Onan P220 surging/hunting at operate

[Handy Don 10,567]

Me, I love being thorough. I've learned, though, that sometimes it's best to leave well enough alone! 

 

 

Edited July 30, 2021 by Handy Don

[WheelHorse520H 706]

Just now, Handy Don said:

Me, I love being thorough. I've learned, though, that sometimes it's best to leave well enough alone! 

 

 

Then I guess if it continues to surge I have an idea of where to look. Thanks for the advice.

[Handy Don 10,567]

1 minute ago, WheelHorse520H said:

Then I guess if it continues to surge I have an idea of where to look. Thanks for the advice.

That connection is under little or no mechanical stress, really. Your only real risk is if someone opened it and then didn't use a new gasket to close it up and the bad seating would allow air to enter through the joint when there is a lot of vacuum in the intake. Given what you've already gone through, it'd ease your mind to replace that gasket so do it. 

[WheelHorse520H 706]

2 minutes ago, Handy Don said:

That connection is under little or no mechanical stress, really. Your only real risk is if someone opened it and then didn't use a new gasket to close it up and the bad seating would allow air to enter through the joint when there is a lot of vacuum in the intake. Given what you've already gone through, it'd ease your mind to replace that gasket so do it. 

Okey dokey.

[WheelHorse520H 706]

Valve covers painted and installed, cylinder heads installed, spark plugs installed and carb to spacer gasket installed. Check, check, check, and check. Next I mount the intake and carb together correct? I cannot find the gasket that goes between the spacer and manifold. If anyone knows the part number that would be a huge help.

Edited July 30, 2021 by WheelHorse520H

[Handy Don 10,567]

4 hours ago, WheelHorse520H said:

Valve covers painted and installed, cylinder heads installed, spark plugs installed and carb to spacer gasket installed.

Looking mighty fine, there. Didn't realize you were doing all this with the engine mounted. I removed mine to a bench to do all the work (and used a small winch to hoist it off and on) for access and to work at a good height.

[lynnmor 6,762]

9 hours ago, WheelHorse520H said:

Done. There are a few little spots left but I think it’s good. Paint on the valve covers is drying, installing those in 1 hour. I will try to separate the spacer on the carb so you can see what @Handy Don was talking about.

 

Did you countersink the tapped holes and run a tap in them?  Did you clean up the block surface?   Looks like you are well under way.

Edited July 31, 2021 by lynnmor

[WheelHorse520H 706]

6 minutes ago, lynnmor said:

 

Did you countersink the tapped holes and run a tap in them?

Crap!!!! No… I got too excited putting it all together.

 

9 minutes ago, lynnmor said:

Did you clean up the block surface?

Was that what the steel wool was for? I used it on the heads.

 

9 minutes ago, lynnmor said:

Looks like you are well under way.

I am… well was. I need to take it apart and do all that don’t I? That’s okay, the longest part is threading the rear head bolts because of the space restriction.

[lynnmor 6,762]

Just now, WheelHorse520H said:

Crap!!!! No… I got too excited putting it all together.

 

Was that what the steel wool was for? I used it on the heads.

 

I am… well was. I need to take it apart and do all that don’t I? That’s okay, the longest part is threading the rear head bolts because of the space restriction.

I wouldn't tear it apart, it is probably fine.  Yes, the block surface is just as important as the head surface.  The idea is to remove the "probably" from the assembly.  It is best to not reuse gaskets and it will be better for them to leave it alone and proceed.

[WheelHorse520H 706]

3 minutes ago, lynnmor said:

I wouldn't tear it apart, it is probably fine.  Yes, the block surface is just as important as the head surface.  The idea is to remove the "probably" from the assembly.  It is best to not reuse gaskets and it will be better for them to leave it alone and proceed.

Okay, thanks. I will be sure to do that from now on. Do you know if the gasket for between the carb spacer and intake manifold was also used on the oil dipstick tube or was that between the spacer and the carb itself?

[lynnmor 6,762]

21 minutes ago, WheelHorse520H said:

Okay, thanks. I will be sure to do that from now on. Do you know if the gasket for between the carb spacer and intake manifold was also used on the oil dipstick tube or was that between the spacer and the carb itself?

 

You have a very early model of the 520 Wheelhorses and I am not sure of what you are asking about the dipstick tube.  Later models had the clamp for the dipstick tube held by one of the bolts that mounts the intake manifold.  Later models do not use the carburetor spacer. 

 

Since the title of this thread is:

"Onan P220 surging/hunting at operate,"

I wonder why I am seeing a dirty carburetor that probably hasn't been thoroughly cleaned inside.  Dirty carburetors is the cause of the vast majority of the surging problems.

[WheelHorse520H 706]

5 minutes ago, lynnmor said:

 

You have a very early model of the 520 Wheelhorses and I am not sure of what you are asking about the dipstick tube.  Later models had the clamp for the dipstick tube held by one of the bolts that mounts the intake manifold.  Later models do not use the carburetor spacer. 

I was trying to find the gasket that goes between the spacer and the manifold and onanparts.com had two gaskets (the 5th and 6th ones down) that appear to be the same but I believe one is larger than the other. The 5th one down (a tan-like color) says it was also used where the oil fill tube connects to the oil base. The one below it does not say that though making me think it is a different size.

 

13 minutes ago, lynnmor said:

Since the title of this thread is:

"Onan P220 surging/hunting at operate,"

I wonder why I am seeing a dirty carburetor that probably hasn't been thoroughly cleaned inside.  Dirty carburetors is the cause of the vast majority of the surging problems.

I did (believe it or not) clean the inside twice. Once before I joined RS I saw another thread with the same symptoms and instructions to clean as you gave, and then again after I created this thread following the manual (I believe the directions I followed the first time were taken from the manual because they had me do the same thing, except with the engine still together) and took a little carb cleaner too the outside after I put it back together. It did look better, no shine for sure but (again believe it or not) it was cleaned. I might clean it again since I have to wait for the starter cone we talked about and to find a gasket and have it shipped. I believe this critique was hinting at something… maybe another good carb cleaning. So that’s what it’ll get, everything you have told me before has cleaned this engine up so I’ll do it again. I really appreciate all your help,

Andrew

[lynnmor 6,762]

You might need this carburetor gasket.  The oil fill gasket makes no sense to me.

 

Did you pop off the plastic limiter cap on the idle mixture screw and then remove the screw followed by a blast of cleaner in there?

 

Did you remove any welch plug and blast cleaner in there?

 

What make and model carburetor do you have, can you provide better photos of it?

[WheelHorse520H 706]

9 hours ago, lynnmor said:

You might need this carburetor gasket.

That looks like the right one, thank you. I just checked and the 6th one down on the page I linked is the one I bought from Colburn and the 5th one down is for carbs that mount on the side not the top. Making me believe (even more) the one you linked is the correct one. Should I order it tomorrow?

 

9 hours ago, lynnmor said:

The oil fill gasket makes no sense to me.

Honestly me neither that’s why I was asking about it, I hoped someone on here would know.

 

9 hours ago, lynnmor said:

Did you pop off the plastic limiter cap on the idle mixture screw and then remove the screw followed by a blast of cleaner in there?

Yes.

 

9 hours ago, lynnmor said:

 

Did you remove any welch plug and blast cleaner in there?

 No, mostly because I don’t know where the Welch plug is or what it looks like.

 

9 hours ago, lynnmor said:

What make and model carburetor do you have, can you provide better photos of it?

Here you go…

Thanks,

Andrew

Edited July 31, 2021 by WheelHorse520H

[Tuneup 1,416]

Coffee sip...

The plug is directly above the idle screw. Mine was missing...

[WheelHorse520H 706]

The one in the first photo is the idle stop screw. The one in the seconds photo (on the side with the plastic cap) is the idle screw. Correct?

[lynnmor 6,762]

55 minutes ago, WheelHorse520H said:

The one in the first photo is the idle stop screw. The one in the seconds photo (on the side with the plastic cap) is the idle screw. Correct?

 

 

The plastic cap your yellow arrow is pointing to is the idle mixture screw.  Take a photo from that side so we can see if there is a welch plug just above it.

[WheelHorse520H 706]

Is it the little shiny metal cap that the arrow on the idle screw is pointing to?

[lynnmor 6,762]

57 minutes ago, WheelHorse520H said:

Is it the little shiny metal cap that the arrow on the idle screw is pointing to?

 

Yep, they are removed by drilling a small hole in the center and pried out with a pick.  You can also start a screw in the hole, then grab that screw and pull it out.  If you drill more than just thru the plug or run the screw in too far, you will need to replace the carburetor.  There are 3 small holes in there that need to be cleaned.  Before starting the job, find a 3/8" aluminum welch plug for replacement.  When inserting the new plug, put a VERY small amount of sealant on the edge, then push it in and tap on the dome till it dimples in just a bit and that will hold it in place.

[Handy Don 10,567]

Just being annoyingly clear....the welch plug is that metallic dome where the red arrow is pointing.

You'll likely have to pop off the idle adjuster cap to get clear access. 

 

Frankly, given all the work you've done elsewhere, take the time and effort to thoroughly clean the outside of the carb before pulling that plug or doing any other work on the carb. A retired soft toothbrush and carb cleaner work well to get all the nooks and crannies.  Handling a dirty carb is an invitation to introducing dirt where it'll mess with the operation.

 

[WheelHorse520H 706]

7 hours ago, lynnmor said:

 

Yep, they are removed by drilling a small hole in the center and pried out with a pick.  You can also start a screw in the hole, then grab that screw and pull it out.  If you drill more than just thru the plug or run the screw in too far, you will need to replace the carburetor.  There are 3 small holes in there that need to be cleaned.  Before starting the job, find a 3/8" aluminum welch plug for replacement.  When inserting the new plug, put a VERY small amount of sealant on the edge, then push it in and tap on the dome till it dimples in just a bit and that will hold it in place.

Does the plug have to be brand specific? What do you mean by sealant? Is it like gas-safe RTV? 

5 hours ago, Handy Don said:

 

Just being annoyingly clear....the welch plug is that metallic dome where the red arrow is pointing.

 

Be annoyingly clear, that is how we avoid an accident with a miscommunication.

 

5 hours ago, Handy Don said:

Frankly, given all the work you've done elsewhere, take the time and effort to thoroughly clean the outside of the carb before pulling that plug or doing any other work on the carb. A retired soft toothbrush and carb cleaner work well to get all the nooks and crannies.  Handling a dirty carb is an invitation to introducing dirt where it'll mess with the operation.

I know I need more carb cleaner, will pick that up this week.

Thanks,

Andrew

[lynnmor 6,762]

I use this for sealing carburetor and intake manifolds.

 

I understand that this welch plug works, I have never ordered that one.  I did check a new rebuild kit and the plug in it measures .378" for a 3/8" hole.

[WheelHorse520H 706]

1 hour ago, lynnmor said:

I use this for sealing carburetor and intake manifolds.

This is for the Welch plug right?

 

1 hour ago, lynnmor said:

 

I understand that this welch plug works, I have never ordered that one.  I did check a new rebuild kit and the plug in it measures .378" for a 3/8" hole.

Ok, I will order that and the new gasket this week.

Thanks,

Andrew

[WheelHorse520H 706]

Okay, I have two welch plugs on the way (in case I mess up or need another later on) and I tried to order the gasket I need from Colburn Power but they have a rule that you need to order at least $25 and the gasket is only $3, so I am going to see if the local small engine shop has any. I countersunk the bolt holes and vacuumed the shavings, I will clean the threads later today. Also, the spring for the PTO fell off since the bracket is disconnected, does anyone know where it hooks? Thanks,

Andrew

Edited August 3, 2021 by WheelHorse520H

[lynnmor 6,762]

22 hours ago, WheelHorse520H said:

Okay, I have two welch plugs on the way (in case I mess up or need another later on) and I tried to order the gasket I need from Colburn Power but they have a rule that you need to order at least $25 and the gasket is only $3, so I am going to see if the local small engine shop has any. I countersunk the bolt holes and vacuumed the shavings, I will clean the threads later today. Also, the spring for the PTO fell off since the bracket is disconnected, does anyone know where it hooks? Thanks,

Andrew

 

Buy some gasket material at an auto parts store and make one.

 

This thread should help with your PTO spring problem, but first make that opened loop look like the opposite end.