Loctite 620 would seal the metal to metal outer ring of an oil seal to the seal bore, with the engine under vac the green will be drawn in to any gaps.
Pioneer 620 - Won't rev up clean to full throttle
- Thread starter cdahl383
- Start date
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cdahl383
ArboristSite Operative
Well it’s got a new seal now. I’ll check it tomorrow and see if it has any leaks.
So that leak wouldn’t cause a problem then? I figured since I found it I might as well fix it.
What’s your take on what the issue is? Carb related still?
I might try popping the Welch plugs off to see if there’s any crud in there.
What about that felt filter in the sediment bowl? Maybe I could remove that just to see if that’s restricting fuel flow?
It really does sound like it’s starving for fuel though. If it had an air leak wouldn’t it just run like that forever? It dies out like it ran out of fuel.
cdahl383
ArboristSite Operative
I’ll keep that in mind for the future.
Is the felt filter in the sediment bowl a new one or older used possibly hardened or partially blocked?. We replaced them every time we removed the glass for cleaning, about once a month back when those saws were our main tools in the woods. I think they came in a bag of 25 from our local dealer.
cdahl383
ArboristSite Operative
It’s the old one that came with the saw. I soaked it in chem dip but maybe it’s just too far gone? I couldn’t find any online at the time so I just left it.
I could remove it temporarily just to see if it makes any difference. I’ve got a new filter in the tank so that should stop most of the crud from getting through.
Sounds like a problem I had on my boat. It idled fine and was ok at low speed but any high and it starved. Fuel filter in the carb was clogged - happened very suddenly. By all means, get that felt out and try it.
I noticed in the video, when you loosened the fuel cap to see if that was causing fuel starvation, you tightened in right back up. You might want to try that again with leaving the cap loose for a few minutes. it takes a little while for the carb to recover the fuel volume under the diaphragm after it's been seriously depleted.
cdahl383
ArboristSite Operative
Ok I’ll keep that in mind. Not sure if I’ll get to mess with it today, maybe tomorrow.
cdahl383
ArboristSite Operative
Installed the new clutch side crank seal on Friday evening since I found it had a small leak between the seal bore and the outer edge of the seal. This time I put some motoseal around the outer edge of the seal before I tapped it in. I also added a small layer of motoseal around the outer edge crevice with a small pick, then smeared it around to smooth it out. Brought the saw inside to cure over the weekend at room temperature since I knew I'd be busy anyway.
Brought the saw back out to the garage today (my wife will be happy now) and did another pressure test. This one was much better. Sprayed soapy water around the crank seal while I had 7psi pumped up into the engine. No bubbles at all anywhere. Looks like it's a perfect seal now.
Watched the Mityvac gauge and it barely lost any pressure this time. After a minute it lost around 0.5psi and by two minutes it was still a little above 6psi (starting pressure was 7psi). There might be a very small leak elsewhere, but I don't think that's going to cause any problems at this point. I'm going to call it good, reassemble the rest of the saw, and move on to other things.
I think I'm going to double check my fuel line routing in the tank. I'm thinking maybe the rubber line I used was kind of stiff, so by bending it to route the filter way at the other end of the tank, it could be lifting the filter up out of the fuel perhaps if it's not completely full. I might just pull that line off and get some larger tygon line that's more flexible and try that. I can always put the rubber line back on if it doesn't make a difference.
I'll remove the felt filter from the sediment bowl and see if that makes any difference as well.
If none of that helps, I may try popping off the welch plugs in the carburetor just to rule that out too.
I took the fuel cap apart and it looks like it's clean and assembled properly per the parts diagram I have. But I'll try unscrewing that as well when it's running to see if that makes a difference.
Beyond that, I think the fuel system is pretty much covered. I'd really like to get my hands on a spare HL22A carb though just to rule out that mine isn't goofed up somehow.
If none of that helps, I may have to just move on to the ignition system. Perhaps the condenser is causing weak spark once it's warmed up? Coil going bad?
At this point, all I can do is just make a list of things to try, and then start marking them off one by one as I do them. At some point, I'll find the issue. Hopefully I find it sometime this year though haha!
Here's a quick video I made earlier today when I did another pressure test to check the new seal I installed:
Brought the saw back out to the garage today (my wife will be happy now) and did another pressure test. This one was much better. Sprayed soapy water around the crank seal while I had 7psi pumped up into the engine. No bubbles at all anywhere. Looks like it's a perfect seal now.
Watched the Mityvac gauge and it barely lost any pressure this time. After a minute it lost around 0.5psi and by two minutes it was still a little above 6psi (starting pressure was 7psi). There might be a very small leak elsewhere, but I don't think that's going to cause any problems at this point. I'm going to call it good, reassemble the rest of the saw, and move on to other things.
I think I'm going to double check my fuel line routing in the tank. I'm thinking maybe the rubber line I used was kind of stiff, so by bending it to route the filter way at the other end of the tank, it could be lifting the filter up out of the fuel perhaps if it's not completely full. I might just pull that line off and get some larger tygon line that's more flexible and try that. I can always put the rubber line back on if it doesn't make a difference.
I'll remove the felt filter from the sediment bowl and see if that makes any difference as well.
If none of that helps, I may try popping off the welch plugs in the carburetor just to rule that out too.
I took the fuel cap apart and it looks like it's clean and assembled properly per the parts diagram I have. But I'll try unscrewing that as well when it's running to see if that makes a difference.
Beyond that, I think the fuel system is pretty much covered. I'd really like to get my hands on a spare HL22A carb though just to rule out that mine isn't goofed up somehow.
If none of that helps, I may have to just move on to the ignition system. Perhaps the condenser is causing weak spark once it's warmed up? Coil going bad?
At this point, all I can do is just make a list of things to try, and then start marking them off one by one as I do them. At some point, I'll find the issue. Hopefully I find it sometime this year though haha!
Here's a quick video I made earlier today when I did another pressure test to check the new seal I installed:
