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Onan 5500 Issues

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No I haven't yet. It's been raining today and the park discourages working on your unit. They allow technicians in the park.

I have sea foam on my "to buy " list for today, and I have another tech certified in Onan generators coming by the first part of the week. My conversation with the 2nd tech was encouraging when he said....

"listen to me, why do you want to pull out your generator?" 

That sounds right to me

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I've got my sea foam in hand. How would you advocate I apply it? Separate fuel tank and hose to the gen set? 50/50 mixture with fuel? 

They didn't have the spray so I have the 16oz additive can.

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I had a 5 gal gas can and added a rich mix (more than the minimum on the label) of the seafoam. That way you don't have to treat the whole tank in the coach. The last time I did this I ran for about an hour with no load then started to add load.

Bill

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15 hours ago, WILDEBILL308 said:

I had a 5 gal gas can and added a rich mix (more than the minimum on the label) of the seafoam. That way you don't have to treat the whole tank in the coach. The last time I did this I ran for about an hour with no load then started to add load.

Bill

Wow,

a quick Calc shows 20 bottles needed for a 50% mix in a 5 gal container.

i think I'm gonna have to start in a 1 gal container!

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46 minutes ago, oneway said:

Wow,

a quick Calc shows 20 bottles needed for a 50% mix in a 5 gal container.

i think I'm gonna have to start in a 1 gal container!

I don't recall anyone advocating a 50/50 mix. If I recall,  one can of Seafoam Motor Treatment treats up to 16 gallons of gas or diesel fuel. I would use half can in 5 gal or if it is really gummed up a whole can in 5 gal.

Bill

 

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I had the same problem a few years ago. The Onan tech at a rally looked at it and replaced the brush assembly and everything started working fine.

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Straight from the Seafoam website:

For routine fuel system (gas tank to engine) maintenance, one can of Sea Foam Motor Treatment treats up to 16 gallons of gas or diesel fuel. When greater cleaning is needed, add more Sea Foam – the more you add to fuel, the better it cleans! When stabilizing fuel for storage, use 1 (one) ounce per gallon of fuel.Jan 1, 2016

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Mid day update:

I have another certified Onan tech (for a 2nd opinion) here at the coach who has never seen this before.

I am showing 118V at both breakers with the gen set running. The voltage drops when trying to start the 2nd A/C.

With one A/C running no problem, even when adding in the microwave.

Both A/C's run fine on shore power.

hmmm.

 

I told him to go ahead and change the fuel filters, air filter (oily), and replace spark plugs as a start since he's here.

I am in Yuma so I could head to the FMCA rally in PHX for a day or 2 and try to talk to an Onan Guy in person if there was a chance they'd be onsite.

I'll do the sea foam at some point as well. I'm thinking the easiest way is to just introduce into the fuel tank at appropriate mixture and let everything run.

Could the 2nd A/C have a compressor issue that only showed up on the genset ? Just thinking out loud......

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2nd update:

No change in operation after 2nd tech visit.

He thinks I have a carburetor issue. He doesn't think I have anything internally wrong with the gen set like the 1st tech did. The spark plugs weren't oily. He says a broken ring like the 1st tech thought would have shown up in oily spark plugs.

He specifically recommended against the sea foam because in his words it would take any varnish in the carb bowl and deposit it in the passageways.He urged me not to use it.

Now on to a new discovery:

The rear A/C bogs down the gen set by itself. I didn't realize that before. The front A/C operates normally using genset and both from and rear A/C's operate normally on shore power.

Which brings me back to wondering if it's possible that an A/C compressor would hang up on the genset thats verified at 118V output but have no problem on shore power.

Could it be the rear A/C compressor by itself? Or maybe a "compound fracture" with a combo of the rear A/C compressor and gen set carb?

????

 

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Try putting an amprobe clamp on meter on the circuit to the second ac the amprobe will capture startup current and running current the campground electrician should have one mayby he'll help you out only takes 5 minuets to do not counting drinking beers with him and thanking him for being a good sport. The Onan Tec.should have thought of it and done it an amprobe is a tool he should have for that kind of troubleshooting. You can check both AC units and see if #2 is actually the culprit. I am an electrician and do work at a cg on cape cod I would gladly help another camper out. Buy the way shore power usually has enough reserve capacity to power it on however you may notice it strugle to start. Might only be a start cap easy repair.

