Stumped Partner

[Jeff Lary]

Hi all I have a Partner 5000 that has a severe starting issue and I need some fresh thoughts. I am embarrassed to admit it but I am stumped.

This particular saw has been a pima for a long time. I have dealt with a poor start issue for 2 years now.
So I will make this as short as I can .I have notes on this saw going back to 2015 every notation I have made includes a poor starting issue. Yesterday it happened again I bet it took 50 pulls to get it started. I took it into my shop this morning to see what I could find. I had been changing plugs around to get one that fired ,better than the rest.... So I got to thinking maybe I had a bad or weak coil.
I had some spare coils and changed it and also re-gapped the plug . Turns out the plug in the saw was gapped at about 20 tho the spark was anemic at best so I re-gapped it to 35 tho. and now it is bright purple and strong so I was very impressed with myself.
I re-set the air gap of the coil to flywheel and sanded the coil pickups and the flywheel magnets and set the aig gap to 10 tho but I think that had been done already last winter. But in any case on the first pull it popped and started right up by the third pull.
I was very happy figured I had solved the issue. I also pulled the gas filter and blew compressed air backwards through it cleaning it out but it seemed fine to begin with.

I took it to the woods it started right up I sawed up a 50' beach tree limbs and all it ran stellar!!. I was very satisfied. I shut the saw off to load the rounds on my trailer and needed to finish up maybe a 2 inch cut so I grabbed the saw.... I must have pulled it over 50 times not even a hint of a pop. I pulled the plug bright fire but dry as a popcorn fart not even a hint of gas on it. I never got it re-started.

How could the saw run so great for 30 minutes then all of a sudden not get any gas at all?. Well the gas tank was low on fuel and I did recut the gas line to make a good connection to the filter.... so maybe it could not suck any gas from the tank? So I filled it up with gas and pulled it another 30-40 times and nothing I gave up and came home.

The carb on it was rebuilt last winter when I went through another bad spell with it. I guess I could re-build it again that is all I can think to do. I checked the compression it is at 185#. How can it run so well then not at all ????

If you have any advice I will gladly listen it has new crank seals as of 2015 too..... The impuls grommet was replaced as well but I have more and could do it again if need be I am o-p-e-n- to suggestions ha ha have a nice Labor Day Jeff

 

[LoveStihlQuality]

Pressure and vac test. Timing off?

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[Jeff Lary]

I don't think the timing is off the saw ran flawlessly for a 1/2 hour or more. I do have a brand new OTC leak down tester but again I am embarrassed to admit I have no idea how to use it as I never have ha ha. I bought it new last year and never tried it.
The saw was sitting on my lawn since I came out of the woods earlier today, and I just noticed it was starting to rain, so I went out to grab it and put it away. For the heck of it I put on the choke and pulled it 3 times and it sat right there and idled........ WTH do you make of that??

All I can think of is maybe the pump diaphragm is weak?? and sitting for 3 hours the fuel had time to seep up the line putting it closer to the carb ...if it was low when I shut it off earlier in the woods when I stopped cutting.
How can this saw heal itself just by sitting for 3 hours? It is not electrical ,..as the moment I gave up on trying to start it in the woods 3 hours ago I pulled the plug to check for fuel and fire. It was firing excellent but was bone dry as far as gas on the plug electrode??? It should have been flooded I must have pulled it 10 times with the choke on.

 

[LoveStihlQuality]

Tank vent? Did you say you replaced fuel line?

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[Jeff Lary]

No I didn't replace the line,.. I need to buy some I am all out. The tank vent seems to be ok but I can check it on this saw it is pretty simple. A short tank vent grommet goes into the top of the tank. Then a filter looking gadget goes into the line. The at the other end of the gadget a maybe 3 inch length of fuel line leaves the filter gadget and that's it pretty much.

 

[procarbine2k1]

I'd go back through the carb. Or swap it with another.
As you said, the plug was dry... It's not getting fuel. If the line is good, and you are getting fuel to the carb, the carb has to be the problem. I'd be curious to see what the inlet screen looks like inside, and what it looks like behind it.

 

[Jeff Lary]

Tomorrow ,
I agree it must be a carb issue, I have another that I used the ultrasonic cleaner on last winter then rebuilt it. I will tear into the one that is on it now then replace it with the newly rebuilt cleaned one. The one on it now was also ultrasonically at the same time and freshly rebuilt too.
I will take a picture of the insides if there is anything to see there I hope there will be but I do doubt it. I would like to think the metering lever is too low but I know I just set it last winter and I am very fussy trying hard to get it right. But I will check it all.

 

[Jeff Lary]

Well I am back. I took the carb off and before trading it out for another and I opened it up. There were a hundred or so of the tiniest particles of saw dust on top of the pump diaphragm and also in around the Metering diaphragm as well so there may have been more below?
I took it apart completely washed every port with carb cleaner and air. This carb has a governor on it and I thought I had defeated it long ago but when I removed it,.. the passage below it was still open. So I placed a small piece of gasket material in the opening and screwed the governor back in. I was told many years ago that these can be way more trouble than they are worth and should be defeated when ever I encountered one.

I did discover the metering arm was a little low. When I checked it with the Walbro gauge I could see a little light between the gauge and the arm. So I bent it up till when sliding the gauge back and forth over it I felt it "click" up and over the arm I left it that way.
I put it all back together and it started right up most people would be happy about this outcome but I have had this result many times before.
The real test will be to run it a 1/2 hour or so then shut it off for 10 min then re-start it.
Between the super fine dust in the carb,..s a semi working governor? and a metering arm a little low maybe one of these things will be the magic bullet !

 

[alexcagle]

Sometimes saws do strange things when they get warmed up.
I've seen gas boiling at 95°, causing heat sink, and excess tank pressure.
I've seen newly installed hoses that kink when warmed up on corners. Heat affects pliability and resilience in materials.
I've seen base gaskets that leaked badly as the saw warmed up.
Even hoses that became restricted at through tank holes because of incorrect wall thickness.
....Things to consider....

 

[Jeff Lary]

Yes you are spot on I need new fuel line and ill get some soon. It is just weird ya know starts on 3rd pull today starts on 50th pull tomorrow. I tell ya I kinda wish I knew what it was like to run a saw that was new ha ha. Sometimes I am running one of mine and I am proud that I make it run so well. Sometimes I wonder how far could I throw this saw if I really really concentrate ... My mood varies depending on my fatigue I guess. Yesterday I was over a mile back in the woods when it would not re-start.

 

[albert]

Common on the 500 and 5000 saws. The fuel tank is part of the crankcase, it gets hot. Fuel boils and vapor locks. Some fuels are worse than others. Worse with e10, and warm and hot weather. Letting saw idle for a bit before shutting down and keep it in the shade while off can help. Keep it clean under the covers and make sure your tank vent is 100%. In a pinch you can remove the top cover to let out heat and pour some cool water over fuel tank and carb.

 

[Jeff Lary]

yes I have seen this many times but that day the gas was not boiling. But I have seen it before. It's like if you try to start it hot and It wont start just wait 20 min and I will. I think the gas is not being " pulled" into the carb at times. I am in hopes raising the metering arm slightly will help. I will not know for a while I most likely will not be running it till next Sunday.