Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: George and Steph on May 30, 2016, 10:53:57 am

Title: Gen set thumping?
Post by: George and Steph on May 30, 2016, 10:53:57 am
Recently, after having steering box replaced, we are experiencing a decided thre bumps when it kicks in.  It did not do this before the replacement.  I have started it from the outside box and it does not appear to be from the engine nor does the tray move.  The front mounts appear to be good.  My friends Onan makes these at kick point but not near as loud.  Ideas?
Title: Re: Gen set thumping?
Post by: Pamela & Mike on May 30, 2016, 11:03:36 am
George,

Do you have the Isuzu 3LD1 power unit on your generator?
Did they roll the generator out to replace the steering gear?

Pamela & Mike
Title: Re: Gen set thumping?
Post by: Peter & Beth on May 30, 2016, 11:16:00 am
Tighten the bolts thet hold the genset tray very tightly.  All thumping goes away.  The tech likely pulled the genset out to do the work.
Title: Re: Gen set thumping?
Post by: George and Steph on May 30, 2016, 11:45:12 am
Yes that is the gen set and I will retighten the bolts...thanks.  I did not see movement on starting but I did not retighten either.
Title: Re: Gen set thumping?
Post by: P. Wyatt Sabourin on May 30, 2016, 04:36:23 pm
If tightening the tray bolts does not fix the thump, check the four rubber mounts which are between the generator frame and the drawer slide. Mine were disintegrated and causing metal/metal contact.
Title: Re: Gen set thumping?
Post by: George and Steph on June 01, 2016, 01:32:49 pm
Thanks all...it appears the tightening worked but there is significant deterioration of the back mount and some contact can be heard.  The thump was from the rear and I couldn't see movement of the tray. 
Title: Re: Gen set thumping?
Post by: Chuck & Jeannie on June 01, 2016, 02:18:51 pm
George,

Check this thread for a source for the correct mounts:

LORD #283P-155 Powertech Generator Plate vibration mount (http://www.foreforums.com/index.php?topic=26133.msg208558#msg208558)
Title: Re: Gen set thumping?
Post by: George and Steph on June 01, 2016, 02:46:39 pm
Thanks for the link!
Title: Re: Gen set thumping?
Post by: MAZ on June 01, 2016, 06:58:08 pm
Mounts

Isuzu Engine Mount (Green Dot) by Power Tech | Power Technology Southeast Inc (http://www.powertechgenerators.com/products/09mntgrn)
Title: Re: Gen set thumping?
Post by: George and Steph on June 01, 2016, 08:00:48 pm
Thanks Mark...when you separated your gen set what was the gap measurement you used?
Title: Re: Gen set thumping?
Post by: MAZ on June 02, 2016, 02:16:46 pm
Thanks Mark...when you separated your gen set what was the gap measurement you used?

I mounted the lower frame under the radiator to the deck with additional mounts like the engine rests on. Only after that did I cut the frame connecting the radiator to the engine. That allowed all the spacing to stay the same as original.

Mark
Title: Re: Gen set thumping?
Post by: George and Steph on June 02, 2016, 09:25:52 pm
I apologize for how I worded that Mark.  How much needs to be cut away so the two ends don't come into contact? 

George
Title: Re: Gen set thumping?
Post by: MAZ on June 07, 2016, 03:16:54 pm
I apologize for how I worded that Mark.  How much needs to be cut away so the two ends don't come into contact? 

George
Sorry. I just cut maybe 1/4 inch out or so. I could measure if you want.

Mark
Title: Re: Gen set thumping?
Post by: George and Steph on June 08, 2016, 07:25:09 pm
Went out and looked and 1/4 to 3/8 looks good.  Thanks for getting back to me.  Located a lift and having at it next week.  The mounts, tape, insulation, etc have all come in now.  Your documenting of the process is so helpful.  Been referring to it as the MAZ method.