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6 minutes ago, oneway said:

2nd update:

no change in operation after 2nd tech visit.

he thinks I have a carburetor issue. He doesn't think I have anything internally wrong with the gen set like the 1st tech did. The spark plugs weren't oily. He says a broken ring like the 1st tech thought would have shown up in oily spark plugs.

He specifically recommended against the sea foam because in his words it would take any varnish in the carb bowl and deposit it in the passageways.He urged me not to use it.

now on to a new discovery:

the rear A/C bogs down the gen set by itself. I didn't realize that before. The front A/C operates normally using genset and both from and rear A/C's operate normally on shore power.

which brings me back to wondering if it's possible that an A/C compressor would hang up on the genset thats verified at 118V output but have no problem on shore power.

could it be the rear A/C compressor by itself? Or maybe a "compound fracture" with a combo of the rear A/C compressor and gen set carb?

????

 

I am still of the opinion it maybe a bad or failing start capacitor. It could be a failing compressor but I would change the start capacitor first.

The part about not showing up on shore power is, unless you are watching a meter to see if the load increases you might not be able to tell. You don't have the auditory clues that the load has gone up.

Just because he has "teck" on his hat mean he was at the top of his class.:o I would still (using the gas can method) run a mixture through the generator as I described before. Just use a piece of fuel line and hook up to the generator before the fuel pump.

Bill

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FIVE.  16 ounces. $8.95, treats 16 gal. of gas or diesel fuel.  You and me, about 9 cans each, $81 + Tax.  There are other products out there, like Lucas.

Carl

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2 minutes ago, Corona4me said:

IF...The Gen is running fine except the fact of the LOAD why would the fuel be suspect??

The higher the load, the more fuel demanded. So collapsed fuel line, etc should show up more.

And, if a leak on the suction side allowing air in, the more fuel demanded, the more "vacuum" to pull in air.

And, while not absolutely a "fuel issue", if the carburetor is gummed up, it may not give the proper mixture at high throttle settings-- depends on what is gummed up.

Same basic issues can happen with the main engine.

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54 minutes ago, WILDEBILL308 said:

I am still of the opinion it maybe a bad or failing start capacitor. It could be a failing compressor but I would change the start capacitor first.

The part about not showing up on shore power is, unless you are watching a meter to see if the load increases you might not be able to tell. You don't have the auditory clues that the load has gone up.

Just because he has "teck" on his hat mean he was at the top of his class.:o I would still (using the gas can method) run a mixture through the generator as I described before. Just use a piece of fuel line and hook up to the generator before the fuel pump.

Bill

You may be on to something here. 

Latest update:

I plugged in a line voltage monitor and was able to see what I could not hear. The line monitor shows a drop while trying to start the rear A/C, then comes back up (I'm assuming because it only does a momentary attempt?) So I suspect the rear A/C is not starting on shore power as well even though the fan runs.

So... as you can tell I'm not a tech, but it seems like a start cap on the rear A/C is in order as a starting point.

Now it's off to view a few videos to see how hard that is to pull off. Any input?

Am I on the right track after 2 "tech" visits?

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Certainly a start capacitor is a relatively inexpensive and easy to replace part that could/would cause high amp start up loads.

Be sure you discharge the capacitor before working on it!

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After all the Tech's...I do believe, There aren't any in Yuma...So, for Generator find a Cummins dealership...preferable a Cummins Coach Care Center, Google it to find one near you.  Cummins own Onan!

Carl

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The start cap is easy to replace, many AC units also have a PTC or timer relay.  In the case of the PTC they usually burn up and need to be replaced.  They usually come as a kit and some manufactures call them a hard start kit.  They usually burn up when the line voltage dips down to about 104 volts.  The condenser fan will run but the compressor will no start ,just hums and draws high Amps till the therminal protection cuts out.  Some times you can smell a burning smell when they fail.  When you remove the cover for the electrical connections where the capacitor is you may find 3 capacitors, 1 start, 1 run and one for the condenser fan.  Sometimes the start and run capacitor is one unit and will have 3 terminals on it instead of 2.  The burnt PTC and capacitor is usually easy to spot.  I would buy a second kit if you have 2 AC units, mine failed with in a year of each other and I now carry a spair.  They can be purchased for some units from camping world or RV parts supply as well as from  electrical motor repair places.  The last option is usually the cheapest.

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