rotor speed. The voltage regulator has absolutely no affect on the HZ output, only voltage.

When voltage and HZ drop equally with applied loads it's always 1 of 3 things:

(1) The drive belt is stretched beyond usability and slipping allowing the rotor speed to drop below engine rpm.
(2) The drive belt tensioner is galled & frozen in place or the bushing has failed and is and unable to keep proper tension on the drive belt allowing it to slip thus causing rotor speed to drop below engine rpm.
(3) The governor control has failed. If you cannot hear the engine change several hundred RPM as you apply loads then the governor is ok.

My bet would be on 1 or 2.
__________________
94-Newmar Kountry Star 40-KSDP
Spartan/Cummins 8.3C-300HP/Allison 3060 WTEC-II/25yr RV Tech RVIA Certified/Onan-Cummins Certified
94-Newmar is offline   Reply With Quote
Old 07-02-2014, 01:40 PM   #3
Member
 
Join Date: Dec 2011
Posts: 34
94-Newmar - I can't thank you enough for pointing me in the right direction. I will try to get to work on it this holiday weekend. As I mentioned, I will be replacing the drivebelt, and your reasoning sounds dead on. While replacing the drive belt I will closely inspect the belt tensioner. Thanks....

Will wait on these results prior to sending out for a new control panel, and I won't even think voltage regulator. Likely saved me about $500 if this solves my problem
Plastx is offline   Reply With Quote
Old 07-04-2014, 07:27 AM   #4
Member
 
Join Date: Dec 2011
Posts: 34
Yesterday I started pulling panels off my Generac 75D. Much tougher to do this work when the genset is not on a slide.

The drive belt and flywheel are on the passenger side, and that panel looks to be up against a structural member. Will take a closer look today to see if I can remove this piece.

Took off the front panel where the flywheel is seen on edge toward the front. The drive belt appears fine, but the tensioner, as you indicated in #2, is pulled slightly away from the belt and spins freely. Without the ability to look at the situation directly, the problem then lies in the tensioner or the 4.5" tensioner pulley.

Will order all replacement parts, then see if I can't do the replacement without having to drop the generator. If I can't do it without dropping it, might just spend the $$$ to have someone else do the job, maybe in Elkhart.....
Plastx is offline   Reply With Quote
Old 07-04-2014, 02:42 PM   #5
Member
 
Join Date: Dec 2011
Posts: 34
Looked again. There is no way to replace drive belt and tensioner without dropping the unit out of the front , and at 450# I am not sure I want to tackle that. I will likely talk to a truck service center that I use frequently about that.

While it is down out of the front I also intend to replace the fan belt and it's tensioner also.

Are there any other parts I should replace such as oil switches or spark plugs (diesel genset) while it is out of the vehicle?
Plastx is offline   Reply With Quote
Old 07-04-2014, 09:08 PM   #6
Senior Member
 
Rexhall Owners Group
Join Date: Jul 2008
Posts: 135
I'd replace any/all maintenance items (belts, hoses, filters), maybe have the radiator inspected too. The oil and temp switches might be a good idea as they can't be replaced with the gen in the coach either. No spark plugs in a diesel. How is your starter? I have the same unit as yours and I seem to eat starters and while they can be replaced while in the coach, it is easier when removed.
JohnInAz is offline   Reply With Quote
Reply

Tags
generator



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Rexhall Generac problem. Advice please. Dieselpusher MH-General Discussions & Problems 21 05-29-2014 06:40 PM
Generac NP50G tarphenry RV Systems & Appliances 1 03-12-2014 05:50 AM
Generac has no a/c output Shacker RV Systems & Appliances 6 02-12-2014 09:03 PM
Generac no workie pckncmt RV Systems & Appliances 4 12-03-2013 02:25 PM
Generac Primepact 50G Generator burning up ignition coils??? RD350 RV Systems & Appliances 9 06-11-2013 06:44 PM

» Featured Campgrounds

Reviews provided by


All times are GMT -6. The time now is 06:05 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.