Onan P220-G Exhaust/ Muffler Work

[Horse Newbie 7,114]

I noticed a crack in my exhaust pipe/ muffler where the rear pipe ties into the muffler.

I am going to take it off, have it sand/ bead blasted, welded, and paint it with Rustoleum High Temp. paint.

My question is...Any particular care need to be taken when I remove the exhaust pipe flange bolts ? ( Right now I have the bolts soaking overnight with PB Blaster.)

When I rebolt everything back up I plan on using Onan Exhaust gaskets. Do I need to use Threadlocker on the bolts when I rebolt ? And what strength of Threadlocker and what torque ?

 

Tim, aka Horse Newbie

 

[Achto 27,751]

12 minutes ago, Horse Newbie said:

Do I need to use Threadlocker on the bolts when I rebolt ?

 

Quite personally I would use anti-seize on such an application. Rely on lock washers to keep the bolts from backing out.

[Horse Newbie 7,114]

14 minutes ago, Achto said:

 

Quite personally I would use anti-seize on such an application. Rely on lock washers to keep the bolts from backing out.

Good idea...thanks !

Now that I think of it you hit the nail on the head...I used to use Anti-Seize on commercial oven door parts...stands up to heat and still prevents seizing.

[Horse Newbie 7,114]

Well I got my muffler and heat shield primed with Rustoleum 2000 degree primer...no hurry...Im waiting on other parts to arrive

[Horse Newbie 7,114]

Notice the concave bottom galvanized fire bucket hanging on the garage door track ?

[Horse Newbie 7,114]

On 9/27/2020 at 10:14 PM, Achto said:

 

Quite personally I would use anti-seize on such an application. Rely on lock washers to keep the bolts from backing out.

@Achto , @WVHillbilly520H I noticed in my service manual for the P220 it says torque the exhaust manifold to 9-11 ft/lbs.

Would you do that, let it get to temp and re-torque, or no...

[Achto 27,751]

Tighten them to specs & run it. Maybe check them periodically to make sure they are staying tight.

[WVHillbilly520H 10,374]

50 minutes ago, Horse Newbie said:

@Achto , @WVHillbilly520H I noticed in my service manual for the P220 it says torque the exhaust manifold to 9-11 ft/lbs.

Would you do that, let it get to temp and re-torque, or no...

I had mine apart twice... "Torqued" by "feel" and never bothered again. 

[Horse Newbie 7,114]

@WVHillbilly520H and @Achto and @lynnmor .... a little help here please.

As you can see by the video I got enough stuff buttoned up on my 94' 520H to get it running...

Happy Day... been about 3 years since I brought it home, cleaned a little and rolled her inside.

I know from Red square that you are going to tell me dirty carb because it is searching.

Would you rebuild , run Seafoam through her and see what happens, carb off ebay, or what ?

Also...on the Seafoam, would it hurt to dump a whole can in the fuel tank(full) or go by recommendations on can ?

See video at end of pics please.

 

Thanks, Tim

[lynnmor 7,353]

While the exhaust was off would have been an excellent time to pull the intake and carburetor.  With the valve covers buried under the manifolds it would have been a good idea to have adjusted the valves as well.  I am no fan of snake oil, if there is debris in the carburetor then physically remove it.  For now you can pull the carburetor top to see what is in there and clean as best you can.

[WVHillbilly520H 10,374]

If you were to "choke" while idling does the "searching" smooth out? If so like Lynmoor said pull the top and clean as much as you can using spray carb/jet cleaner in every orifice (make sure to shield your eyes) reassemble try again ... May need to do this several times... Not a fan of Seafoam as much i like Berrymans B12 for fuel system cleaning i personally use about 1/4 or can per tank... And actual small engine shop back home swore by Marvel Mystery Oil in the crankcase and fuel tank for Kohlers and my dad used it religiously without much issue.

[Horse Newbie 7,114]

27 minutes ago, lynnmor said:

While the exhaust was off would have been an excellent time to pull the intake and carburetor.  With the valve covers buried under the manifolds it would have been a good idea to have adjusted the valves as well.  I am no fan of snake oil, if there is debris in the carburetor then physically remove it.  For now you can pull the carburetor top to see what is in there and clean as best you can.

Yeah I was wondering if I should have adjusted the valves...but not being what I would call a mechanic I was afraid I would do something wrong and tear something up. @lynnmor take a look at the video attached and tell me what you think.

I could lower the throttle to almost or/at idle and put my finger over the little hole in the carb then it seemed to smooth out some.

By the way, I got my hour gauge working by following your directions...

The oil pressure switch with the 3 terminals worked...

Ran blue wire to indicator light...

Black wire to "-" on hour meter...

And figured out which terminal to ground to block.

Thanks for the help !

If I get the carb issue straightened out, and she runs good I may have to study on adjusting the valves.

I know I've gotten off topic.

