P220g on 520H Smoking

[TC10284 113]

Alright guys, I'm going to let the pics and videos do most of the talking here. I'll just explain the pics/videos.

https://photos.app.goo.gl/UN3KbKprx6G8NbaF7

 

First 5 pics in this link are of the rear plug and rear cyl compression reading. 

You can also see the oil on the plug threads and my finger when handling it. 

 

Next three pics are the front plug and front cyl compression reading. 

 

First video is of it running with those same plugs. 

 

Next two pics are of just a few more pics of the rear plug after it ran.

 

Next video is of an in-line spark tester on rear plug. 

 

Next video is of an in-line spark tester on front plug. 

 

Next two pics is of a working NGK TR5 (minimally used) plug and the oil after trying it in the rear cyl for a minute. 

 

Next pic is of two new NGK TR4 plugs I put in. 

 

Next video is of it running on those same two new plugs. 

 

Next video is of a jumper wire ran from battery positive to coil positive. Same poor performance. 

 

Last two videos are just additional videos.

 

 

At this point, to me it seems like it is running super-rich basing on the exhaust and poor performance. This carb is SUPPOSED to be good and clean AND supposed to be the original one. I believe the carb that is supposed to go on it (the one on it now) has an accelerator pump and the one I had on it previously does not. But with either carb, it runs like crap, or runs good and then starts sputtering and then dies. I will probably just clean the previous carb since it ran a bit better and try it again. I also have an off-brand Chinese one I can try too. 

Although, something still is not right here...  

 

A note on the plugs...
I know that it is supposed to have an equivalent plug of an NGK TR5, which is what I use in my other 520-H's. I have tried both TR5 and TR4 plugs in this thing and it seems to foul either, or whatever the issue is, it's happening with both types. 

Edited May 24, 2020 by TC10284

[lynnmor 7,817]

That thing really is sick!  You have far greater problems than carburetor and spark plugs with all that mechanical noise.  I noticed that the vacuum gauge is reading near 100%. if it is functioning properly low vacuum is often the sign of ignition timing being way off.  It is possible to have normal compression and still have loose valve seats or broken oil rings.   Did you clean the breather that is next to the carburetor and reassemble it properly?    You can see the timing marks if you pull the large rubber tube that sticks in the air cleaner housing if you want to check that.  A timing light will work or you can watch for spark as you rotate the engine in the normal direction by hand.  After those checks, I would be pulling that puppy down.

[TC10284 113]

28 minutes ago, lynnmor said:

 Did you clean the breather that is next to the carburetor and reassemble it properly?

Pretty sure I have before but I can check it again when I take the carb back off. 

 

What's strange is that with the other carb it runs fine a while and then starts to sputter/die after a while. 

 

For checking the timing, this is getting above my current knowledge level so I may be a bit needy on that part. 

I'm looking at the p220g service manual here on page 8-2 which seems pretty straightforward, so I'll try that as soon as I can and report back. 

https://manuals.casecoltingersoll.com/ServiceManuals/Onan Service Manual 965-0762_watermarked.pdf

 

I'm looking at this timing light too:

https://smile.amazon.com/Houkiper-Automotive-Ignition-Inductive-Motorcycle/dp/B07NVCZQ5G/ref=sr_1_1?dchild=1&keywords=small+engine+timing+light&qid=1590364057&sr=8-1

 

 

Edited May 24, 2020 by TC10284

[lynnmor 7,817]

On page 8.2 in the manual you linked to is a procedure for checking timing using a volt meter.  You are just trying to see if the ignition trigger has moved or the flywheel key has a problem.  Thinking about this, perhaps you should investigate the key.  If all that smoke is fuel, the carburetor would have to be very bad, but if that is the case, vacuum would be low from that as well.  Videos can come across sounding way different, but that knocking noise is troubling.

 

 

[TC10284 113]

Here is the timing test results. 

https://photos.app.goo.gl/n75awGe1hFzRL5mE8

 

Thanks for sticking with me also. Couldn't do it without you guys... 

[TC10284 113]

After cleaning the previous carb and  swapping it back to the engine. 

https://photos.app.goo.gl/9qZxzufTd6uqGbQUA

 

Oh and I checked the breather. It looked clean.

https://photos.app.goo.gl/RKWSMTEyvf3YZeDH9

 

I also replaced the exhaust gaskets and intake gaskets that looked somewhat rough but not completely bad. Just in case... 

 

I have yet to run it and see if it'll start sputtering and die out. Might do that after I eat. 

