cdahl383
ArboristSite Operative
Sweet! Didn't even notice that haha! I'll see if I can find one somewhere nearby without having to use Ebay.
Pioneer 620 - Won't rev up clean to full throttle
- Thread starter cdahl383
- Start date
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cdahl383
ArboristSite Operative
I just went back out and put the carb back on the saw. Brought it outside and fired it up. Started within a couple pulls and idled great. Revved it up and it revved good. Revved it up to full throttle and it revved up pretty good without any issue. Ran good and idled for a while. I made a few adjustments and it ran fine.
Then, just like last time, as it was sitting there idling after it had gotten warmed up, you could hear the tone of the engine change. Almost sounded like it was running leaner or something. I tried to rev it up and it just bogged down. It idled for a bit and then got worse and then eventually it started to stumble and crapped out on its own. Same thing it did just a few hours earlier today.
Sure seems like it's ignition related. If it were the carb, why would it run fine at first and then run crappy and die out? It would just run like crap all the time.
It starts to run rough and die when it gets warmed up. Must be that condenser or coil failing. It's probably all the original stuff from 60 years ago.
I'll find a condenser first and if that doesn't work then I'll look into getting a new coil. At some point this thing has to run right haha!
Then, just like last time, as it was sitting there idling after it had gotten warmed up, you could hear the tone of the engine change. Almost sounded like it was running leaner or something. I tried to rev it up and it just bogged down. It idled for a bit and then got worse and then eventually it started to stumble and crapped out on its own. Same thing it did just a few hours earlier today.
Sure seems like it's ignition related. If it were the carb, why would it run fine at first and then run crappy and die out? It would just run like crap all the time.
It starts to run rough and die when it gets warmed up. Must be that condenser or coil failing. It's probably all the original stuff from 60 years ago.
I'll find a condenser first and if that doesn't work then I'll look into getting a new coil. At some point this thing has to run right haha!
cdahl383
ArboristSite Operative
Ordered a new condenser. Should be here by the weekend hopefully. Looks like I'll be popping the flywheel off yet again!
I got a new set of points too since they were only $12. I might just replace both the points and condenser together so both are new and keep the old points as a spare set since I know they still work.
I got a new set of points too since they were only $12. I might just replace both the points and condenser together so both are new and keep the old points as a spare set since I know they still work.
Make sure to clean the new points. Sometimes they have a protective coating.
What kind of tank vent does it have? Try loosing the cap when it starts to stumble
cdahl383
ArboristSite Operative
What would you clean them with? Would 1000 grit sandpaper work? Don’t want to scratch them up too much.
cdahl383
ArboristSite Operative
I checked that. I unscrewed the cap and it ran the same.
Probably just contact cleaner and you can check for continuity before you install them.
cdahl383
ArboristSite Operative
Ok, I'll keep that in mind when installing them.
Do you think it's possible I'm overlooking something in the fuel system? I thought of a possible restriction in the fuel line or filter or sucking air in the fuel line between the sediment bowl and carb, etc. But if that were the case, wouldn't the saw run crummy all the time, not just when it gets warm after several minutes of running? Just want to make sure I'm not overlooking something simple there.
Hopefully the new points/condenser is all it is at this point.
altatim
ArboristSite Operative
I might have a carb if you need one, I'll have to look though
cdahl383
ArboristSite Operative
Ok, mine is a Tillotson HL22A.
I don't think it's a carb issue at this point as I've cleaned the hell out of the thing and it has all new parts in it, but who knows.
altatim
ArboristSite Operative
Sounds good, I have a 650 with a good carb and I know a fellow with a few 600, 620, 650 saws that are for parts that I should be able to get a carb from.
The best way to completely rule it out is to use a known good carb.
cdahl383
ArboristSite Operative
Sweet. Keep me posted!
cdahl383
ArboristSite Operative
Right. Maybe I can pick up a carb from the guy on this thread, or I can swap carbs from that Pioneer 600 that I'm supposed to pick up in a few weeks. I don't know if the 600 has the same carb, but I'm assuming so.
In the meantime I can try the condenser/coil and see if that makes any difference.
The 600 uses the same HL22A carb
cdahl383
ArboristSite Operative
Sweet! Good to know!
Did you try readjusting the idle? The idle is affected by residual fuel lurking in the crankcase and the first time you run the saw at full throttle for awhile it cleans out the crankcase and the idle may need to be set again.
From your description, it seems to run good on the high speed fuel, just stumbles and dies when sitting at idle after the WOT run, a sign that it is now too lean at idle. If the saw runs at full throttle and full load (have to cut something) you do NOT have a problem with fuel delivery.
Do some testing, when it stops is the plug wet or dry and test for spark when it quits.
From your description, it seems to run good on the high speed fuel, just stumbles and dies when sitting at idle after the WOT run, a sign that it is now too lean at idle. If the saw runs at full throttle and full load (have to cut something) you do NOT have a problem with fuel delivery.
Do some testing, when it stops is the plug wet or dry and test for spark when it quits.
cdahl383
ArboristSite Operative
Yes. Once it started running goofy, I tried to adjust the low speed screw but it seemed to have no effect. When I first started the saw up it ran good and the low speed screw did affect how the engine ran. It kind of sounds like it's too lean, but no matter what you do it doesn't seem to affect it. I really think it has to be an ignition issue at this point, like something is failing once it gets warmed up.
It wasn't running at full throttle before, but it seems like after I cleaned out the high speed channel it would rev up good. It's just that now after it warms up it starts running poorly and then dies. Let it sit for a bit and it'll start right back up and run good again.
When it starts running rough, if I try to rev it up again to full throttle, it just bogs down and almost dies.
I agree, I don't think there is a fuel delivery problem at this point. I think there's something else going on.
I'm going to start with the condenser / points and if that doesn't work I'll try replacing the coil. It's clearly getting fuel as I verified that when the carb was apart spraying stuff through the ports. It has great compression. It has to be something with the ignition system. All the stuff in there appears to be original, which means it's over 60 years old. Probably time to replace some of that stuff.
Last time when it crapped out, I pulled the plug and it was pretty dry. Maybe a little fuel residue on there, but looked like a normal plug for the most part.
