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Onan P218

Posted: Wed Mar 01, 2023 10:23 am
by TLD89
I decarb and set values, now motor turns over with spark and fuel and backfires. But does not run. Not sure that I turned the motor clockwise when setting values. Could that be the problem?
When setting values I set them at BTC should I've set them at 20 degrees?

Re: Onan P218

Posted: Wed Mar 01, 2023 10:37 am
by Eugen
TLD89 wrote: Wed Mar 01, 2023 10:23 am I decarb and set values, now motor turns over with spark and fuel and backfires. But does not run. Not sure that I turned the motor clockwise when setting values. Could that be the problem?
Might help to give a little more context about this engine. Was there a problem at all before, did it work at all?

If you set the valve clearance properly I don't think it matters which way you turn the engine to get to TDC. For backfires timing is a usual culprit. But the fact that you touched the valves, that may be involved in it too.

Re: Onan P218

Posted: Wed Mar 01, 2023 11:43 am
by DavidBarkey
TLD89 wrote: Wed Mar 01, 2023 10:23 am I decarb and set values, now motor turns over with spark and fuel and backfires. But does not run. Not sure that I turned the motor clockwise when setting values. Could that be the problem?
When setting values I set them at BTC should I've set them at 20 degrees?
Yes , What Eugen said . Need more background.
How did it run before ? Why did you adjust the valves , were they out of spec ? What all did you do to the engine ? Does it back fire out the exh. or the carb ?

Re: Onan P218

Posted: Wed Mar 01, 2023 4:05 pm
by TLD89
Eugen wrote: Wed Mar 01, 2023 10:37 am
TLD89 wrote: Wed Mar 01, 2023 10:23 am I decarb and set values, now motor turns over with spark and fuel and backfires. But does not run. Not sure that I turned the motor clockwise when setting values. Could that be the problem?
Might help to give a little more context about this engine. Was there a problem at all before, did it work at all?

If you set the valve clearance properly I don't think it matters which way you turn the engine to get to TDC. For backfires timing is a usual culprit. But the fact that you touched the valves, that may be involved in it too.
The motor ran before with the choke partly closed. I think it had a carb issue, so I cleaned the carb and sealed the intake manifold seam.

Re: Onan P218

Posted: Wed Mar 01, 2023 4:22 pm
by TLD89
TLD89 wrote: Wed Mar 01, 2023 4:05 pm
Eugen wrote: Wed Mar 01, 2023 10:37 am
TLD89 wrote: Wed Mar 01, 2023 10:23 am I decarb and set values, now motor turns over with spark and fuel and backfires. But does not run. Not sure that I turned the motor clockwise when setting values. Could that be the problem?
Might help to give a little more context about this engine. Was there a problem at all before, did it work at all?

If you set the valve clearance properly I don't think it matters which way you turn the engine to get to TDC. For backfires timing is a usual culprit. But the fact that you touched the valves, that may be involved in it too.
The motor ran before with the choke partly closed. I think it had a carb issue, so I cleaned the carb and sealed the intake manifold seam.
The values did have carbon build up and where a few thousands off. I did take the timing gear cover off carefully cleaned the stator.

Re: Onan P218

Posted: Wed Mar 01, 2023 5:38 pm
by DavidBarkey
TLD89 wrote: Wed Mar 01, 2023 4:05 pm
Eugen wrote: Wed Mar 01, 2023 10:37 am
TLD89 wrote: Wed Mar 01, 2023 10:23 am I decarb and set values, now motor turns over with spark and fuel and backfires. But does not run. Not sure that I turned the motor clockwise when setting values. Could that be the problem?
Might help to give a little more context about this engine. Was there a problem at all before, did it work at all?

If you set the valve clearance properly I don't think it matters which way you turn the engine to get to TDC. For backfires timing is a usual culprit. But the fact that you touched the valves, that may be involved in it too.
The motor ran before with the choke partly closed. I think it had a carb issue, so I cleaned the carb and sealed the intake manifold seam.
Lean can also cause back fires up the carb . Check your fuel supply to the carb for restrictions. Do a compresstion test to rule out valves issues as well .

Re: Onan P218

Posted: Sat Mar 11, 2023 7:43 pm
by TLD89
TLD89 wrote: Wed Mar 01, 2023 10:23 am I decarb and set values, now motor turns over with spark and fuel and backfires. But does not run. Not sure that I turned the motor clockwise when setting values. Could that be the problem?
When setting values I set them at BTC should I've set them at 20 degrees?

