CLASS RACER FORUM - View Single Post

Rich Biebel · 08-05-2014, 09:59 PM

Sean, this is exactly what happens when I have tested some. I purposely let them run and get hot....I shut them down and let the machine heat soak....The trouble usually starts right after doing this. I swap in a different PC board once the machine starts shutting down.

I have also sometimes just pressed on the face of the potting material of the board and got it to stop shutting down.

You did way more than most people would do and did it all to perfection.

I do the same things and come up with no clear bad readings....

You need to monitor that voltage at the carb solenoid if you really want to say 100% for certain that is what is happening. PC board voltage supply out to carb fuel solenoid fails when hot.

You could.....do what some creative racers have done....and power that solenoid separately with a switch....I think it is also the fuel pump supply circuit and believe it also may need to be fed separately.

Diesel Onans have done the same thing.....fuel pump circuit fails....they added a separate switch fed 12 volts to their fuel pump...

In your case it is the carbs fuel solenoid that is not getting power. It is just a small pin that retracts and allows fuel to be drawn up into the main jet....

Or you could defeat the pin entirely.....cut it or grind it off so it can't shut off the fuel......Think of how many carbs never had a device like that on small engines....What's the worst that could happen....Not much. Ignition magnetos get grounded for shutdown....engine might "run on" or diesel a little but I doubt it......You would still need to power the fuel pump separately so it stayed running anytime you wanted the generator to run.

Just throwing that out there for you. I never tried it as I have to fix these things by the book for customers.....

I have had racers tell me they added separate fuel pump voltage supply switches on diesels that do the same thing....random shutdowns....It is the PC board on those as well....they bypass the PC board and feed the fuel pump independently.....off a switch......

I am not recommending this type of repair but only mentioning it to show what some creative and resourcefull people have done to fix their generators....

08-05-2014, 09:59 PM	#20
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,314 Likes: 25 Liked 544 Times in 213 Posts	Re: Onan 7000 Generator problems Sean, this is exactly what happens when I have tested some. I purposely let them run and get hot....I shut them down and let the machine heat soak....The trouble usually starts right after doing this. I swap in a different PC board once the machine starts shutting down. I have also sometimes just pressed on the face of the potting material of the board and got it to stop shutting down. You did way more than most people would do and did it all to perfection. I do the same things and come up with no clear bad readings.... You need to monitor that voltage at the carb solenoid if you really want to say 100% for certain that is what is happening. PC board voltage supply out to carb fuel solenoid fails when hot. You could.....do what some creative racers have done....and power that solenoid separately with a switch....I think it is also the fuel pump supply circuit and believe it also may need to be fed separately. Diesel Onans have done the same thing.....fuel pump circuit fails....they added a separate switch fed 12 volts to their fuel pump... In your case it is the carbs fuel solenoid that is not getting power. It is just a small pin that retracts and allows fuel to be drawn up into the main jet.... Or you could defeat the pin entirely.....cut it or grind it off so it can't shut off the fuel......Think of how many carbs never had a device like that on small engines....What's the worst that could happen....Not much. Ignition magnetos get grounded for shutdown....engine might "run on" or diesel a little but I doubt it......You would still need to power the fuel pump separately so it stayed running anytime you wanted the generator to run. Just throwing that out there for you. I never tried it as I have to fix these things by the book for customers..... I have had racers tell me they added separate fuel pump voltage supply switches on diesels that do the same thing....random shutdowns....It is the PC board on those as well....they bypass the PC board and feed the fuel pump independently.....off a switch...... I am not recommending this type of repair but only mentioning it to show what some creative and resourcefull people have done to fix their generators.... __________________ Rich Biebel S/C 1479 Stock 147R Last edited by Rich Biebel; 08-05-2014 at 10:09 PM.