Can't keep my P40 running

[Enginerd]

I think I'm going to give up on this saw and get something a little more modern (like, with anti-vib and a chain brake), but I'm going to make one last attempt at this old pig.
IF I can get it started, I can usually cut through one tank of gas (provided I don't stall it). After the first tank, it wont re-start. I see air bubbles in the fuel line. If I remove the line, turn the saw on its side, and let gas pour out, sometimes I can get the bubbles out, but it still wont start. Once it cools off, it might start, but it takes a lot of work. By the time I get it started, I'm so exhausted (read "out of shape") that I don't feel much like cutting anything. Some days I have resorted to putting my half inch drill on the flywheel and using it as an electric start. It can still take me 5 minutes to get her running (and once I even killed a cheap drill).
I recently saw a thread that reccommends a 32:1 mix for these old saws. On the side of the case in permanent marker it says 16:1. Am I over oiling it and making it foul plugs? I've tried adjusting the carb, but that doesn't seem to help.
Any thoughts?

(2171, here I come)

 

[cord arrow]

Some days I have resorted to putting my half inch drill on the flywheel and using it as an electric start. It can still take me 5 minutes to get her running (and once I even killed a cheap drill).

.....i believe you've answered your own question. this "old pig" is dead. has been dead. will remain dead. i'm afraid to ask what it is. don't want to know.

.....yeah, something with a chain brake<font color=red> COULD POSSIBLY </font>bring you in to the current century.

.....that being said, i do run a couple of old husky 65's. they're in great shape, strong old saws, i keep 'em up real tight. i don't, however, ask them to buck all day. i love the old school torque of these dudes. just the exhaust note gets my blood boilin'.............

 

[TimberPig]

It sounds like you could have multiple issues that are causing the problems. Start with compression. If it is low, due to a worn out or scored piston and cylinder, then without fixing that, nothing you do will help it. You may also have spark and fuel system issues, particularly since you are getting air into your fuel system. If the compression is ok, a carb kit, fuel line and filter, impulse line (if used, some use a port in the carb flange instead) and checking to ensure there are no seal and gasket leaks could go a long way to getting it running.

That said, something newer will be much nicer to run, and you could still fix this one up for a backup and a project if you chose to do so.

 

[BlueRidgeMark]

Wow! You can start one of these with an electric drill? That's impressive!

 

[donnyman]

Hellow.If you check the copresson remove th starter as when you pull the starter rope you will activate the decoperssor value.You are better to pull the muffler and take a look.If the piston has melted and pulled over the ring thats your problem.If not I check the gas filter and gas line as it may have a tear or hole in it.Maybe just change it .Is simple.You can also take the top off the carb and check to see if you have lost a pair of wool socks in the screen.Also does that saw have points or electronic ignition.Electric will be blue coloured coil,points will have black coil.Alsop carb ajustments should be set at hi speed 11/2 low speed 11/4 then adjust your idel speed.Hope this helps.Don.

 

[Enginerd]

Thanks!

Thanks for all the replies.

Start with compression. If it is low, due to a worn out or scored piston and cylinder, then without fixing that, nothing you do will help it.

My dad has owned the saw since it was new, and he maintains things pretty well. He also had it serviced maybe 20 hours (10 years) ago from the dealer he bought it from in the 70's(got a new gas tank & a tune up). I like to think if it had bad compression, he would have said something. But then again, that guy is a little different than most.

If the compression is ok, a carb kit, fuel line and filter, impulse line (if used, some use a port in the carb flange instead) and checking to ensure there are no seal and gasket leaks could go a long way to getting it running.

I put in a carb kit about 5 hours ago. It ran nice for about 3 hours, then back to its old tricks. Any chance the 16:1 mix is gumming things up?

That said, something newer will be much nicer to run, and you could still fix this one up for a backup and a project if you chose to do so.

Agreed.

remove the starter as when you pull the starter rope you will activate the decoperssor valve.

HA! Decompressor Valve! You're killing me! That's why I use a drill... 45 or 50 pulls on this thing and I need to go lay down...