Still have the issue with starting. I checked timing with timing light and the timing mark TDC on flywheel is not even close to the TDC on the timing gear cover, it is at about 8 o'clock. The flywheel is in the correct position with the keyway on the shaft.
When decarbing nothing was touched with the cam or crank gears, only took timing gear cover off to retrieve value keeper. The governor linkage is also installed correctly.
Changed ignition module with a used one I had still have the same problem. Any ideas ?

Re: Onan P218

Posted: Sat Mar 11, 2023 9:11 pm
by Spike188
You have me stumped on the timing issue. If the timing cover was off, conferming that the cam and crankshaft gear timing marks line up would be a first check. The ignion module position is another thought. Dave may have some ideas.

Re: Onan P218

Posted: Sat Mar 11, 2023 9:52 pm
by Jancoe
How about checking float height on your carb? Are you pushing to much gas through the carb?

Sent from my SM-S906U using Tapatalk


Re: Onan P218

Posted: Sun Mar 12, 2023 8:08 am
by DavidBarkey
For it to be that far out . The trigger ring has to be on backwards or not on the key properly some how .

Re: Onan P218

Posted: Sun Mar 12, 2023 8:22 am
by TLD89
Thanks Dave I will check the trigger ring this morning.
DavidBarkey wrote: Sun Mar 12, 2023 8:08 am For it to be that far out . The trigger ring has to be on backwards or not on the key properly somehow .

Re: Onan P218

Posted: Mon Mar 13, 2023 7:05 am
by TLD89
TLD89 wrote: Sun Mar 12, 2023 8:22 am Thanks Dave I will check the trigger ring this morning.
DavidBarkey wrote: Sun Mar 12, 2023 8:08 am For it to be that far out . The trigger ring has to be on backwards or not on the key properly somehow .

You were right Dave. Thanks again for your help!

Re: Onan P218

Posted: Mon Mar 13, 2023 7:27 am
by DavidBarkey
TLD89 wrote: Mon Mar 13, 2023 7:05 am
TLD89 wrote: Sun Mar 12, 2023 8:22 am Thanks Dave I will check the trigger ring this morning.
DavidBarkey wrote: Sun Mar 12, 2023 8:08 am For it to be that far out . The trigger ring has to be on backwards or not on the key properly somehow .

You were right Dave. Thanks again for your help!
:O don't tell the :wife: , she will expect it all the time . :rofl: :rofl:
:congrats: :thumbsup: Glad you got it sorted out . Which was it ? On back wards or not on the key properly ?

Re: Onan P218

Posted: Mon Mar 13, 2023 8:49 am
by TLD89
DavidBarkey wrote: Mon Mar 13, 2023 7:27 am
TLD89 wrote: Mon Mar 13, 2023 7:05 am
TLD89 wrote: Sun Mar 12, 2023 8:22 am Thanks Dave I will check the trigger ring this morning.


You were right Dave. Thanks again for your help!
:O don't tell the :wife: , she will expect it all the time . :rofl: :rofl:
:congrats: :thumbsup: Glad you got it sorted out . Which was it ? On back wards or not on the key properly ?
Not keyed properly. This being in the wrong position cause the rectifier to fail?

Re: Onan P218

Posted: Mon Mar 13, 2023 9:50 am
by DavidBarkey
TLD89 wrote: Mon Mar 13, 2023 8:49 am
DavidBarkey wrote: Mon Mar 13, 2023 7:27 am
TLD89 wrote: Mon Mar 13, 2023 7:05 am

You were right Dave. Thanks again for your help!
:O don't tell the :wife: , she will expect it all the time . :rofl: :rofl:
:congrats: :thumbsup: Glad you got it sorted out . Which was it ? On back wards or not on the key properly ?
Not keyed properly. This being in the wrong position cause the rectifier to fail?
I doubt that , More than likely age , short to ground or trying to charge a dead battery . Charging systems on these are maintainers not full on battery chargers .

Re: Onan P218

Posted: Mon Mar 13, 2023 3:59 pm
by ssmewing
TLD89 wrote: Mon Mar 13, 2023 8:49 am
DavidBarkey wrote: Mon Mar 13, 2023 7:27 am
TLD89 wrote: Mon Mar 13, 2023 7:05 am

You were right Dave. Thanks again for your help!
:O don't tell the :wife: , she will expect it all the time . :rofl: :rofl:
:congrats: :thumbsup: Glad you got it sorted out . Which was it ? On back wards or not on the key properly ?
Not keyed properly. This being in the wrong position cause the rectifier to fail?
You can fry a rectifier instantly if the engine runs and the rectifier is not grounded.