The Onan P series "Governor issue"

[RED-Z06 2,567]

Its always made me kinda shy away from them but i always seem to end up with Onans...it was a short sighted cost saving design to go from the steel ball spacer to plastic, i wonder how many good engines have died from over speeding due to a slipping plate.  The worst part is its gradual and heat sensitive.  You may not realize its happening as the speed creeps up.

 

Im shortly going to be doing a steel spacer retrofit on a P220G that had a pretty pronounced runaway after about 10 minutes of running.  Cold it held 3600rpms no problem, after 10 minutes it was still holding 3630, but reduce speed to idle and rev it...it hit 4400 for about a second before settling into 4000rpms...classic symptoms.

[kpinnc 14,630]

59 minutes ago, RED-Z06 said:

Cold it held 3600rpms no problem, after 10 minutes it was still holding 3630, but reduce speed to idle and rev it...it hit 4400 for about a second before settling into 4000rpms...classic symptoms.

 

Mine always acts like that. I've not let it go to 4K, but it's definitely Speedy on throttle up when warm.

 

I had no idea. I thought it was normal, or at least nothing more than a sticky throttle lever... Learned sumptin y'all! 

Edited February 4, 2022 by kpinnc

[RED-Z06 2,567]

18 minutes ago, kpinnc said:

 

Mine always acts like that. I've not let it go to 4K, but it's definitely Speedy on throttle up when warm.

 

I had no idea. I thought it was normal, or at least nothing more than a sticky throttle lever... Learned sumptin y'all! 

Yeah, the governor is a cup shaped cam gear, 5 balls and a plastic spacer that holds the balls..then a cup that rides on the balls and pushes them to the center.  The cam speeds up, the balls speed up, they push out and force the cup out..which acts on the governor rod.  When the plastic slips..the balls delay their reaction.  Eventit breaks and you very suddenly lose all governor control..pins it wide open

[RED-Z06 2,567]

[Handy Don 14,057]

2 hours ago, RED-Z06 said:

Yeah, the governor is a cup shaped cam gear, 5 balls and a plastic spacer that holds the balls..then a cup that rides on the balls and pushes them to the center.  The cam speeds up, the balls speed up, they push out and force the cup out..which acts on the governor rod.  When the plastic slips..the balls delay their reaction.  Eventit breaks and you very suddenly lose all governor control..pins it wide open

To get a spare spacer is one reason I bought a parts p220 with other problems. Still and all, I'm hoping I'll never have to go into two engines to retrieve the part from one and put it into the other.

[RED-Z06 2,567]

Just now, Handy Don said:

To get a spare spacer is one reason I bought a parts p220 with other problems. Still and all, I'm hoping I'll never have to go into two engines to retrieve the part from one and put it into the other.

Therein lies an issue though..the plastic itself, it gets so Brittle it would probably shatter on removal.  Isavetracytors has a steel option...im hoping it works

[lynnmor 7,813]

5 hours ago, RED-Z06 said:

Therein lies an issue though..the plastic itself, it gets so Brittle it would probably shatter on removal.  Isavetracytors has a steel option...im hoping it works

 

Now that is a good deal.  The ad says metal, but not what kind.  There is someone on Fakebook selling aluminum ones for more than twice that much. 

[RED-Z06 2,567]

24 minutes ago, lynnmor said:

 

Now that is a good deal.  The ad says metal, but not what kind.  There is someone on Fakebook selling aluminum ones for more than twice that much. 

Not sure of the metallurgical content but its definitely ferrous.

[lynnmor 7,813]

1 minute ago, RED-Z06 said:

Not sure of the metallurgical content but its definitely ferrous.

 

So you have one already?

I made a tool to guide the spacer on evenly, It uses a pin in the center for alignment and the body of it is hammered home.

[RED-Z06 2,567]

He says to pull the cam gear and press it on...that it will crack otherwise.

 

Im not going to do that, my plan is to measure both and see the tolerance, then heat the spacer, cool the gear, and see if it becomes a thermal slip fit...if so ill put some retaining compound on the gear and drop the spacer on.

[RED-Z06 2,567]

3 minutes ago, lynnmor said:

 

So you have one already?

I made a tool to guide the spacer on evenly, It uses a pin in the center for alignment and the body of it is hammered home.

Oh yes, in hand 

[lynnmor 7,813]

30 minutes ago, RED-Z06 said:

He says to pull the cam gear and press it on...that it will crack otherwise.

 

Im not going to do that, my plan is to measure both and see the tolerance, then heat the spacer, cool the gear, and see if it becomes a thermal slip fit...if so ill put some retaining compound on the gear and drop the spacer on.

 

That is one reason that I wondered about material.  The coefficient of expansion may be different between the spacer and the hub where it is mounted.  You can do the math, but my thought is that a slip fit from the temperature difference may not be enough.  Keep in mind that the temperature difference will quickly be lost as the parts come into contact, so work real fast, a driver like I explained will allow you to get it home quickly.   When he said that it will crack, did he mean the spacer from beating on the segments?  I used Super Glue on plastic ones and they are still holding. 

[RED-Z06 2,567]

31 minutes ago, lynnmor said:

 

That is one reason that I wondered about material.  The coefficient of expansion may be different between the spacer and the hub where it is mounted.  You can do the math, but my thought is that a slip fit from the temperature difference may not be enough.  Keep in mind that the temperature difference will quickly be lost as the parts come into contact, so work real fast, a driver like I explained will allow you to get it home quickly.   When he said that it will crack, did he mean the spacer from beating on the segments?  I used Super Glue on plastic ones and they are still holding. 

He only said if you hammer it on it will crack.

[bc.gold 3,406]

I'm still considering the make those ball spacers, one of  the circuit boards inside my induction furnace cracked. I managed to get a replacement from the vendor in China but took four months to arrive. Just in time for winter.