After struggling with my 4BGE Spec G generator off and on for a year, I also considered putting one of those cheap import generators in place of my Onan.
Then I watched the 24 hour torture test between an ancient Onan that looked like it had been pulled out of a swamp and a brand new Champion. Champion went about 25 hours before the engine destroyed itself.
If you are not experienced with generators, it can seem like a mysterious "black box". They really aren't so complicated.
The Onan motors are pretty bullet proof. As long as you don't run them out of oil, the mechanical portion of your generator will probably never give you any problems.
Thus the problems are either going to be electrical or carburetor related.
Onan service manuals provide detailed information on how to rebuild carburetors. They can be tricky to work on as there are some tiny, fragile parts. Or, you can just replace the carb for about $300 if you do it yourself, depending on your genny.
The starter is easy to replace and cheap if you go aftermarket.
The coil is easy to replace and cheap if you go aftermarket.
The ignition control module can be pricey but is easy to replace.
The control board is pricey but easy to replace.
The voltage regulator is pricey but easy to replace.
On my Onan 4BGE, you can replace the entire ignition electrical system and the starter for about $200 if you do the work yourself. Much less hassle than trouble shooting.
The key to these things, as has already been noted, is you have to run them. You need to run them monthly under load for two major reasons: First, you need to keep fresh gas running through the carb, with vibrations and heat working to get rid of gum buildup in the carb. Second, it keeps the slip rings clean. If they get get dirty, then the resistance between the brushes increases. This can damage the voltage regulator, which is a $200+ component on my genny.
If you're not willing to tackle your generator, you can pretty much count on spending at least $500 the minute you drive it into a shop.
Steve
Then I watched the 24 hour torture test between an ancient Onan that looked like it had been pulled out of a swamp and a brand new Champion. Champion went about 25 hours before the engine destroyed itself.
If you are not experienced with generators, it can seem like a mysterious "black box". They really aren't so complicated.
The Onan motors are pretty bullet proof. As long as you don't run them out of oil, the mechanical portion of your generator will probably never give you any problems.
Thus the problems are either going to be electrical or carburetor related.
Onan service manuals provide detailed information on how to rebuild carburetors. They can be tricky to work on as there are some tiny, fragile parts. Or, you can just replace the carb for about $300 if you do it yourself, depending on your genny.
The starter is easy to replace and cheap if you go aftermarket.
The coil is easy to replace and cheap if you go aftermarket.
The ignition control module can be pricey but is easy to replace.
The control board is pricey but easy to replace.
The voltage regulator is pricey but easy to replace.
On my Onan 4BGE, you can replace the entire ignition electrical system and the starter for about $200 if you do the work yourself. Much less hassle than trouble shooting.
The key to these things, as has already been noted, is you have to run them. You need to run them monthly under load for two major reasons: First, you need to keep fresh gas running through the carb, with vibrations and heat working to get rid of gum buildup in the carb. Second, it keeps the slip rings clean. If they get get dirty, then the resistance between the brushes increases. This can damage the voltage regulator, which is a $200+ component on my genny.
If you're not willing to tackle your generator, you can pretty much count on spending at least $500 the minute you drive it into a shop.
Steve
The place to go for Onan trouble shooting is here:
https://www.smokstak.com/forum/forumdisplay.php?f=1
They also have factory service manuals for your models, which include diagnostic procedures.
I'm in the middle of fighting with my Onan and have been for months. This week I'm pulling the voltage regulator and control board (both Flight Systems replacements replaced in 2009) and sending them in for testing ($35 each which they refund if you buy a new board).
Steve
https://www.smokstak.com/forum/forumdisplay.php?f=1
They also have factory service manuals for your models, which include diagnostic procedures.
I'm in the middle of fighting with my Onan and have been for months. This week I'm pulling the voltage regulator and control board (both Flight Systems replacements replaced in 2009) and sending them in for testing ($35 each which they refund if you buy a new board).
Steve
harold1946 wrote:My slick stick was $19.95 plus $10.00 S/H.
The tool for cleaning is called a slick- stick and are available online for around $25.00. Not a difficult job, but on some the genny must be removed.
Arrived with detailed instructions. Very happy. At the time could not find it directly as an orderable item on the flightsystems.com website but was able to call and get it.
Be sure to check out the Youtube channel for detailed troubleshooting of Onan generators.
