Generator Clacking
My Onan 4kw generator has been making a clack, clack, clack noise since I purchased my motorhome in Jan, 2011. I didn't realize what a problem this was until the generator started cutting off after a...
Forum Discussion
From what I've been reading, theres quite a few of us going through this same problem, genset cutting off while going down the highway or once we stop while traveling for a short break.
It could very well be a heat issue causing the problem, because on ours in cool or cold weather, we never have a problem.
Now on holstein genset, it being a 2011 unit & 4000kw, I dont really know that type of engine, but I'm thinking it may be one with overhead valves & rocker arm, so holstein will need to check that & let us know.
On the other gensets, like say the 5.5 or 6.5kw, those engines are the type I call the old L head opposed cylinder twin, where the valves are in the block & just a flat head bolted on.
That design of engine, where the valves are located in the top part of the block & head is flat over top of the piston, its not uncommon for carbon to build up on the flat of the head & top of the piston & after a while the carbon will get thick enough, the carbon surfaces will start to contact each other & result in a knock or clack.
Briggs & Stratton, had an opposed twin cylinder mower engine just like the Onan & was recommended by Briggs to remove the heads & clean the carbon off the head & piston every 100 hours.
The Onan being of just about the same design as that Briggs, I would think would fall into the same type of cleaning process to prevent the knock or clack from the engine.
I can tell you this much, I have an old 18HP twin Briggs mower engine I bought back in the early 80s & a few years back came a slite knock in it & I just let it go. That knock got louder untill it sounded like it was going to blow up, so when I pulled the engine apart, one of the rods the rod bolts were backed out & that resulted from the carbon build up & it couldnt be compressed any further so something had to give up.
Seeing as I have heard, what an electric fuel pump sounds like before it is filled with fuel, would create a kind of light tin like clack if no fuel was in the pump, were as a carbon build up on the head & piston would cause a more deeper & louder type clack or knock.
As far as both those repairs that was made on holsteins genset, that could be chocked up to a lesson learned from it for him or either a letter sent to those repair places & a refund asked for, because all they did was take his money & the problem not corrected.
We RV folks, seem to be sitting ducks for places like that out on the highways, its just unbelievable how crooked they can be.
Neil
It could very well be a heat issue causing the problem, because on ours in cool or cold weather, we never have a problem.
Now on holstein genset, it being a 2011 unit & 4000kw, I dont really know that type of engine, but I'm thinking it may be one with overhead valves & rocker arm, so holstein will need to check that & let us know.
On the other gensets, like say the 5.5 or 6.5kw, those engines are the type I call the old L head opposed cylinder twin, where the valves are in the block & just a flat head bolted on.
That design of engine, where the valves are located in the top part of the block & head is flat over top of the piston, its not uncommon for carbon to build up on the flat of the head & top of the piston & after a while the carbon will get thick enough, the carbon surfaces will start to contact each other & result in a knock or clack.
Briggs & Stratton, had an opposed twin cylinder mower engine just like the Onan & was recommended by Briggs to remove the heads & clean the carbon off the head & piston every 100 hours.
The Onan being of just about the same design as that Briggs, I would think would fall into the same type of cleaning process to prevent the knock or clack from the engine.
I can tell you this much, I have an old 18HP twin Briggs mower engine I bought back in the early 80s & a few years back came a slite knock in it & I just let it go. That knock got louder untill it sounded like it was going to blow up, so when I pulled the engine apart, one of the rods the rod bolts were backed out & that resulted from the carbon build up & it couldnt be compressed any further so something had to give up.
Seeing as I have heard, what an electric fuel pump sounds like before it is filled with fuel, would create a kind of light tin like clack if no fuel was in the pump, were as a carbon build up on the head & piston would cause a more deeper & louder type clack or knock.
As far as both those repairs that was made on holsteins genset, that could be chocked up to a lesson learned from it for him or either a letter sent to those repair places & a refund asked for, because all they did was take his money & the problem not corrected.
We RV folks, seem to be sitting ducks for places like that out on the highways, its just unbelievable how crooked they can be.
Neil