Also carb ajustments should be set at hi speed 11/2 low speed 11/4 then adjust your idel speed.

This is great info. I was always kind of guessing where to start. BTW, I don't have a lot of faith in the springs that are supposed to put tension on the needle valves to keep them from unthreading over time. Should I try some removable thread locker if I find the right setting?

I am always torn between fixing old stuff, and buying new stuff. The new stuff is always better, but it's a waste to junk something that might be salvageable just because I’m too lazy to spend time fixing it. I'm very bipolar this way. I have a brand new minivan, but I'd rather drive my 26 year old Scout to work. I'd love a new riding tractor, but my 64 Bolens Husky is still hanging on by a thread, so I continue to use it.

The more I think about fixing this saw, the more I think a shiny new Jonsered 2171 would start easier, weigh less, cut more, and be less likely to remove my arm if it kicked back. If I can get the P40 running, I think I’ll use it as a backup. If nothing else, it sure does sound cool.

 

[TimberPig]

You've got nothing to lose by trying a mix with less oil in it. Try 32:1 and see if it helps.

The springs are fine. Leave them alone and don't even think about using loctite on those screws unless you want more headaches.

Just because it has been owned since new, well maintained, serviced recently, doesn't mean you won't have any issues. You need to check these things to eliminate them as possibilities. Not doing so, may cause the problem to be overlooked, leaving you incredibly frustrated simply because you wouldn't check it to make sure. It is part of good systematic troubleshooting to check things like compression and spark, to ensure that it isn't the cause, before you move on to other possible causes.

 

[Enginerd]

You need to check these things to eliminate them as possibilities. Not doing so, may cause the problem to be overlooked, leaving you incredibly frustrated simply because you wouldn't check it to make sure.

Good point. Any idea what good compression is on a 30 year old 4ci saw?

 

[TimberPig]

If its less than 110 lbs, there's going to be major issues, below 120 lbs, things start going downhill, if you've got 130 lbs or more, it should run fine on that, provided the crankcase is still well sealed, ie no crank seal leaks.

 

[woodfarmer]

2171

go for the 2171 and never look back, it is probably the best all around saw made. i too have worn out my shoulder on an old pioneer.

 

[lesorubcheek]

I love my P40. Lots of torque and an awesome design. Sorry to hear about your difficulties.

Air in the gas line sounds like a possible crack in the line, but if the saw runs through a complete tank and is running normally, I'm not sure this is case. If you're running the saw until the tank is empty, then naturally you're going to suck in air, but after refueling, the air should pass through after a few pulls if the diaphragm is pumping normally.

Have you checked the plug? 16:1 is alot of oil. I usually run either 32:1 or 40:1 depending upon the brand of oil. You may be simply gumming up the plug. Tons of debate on this site regarding oil mixture ratios that you can search.

The P40,50,60s from Pioneer have many good characteristics. Their anti-vibe design does work and they have good balance. If you decide to get rid of it, you shouldn't have difficulty finding a buyer. Hopefully you can find the problem and keep it going.

Good luck,
Dan

 

[Gologit]

Enginerd...Just go out and buy yourself a new saw You know you want to. Drive to saw shop,reach into back pocket,grasp wallet firmly and remove. Extract cash or credit card,sign reciept,go home grinning.

 

[Enginerd]

go for the 2171 and never look back, it is probably the best all around saw made. i too have worn out my shoulder on an old pioneer.

Yeah, I'm thinking that too. I picked up a Poulan 3314 at HD for less than a C-note last week. I'll use that for limbing and get a 2171 with a 28" bar for felling/bucking.

BTW, do you have a wrap handle? I am debating about wrap or flush. I'd like to know if the wrap handle is simply an additional handle mounted to the right side of the body, or is it a whole different handle from the flush design? If I can remove the portion on the right side of the body for a flush cut, then I'll get it. Otherwise, I think I'll skip it.

If you decide to get rid of it, you shouldn't have difficulty finding a buyer.