Tim (Horse Newbie)

[Horse Newbie 7,114]

20 minutes ago, WVHillbilly520H said:

If you were to "choke" while idling does the "searching" smooth out? If so like Lynmoor said pull the top and clean as much as you can using spray carb/jet cleaner in every orifice (make sure to shield your eyes) reassemble try again ... May need to do this several times... Not a fan of Seafoam as much i like Berrymans B12 for fuel system cleaning i personally use about 1/4 or can per tank... And actual small engine shop back home swore by Marvel Mystery Oil in the crankcase and fuel tank for Kohlers and my dad used it religiously without much issue.

Yes it seems to smooth out when I choke it a bit at idle...guess I'll be pulling the top off the carb at least...

[WVHillbilly520H 10,374]

Valve adjustment... 

 

[Horse Newbie 7,114]

@WVHillbilly520H , @lynnmor , @Achto Okay 520H / Onan P220 veterans...

Time to send the city boy to school...

Does the two do- hickeys need to come out that the blue pen is pointing to ?

Take a look at the pics...

the carb looked like a dumpster that had been sitting outside.(was outside when I bought it)

 

Do you think a soaking in Gunk carb cleaner will do it, or do I need to:

a.  Buy an ultrasonic parts cleaner.

b.  Buy carb on internet.

 

Also while this topic is all over the place, could one of you describe how to adjust the valves ?...

I ended up taking carb and manifold off/ aint no way taking just the top off carb off was gonna do it.

Look how corroded the bowl drain plug is.

Take a look at those valve stems in the pics and chime in please with your thoughts.

 

Thanks,

Tim ah...Horse Newbie

 

[Horse Newbie 7,114]

9 minutes ago, WVHillbilly520H said:

Valve adjustment... 

 

Ha !... You beat me to it Jeff...mind reader !...😝

[WVHillbilly520H 10,374]

You may be able to "soak" it out in a carb bucket (I prefer Berrymans over Gunk brand) you will definitely want to get a rebuild kit. That build up is from ethanol laced fuel, those parts you are pointing at with the ink pin are 1) the Welch plug it can come out but you will a new one then reseal when reunstalling 2) the idle limiter cap won't hurt to soak it, there are some new aftermarket carbs on eBay for $40... @lynnmor may be of more help or @cleat, I really haven't had too many issues with my Onans in the past 22 years. https://www.ebay.com/itm/164508116811. https://www.ebay.com/itm/353238601396

Edited November 13, 2020 by WVHillbilly520H

[Horse Newbie 7,114]

1 minute ago, WVHillbilly520H said:

You may be able to "soak" it out in a carb bucket (I prefer Berrymans over Gunk brand) you will definitely want to get a rebuild kit. That build up is from ethanol laced fuel, those parts you are pointing at with the ink pin are 1) the Welch plug it can come out but you will a new one then reseal when reunstalling 2) the idle limiter cap won't hurt to soak it, there are some new aftermarket carbs on eBay for $50... @lynnmor may be of more help or @cleat, I really haven't had too many issues with my Onans in the past 22 years. 

I'm leaning towards new carb for $50 or so...

Never rebuilt a carb.

I use non ethanol fuel in all my equipment( wish the previous owner did.

Okay @cleat and @lynnmor jump right in...what' s you fellows vote on the new carb or rebuild...

Remember never rebuilt a carb before.

 

[Horse Newbie 7,114]

1 hour ago, WVHillbilly520H said:

You may be able to "soak" it out in a carb bucket (I prefer Berrymans over Gunk brand) you will definitely want to get a rebuild kit. That build up is from ethanol laced fuel, those parts you are pointing at with the ink pin are 1) the Welch plug it can come out but you will a new one then reseal when reunstalling 2) the idle limiter cap won't hurt to soak it, there are some new aftermarket carbs on eBay for $40... @lynnmor may be of more help or @cleat, I really haven't had too many issues with my Onans in the past 22 years. https://www.ebay.com/itm/164508116811. https://www.ebay.com/itm/353238601396

@WVHillbilly520H  I ordered the carb in the link above.

I believe that will be the best route considering I could order a carb rebuild kit, rebuild carb, and it still not work and have to do it again.

I do believe that I will adjust the valves while I have it apart.

 

Thanks for the video !!

 

[lynnmor 7,353]

I'm not a fan of the cheap Chinese carburetors, some have good luck, others not so much.  "Rebuilding" a carburetor, that doesn't have excessive wear, simply means doing a meticulous cleaning.  Anyway, check that there are no leaks between the intake manifold halves and check if the heat shields cut into the side of it.  Cut a bit off the heat shields if they touch.  Use genuine Onan intake manifold gaskets, cheap Chinese gaskets will fail.

 

So you don't have to look for timing marks and still not have the cam in the best position, there is a simple way to get in the position to adjust a valve.  Choose a valve and rotate the engine to where the valve spring is compressed to the maximum amount, now mark the pulley with chalk and rotate the engine one full turn.  Adjust that valve and repeat till all four are done. Use the next size smaller and larger feeler gauges as go and no go gauges to be sure that you have it right.  If you find valves that are more than a few thousandths off specification, stop and report your findings.

 

Back to the dirty carburetor, The white plastic limiter cap can be pried off and the idle mixture screw will then come out.  That "drain plug" is just an access port to switch the main jet for different elevations.  The welch plug just above the idle mixture screw should be removed for cleaning, especially on a carburetor this dirty.  If you have success with the cheap  carburetor, I would be interested in the old one.

 

The white on the exhaust valve is the result of too little fuel getting thru the dirty carburetor, that isn't a problem unless the engine was run hard while running lean.  Many point to the valve seat issues in Onan engines, but any engine with removable valve seats can suffer damage from the abuse of running too lean.  Keep fresh fuel in your equipment and don't store it long term with ethanol fuel in the carburetor, run it dry for storage and any fuel can be used.  Even stored gas in cans should not be kept long term and keep the cans tightly closed except for quickly filling your equipment.  You can use the 10% ethanol fuel to save money, but follow the rules.  Be sure to thank your government leaders for the extra work.

 

With the exhaust painted, valves adjusted, carburetor cleaned, intake manifold inspected and all new gaskets you should be good for years to come.  As you are learning, shortcuts, (for example: snake oil) don't pay.

[Horse Newbie 7,114]

On 11/13/2020 at 3:57 AM, lynnmor said:

I'm not a fan of the cheap Chinese carburetors, some have good luck, others not so much.  "Rebuilding" a carburetor, that doesn't have excessive wear, simply means doing a meticulous cleaning.  Anyway, check that there are no leaks between the intake manifold halves and check if the heat shields cut into the side of it.  Cut a bit off the heat shields if they touch.  Use genuine Onan intake manifold gaskets, cheap Chinese gaskets will fail.

 

So you don't have to look for timing marks and still not have the cam in the best position, there is a simple way to get in the position to adjust a valve.  Choose a valve and rotate the engine to where the valve spring is compressed to the maximum amount, now mark the pulley with chalk and rotate the engine one full turn.  Adjust that valve and repeat till all four are done. Use the next size smaller and larger feeler gauges as go and no go gauges to be sure that you have it right.  If you find valves that are more than a few thousandths off specification, stop and report your findings.

 

Back to the dirty carburetor, The white plastic limiter cap can be pried off and the idle mixture screw will then come out.  That "drain plug" is just an access port to switch the main jet for different elevations.  The welch plug just above the idle mixture screw should be removed for cleaning, especially on a carburetor this dirty.  If you have success with the cheap  carburetor, I would be interested in the old one.

 

The white on the exhaust valve is the result of too little fuel getting thru the dirty carburetor, that isn't a problem unless the engine was run hard while running lean.  Many point to the valve seat issues in Onan engines, but any engine with removable valve seats can suffer damage from the abuse of running too lean.  Keep fresh fuel in your equipment and don't store it long term with ethanol fuel in the carburetor, run it dry for storage and any fuel can be used.  Even stored gas in cans should not be kept long term and keep the cans tightly closed except for quickly filling your equipment.  You can use the 10% ethanol fuel to save money, but follow the rules.  Be sure to thank your government leaders for the extra work.

 

With the exhaust painted, valves adjusted, carburetor cleaned, intake manifold inspected and all new gaskets you should be good for years to come.  As you are learning, shortcuts, (for example: snake oil) don't pay.

@lynnmor I closely inspected  the intake manifold and DID find where the heat shield was rubbing it.

Cleaned it up and resealed where the two halves meet. (see pics)

Also rotated my engine untill both vales were loose on the # 1 cylinder...

Am I ready to check/ adjust valves? (see video

)

Edited November 19, 2020 by Horse Newbie

[lynnmor 7,353]

Reread my instructions on adjusting the valves: "So you don't have to look for timing marks and still not have the cam in the best position, there is a simple way to get in the position to adjust a valve.  Choose a valve and rotate the engine to where the valve spring is compressed to the maximum amount, now mark the pulley with chalk and rotate the engine one full turn.  Adjust that valve and repeat till all four are done. Use the next size smaller and larger feeler gauges as go and no go gauges to be sure that you have it right.  If you find valves that are more than a few thousandths off specification, stop and report your findings."

 

Your last video will not play on my system.

 

If you didn't split the intake halves, the sealant on the outside will do nothing.  There are instructions at the top of the engines section describing one way to reseal an intake.  I don't tap the one half, I just use screws, washers and locknuts.  That groove in your photo is exactly what I was talking about, I believe that nearly all have that same issue.

[Horse Newbie 7,114]

@lynnmor  Thank you for all your help !

[Horse Newbie 7,114]

I'll try to repost the video. @lynnmor

[WVHillbilly520H 10,374]

3 hours ago, Horse Newbie said:

I'll try to repost the video. @lynnmor

That's the lifters that are loose but yes that's how I adjust them on the Kohlers, I suppose someday I should adjust the lash on my 520s, (if ain't broken i ain't fixed it yet) but even on my solid lifter SBC I would rotate the engine over until the pressure is completely off the rocker before adjustment.