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mikeeyre74

Onan P220 keeps cutting out, I've checked....

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Posted (edited)

 I know this topic has been covered million times, and I have researched a lot of it. I am missing something though and I can’t figure it out.  It’s a 1994 possibly a 96 model 520 H and has the Onan P220G  Engine in it. It ran fine all summer long since I’ve had it from a couple of different owners, but while blowing snow twice now, it just cuts out after about five minutes or so. It will restart immediately and run for another 30 seconds.  If I drop the throttle to an idle, it won’t stall out completely and eventually gets going again and we play that game over and over until I get the driveway cleared. 

 

 So far, I know that has good fuel delivery, the battery is new, I’ve checked the continuity of the coil on both tests that I have seen written about... across the primary, and across the secondary, and everything appears in range.  I have done the static timing test, and See 1.4 V or so switching to battery voltage when the flywheel comes around to the timing mark.  Both of my spark checkers when installed show that I have good constant spark for both cylinders.  I am slowly working my way through the troubleshooting manual on this, and am gearing up to pull the flywheel off to see what it looks like underneath there… Can anyone think of anything else I should check if this doesn’t pan out? 

Edited by mikeeyre74

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 I got the flywheel off, and took a few pictures while I was in there. I’m not really sure what to do next? It doesn’t really look all that bad. 

 

Ignition module check

 

Ignition module check

 

Ignition module check

 

Ignition module check

 

Ignition module check

 

Ignition module check

 

 Can anyone think of anything else I need to do while I’m in here?

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Maybe the gas cap vent is pluged and causing a vacum on the cas tank. Side note I would get rid of the Fram oil filter, not a big fan of Fram they are not what they were in the past. NAPA , Wix a better choice IMHO.

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mike

how about an intermittent open circuit on the 9 pin connector?

 

ALSO, it sure will not hurt to clean the inside of the flywheel.

 

thank you. boomer

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In extreme cold, there is a possibility of condensation freezing in the pulse hose to the fuel pump.  If you find any moisture or milky substance, do an oil change.

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Thanks for the ideas, fellas. Here’s some more feedback: 

 

i loosened up up the gas cap after it started to happen to see if it was getting vapor locked up from that. It still kept stalling out. 

 

 There is no nine pin connector anymore, they have all been removed from the connector and connected  directly and shrink wrapped.  The previous owner did this when the connector failed.

 

 I have since cleaned up everything I can get my hands on now that I’m in here, and nothing will go back together gross like this. 

 

 The only thing in the pulse hose is a little bit of oil… Is that unusual? I’m not sure how these things work other than on vacuum, but it does drip a little bit of oil out of there? 

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I would replace the module while it is apart. They can sometimes intermittently cause problems and it's a pain to put back together and take apart again to replace it later. I got one on ebay:

https://www.ebay.com/itm/NEW-REPLACES-ONAN-P-MODEL-IGNITION-MODULE-REPLACES-166-0785-FREE-SHIPPING-/362100971033?hash=item544ee65619

Here is the seller's description:

THIS REPLACES ALL THE OLD SOLID STATE  TYPE IGNITION MODULES ON MOST ONANS INCLUDING P WITH SOLID STATE IGNITION ONLY THIS WILL NOT WORK  WITH POINTS IGNITIONS  ENGINES.  THIS IS OUR NEW DESIGN IT FIRES WITH LESS MAGNETISM AND GIVES A STRONGER PULSE TO THE COIL.

Here are some links to my repairs:

 

 

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Posted (edited)

Well,  I think I’m onto something here, I believe it is a fuel issue.

 

I took everything apart and cleaned it, then put everything back together, and it fired right up. Ran around the driveway have a couple laps until it died. Then, I started it back up and brought it back inside near the air compressor… Then when it started to die out, I used very low pressure in through the gas fill hole in the tank and it fired right back up. To fill speed. Figuring there was a bunch of crap in the fuel tank, I rigged up a gravity feed tank that I strapped to the hood and then started the machine back up, using the fuel pump I figured, to empty the fuel in the tank into a spare gas can so I could clean it out.… Which seemed to work like a champ for a while… Then the fuel pump just stopped working. The engine was running at full RPM, and the fuel just stopped coming out. I can throttle down to an idle and then will pick right back up and start pumping again… What am I missing here?  Why would the fuel pump work at idle, but not at higher RPM for more than 30 seconds or so? 

Edited by mikeeyre74

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I had a fuel pump issue a few winters back with the P216G Onan while throwing snow with my 416-8.  A fuel pump replacement cured it.  What I would try is to gently warm the fuel pump with a hair dryer to see if it makes any difference.  

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Ok. Further inspection shows that my fuel pump has been contaminated with oil. It came through the pulse hose and jammed up the works. I’ve cleaned it out and it seems to be working ok now? But why would it pull oil through the pulse hose like that?

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Posted (edited)

Pump is weak???.  I would try an electric fuel pump.  Best thing I did to my two 520Hs.  No more heavy cranking to start.

Edited by Kurt-NEPA

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15 minutes ago, mikeeyre74 said:

Ok. Further inspection shows that my fuel pump has been contaminated with oil. It came through the pulse hose and jammed up the works. I’ve cleaned it out and it seems to be working ok now? But why would it pull oil through the pulse hose like that?

Have you ever has the crankcase breather apart to clean? The 5/8-3/4" hose coming up through the air cleaner goes down between the cylinders next to the intake kinda a PITA to to get at but there's steel wool mesh wadded up in there that needs to be cleaned with Brakeclean ect dried out and replaced every couple hundred hours, Jeff.

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Posted (edited)
24 minutes ago, mikeeyre74 said:

Ok. Further inspection shows that my fuel pump has been contaminated with oil. It came through the pulse hose and jammed up the works. I’ve cleaned it out and it seems to be working ok now? But why would it pull oil through the pulse hose like that?

 

The pulse hose is connected to the crankcase.  Oil is flying around in there.  Maybe its just a slow pick up over time.  If it works now, just keep an eye on it.

 

Good to see you got it working.

 

Jeff has a good theory on the breather.

Edited by Kurt-NEPA

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So that was the solution! I just ran it for a while and it worked like a champ.  

 

I DID have the breather apart when I did the valve adjustment a couple months ago and it was all cleaned out... I’m not sure how it got that oil all up in there but I will say that it was dirty, black colored oil, not clean oil like I have in the engine now. It must have been some carryover from the previous owner that was stuck somewhere and got dislodged in there somehow?

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And yet here it is again.. cleaning up the driveway this afternoon after all the drifting snow we're getting and she starts cutting out again. It's the same thing, oil in the pulse pump line. Took it apart and blew out the lines again. Heard the oil gurgling in the line as I blew it out. 

 

Pulled the crank case breather apart on the top and it's still clean as a whistle, with all the balls in place and loose, doing what they're supposed to, and the SS mesh all clean. The oil level is between the lines, right smack in the middle of the hash marks. What gives? Where am I going wrong?

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What weight oil are you running, I know it doesn't seem logical but straight 30W may to be vs 5or10W30 in these temps may be causing your issue as well a faulty filter I prefer to use the Cummins/Onan filters others NAPA/WIX I stay away from Fram ,just trying to help out here, Jeff.

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I believe I have 10w-30 in there now. I don’t follow what you mean tho. I think spell check jumped on your case there... “may to be” what? 

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Re: post #11       Kurt-NEPA,  I'm curious what pump did you use?

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8 hours ago, Squawk said:

Re: post #11       Kurt-NEPA,  I'm curious what pump did you use?

I used an Airtex E8016S Universal Electric Fuel Pump

 

https://www.amazon.com/gp/product/B000C1LW0E/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1

 

I'm running three of them.  2 on 520H's and one my 520xi.  Oldest one is 3 years old and they have been flawless.  I did wire them up with a relay. 

 

All three of these tractors were draining gas back to the tank whenever they sat for a couple of days.  Then I would have to crank forever to get fuel into the carb.  Now I turn the ignition on for a few seconds until I hear the pump labor a bit when the carb bowl is full and start her up.  Works great.  The hard part of this is finding place to mount the pump.

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If you let the engine off for five minutes and then restart, does it run right for awhile?  If it does, perhaps the ice has melted during the hot soak.  If it is starving for fuel, it is either water in the pulse line freezing, a faulty fuel pump or bad fuel lines.  If there is excess moisture in the oil or gasoline, drain and replace.

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15 hours ago, mikeeyre74 said:

I believe I have 10w-30 in there now. I don’t follow what you mean tho. I think spell check jumped on your case there... “may to be” what? 

May be causing your oil in the pulse pump line, if the oil is too thick or the oil filter doesn't have the proper media/valves like the factory version, also years ago when blowing snow on my first 520 I noticed the fuel pump icing over, to help remedy this got a piece of the thick foam water pipe insulation from Lowe's ect that is pre-split long enough to cover the lines and zip tied it on during the winters no more iced/frozen fuel pump, now with the cab it's not an issue anymore, Jeff.

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