Edited May 25, 2020 by TC10284

[TC10284 113]

Alright so I just tested it out. Drove from back of my property to basement with garden trailer to pick up boxes and take to road. Drove back to the back side of property. Disconnected trailer. Maybe 1500ft total. 

Then did a test mow. Got a few stripes in. Started surging slightly. Could see vacuum go to 100% then drop back To 80%. Half a stripe later, backfired twice and she died. 

Will not start except for just a second at full choke but dies. I can probably let it sit and it will start up again later. 

[lynnmor 7,817]

Couple of things:

 

That air filter is a wreck.

 

The white smoke must be coming from worn valve guides, intake valve seals or worn piston rings, but first are you running fresh gasoline without snake oil in it?

 

Since the intake manifold is still dirty, perhaps you missed a leak in it.

 

The engine dying after your short run may have come from fuel starvation caused by a dirty tank valve & screen, bad fuel line, bad fuel pump or bad pulse line on rear of fuel pump.

 

So remove gas tank valve and clean it.  Rinse the tank with fresh gas.  Don't let that air filter within six feet of an engine.  Don't use additives except for long term fuel storage.  Replace all fuel line, fuel filter and pulse line.  The pulse line is a miserable job so don't do it till last but do check it as best you can.

[TC10284 113]

2 hours ago, lynnmor said:

Couple of things:

 

That air filter is a wreck.

 

The white smoke must be coming from worn valve guides, intake valve seals or worn piston rings, but first are you running fresh gasoline without snake oil in it?

 

Since the intake manifold is still dirty, perhaps you missed a leak in it.

 

The engine dying after your short run may have come from fuel starvation caused by a dirty tank valve & screen, bad fuel line, bad fuel pump or bad pulse line on rear of fuel pump.

 

So remove gas tank valve and clean it.  Rinse the tank with fresh gas.  Don't let that air filter within six feet of an engine.  Don't use additives except for long term fuel storage.  Replace all fuel line, fuel filter and pulse line.  The pulse line is a miserable job so don't do it till last but do check it as best you can.

 

Yeah, I realize the air filter is bad. Was hoping to hold off on replacing it until it ran better. I will swap it just in case. 

 

As for fuel, the only thing I've had in the fuel is MMO. However, I have already drained and flushed out the fuel tank. It had a lot of trash in it. It does not have a screen on it anymore. I've put a new fuel pump on it as well. It also has a fairly new fuel shut off. And new fuel filter. 

So, it has fresh gas mixed with gas that has MMO in it. 

 

As for the intake, I have gone over it already and sealed it with gasket maker around the edges. It looks like crap but it has worked on others I have (so far). 

 

I can run a temp fuel line and see if that helps. The line was kind of gummy when I replaced the fuel shut off. 

 

I'm starting to wonder if I have a bad rotor or ignition module, even though I've replaced them. Could a bad stator cause similar? 

 

 

[lynnmor 7,817]

1 hour ago, TC10284 said:

 

I'm starting to wonder if I have a bad rotor or ignition module, even though I've replaced them. Could a bad stator cause similar? 

 

Since you are getting so much smoke and black spark plugs I doubt that it is ignition related.  That gummy fuel line might be adding junk to the carb, I would replace it.  I still think you have an engine in need of internal repairs and tuning will only do so much.  Obviously the fuel and ignition systems need to be working properly regardless of the mechanical condition of the engine.  What ever you do, lose the snake oil gas and run it on unadulterated fuel, adding oil can only make it smoke more, upset the mixture and foul the plugs.  There is no such thing as a mechanic in a can.

[TC10284 113]

On 5/25/2020 at 9:41 PM, lynnmor said:

Since you are getting so much smoke and black spark plugs I doubt that it is ignition related.  That gummy fuel line might be adding junk to the carb, I would replace it.  I still think you have an engine in need of internal repairs and tuning will only do so much.  Obviously the fuel and ignition systems need to be working properly regardless of the mechanical condition of the engine.  What ever you do, lose the snake oil gas and run it on unadulterated fuel, adding oil can only make it smoke more, upset the mixture and foul the plugs.  There is no such thing as a mechanic in a can.

Replaced the fuel line with new/fresh hose. 

No dice. Got half a stripe before it shut off. Just flat died. Knew it would because it sounded sputtery and then fine, then sputtery again, then fine - prior to taking off. 

Engine to now be removed and repowered. Possibly repair while off. 

Most frustrating one so far...

Edited May 30, 2020 by TC10284