They seem to go for decent money on ebay. If I can get it running with only a couple hours work, great. If not, it will be listed in the trading post or on ebay. The 30" OEM bar and the 20" Oregon Powermatch Plus should be worth something, even if the saw is for parts.

 

[Jim Mesthene]

I bought my P40 new in 1975. Always has been a hard starter. I use starting fluid. I've been using starting fluid for 15 years, I'm still waiting for it to kill my motor. After it fires once, it's fine. Have you checked your fuel tank vent? That would cause your bubbles in the fuel line and hard hot start. It's a great saw to use; light, balanced and torquey.
But I am 31 years older too. I bought a Husky 350, thinking I could run the old saw if I needed more power. I love the light weight, easy start and safety features. It's almost as fast as my P40 so long as I keep the chain razor sharp. It's way easier on my back.
I say you should give in to your urge for new equipment but fix the old one too. I did and am very happy about my choice.

 

[TimberPig]

BTW, do you have a wrap handle? I am debating about wrap or flush. I'd like to know if the wrap handle is simply an additional handle mounted to the right side of the body, or is it a whole different handle from the flush design? If I can remove the portion on the right side of the body for a flush cut, then I'll get it. Otherwise, I think I'll skip it.

The right side where the handle wraps down over the sprocket cover is welded to the rest of the bar, and cannot be removed. It is a completely separate handle from the flushcut design, in that it has the wraparound portion that goes down over the sprocket cover and mounts underneath.

This means little if you are buying a 2171 Jonsered anyhow, as they do not have a factory wrap handle option. The only Jonsered saw that has a wrap handle available factory that I know of, is the 2186. I'm not sure if a wrap handle off a 372 could be mounted on a 2171 or not.

 

[Enginerd]

This means little if you are buying a 2171 Jonsered anyhow, as they do not have a factory wrap handle option. The only Jonsered saw that has a wrap handle available factory that I know of, is the 2186. I'm not sure if a wrap handle off a 372 could be mounted on a 2171 or not.

I just got a response from a dealer who confirmed what you wrote; the wrap handle is one piece, not two. The 2171 appears to offer the wrap handle stock. Check it out here.

 

[TimberPig]

Jonsered's own website says nothing about the 2171 being available with the wrap handle, only the 2186 is listed as having it available. I think I would check with the company first, before I relied upon a dealer's website, which doesn't correspond with the manufacturer's website on that listing.

 

[Enginerd]

Follow up

Just wanted to thank everyone for their advice and help. I bit the bullet and bought the 2171. I also took the carb apart on the P40 and found the screen was all gummed up. Installed a $5 carb kit, and she fired up on the second pull. I had foolishly ruled out the carb as a problem because it had so little time on it since the last rebuild. Apparently I must have had some gunk in the tank. So in a 3 months time I've gone from having one old cantankerous saw, to 3 saws and no time to drop any trees (remodeling a couple rooms in my house and a 6 month old baby keeps me busy). Every time I swing by my parent’s house, the 50ft pine that blocks the sun from the garden makes me drool. Maybe next weekend...

 

[bump_r]

Don't scoff at the compression relief valve comment. I just took the starter off a P26, and it has a semi-auto valve in there. As you pull the rope, a wire rod is activated that in turn depresses a disc on the valve. The valve is automatically opened as you pull the rope, and closes when tension is released from the rope. I wouldn't be surprised if you have on on your P40...

 

[Enginerd]

Don't scoff at the compression relief valve comment. I just took the starter off a P26, and it has a semi-auto valve in there. As you pull the rope, a wire rod is activated that in turn depresses a disc on the valve. The valve is automatically opened as you pull the rope, and closes when tension is released from the rope. I wouldn't be surprised if you have on on your P40...

No kidding? If it's got one, I'd be surprised if it works. It takes about 3 times the effort to pull the cord on the P40 than the 2171.

I should point out it was donnyman who suggested I remove the top of the carb and "see if you have lost a pair of wool socks in the screen". It appears that was the case. I hate it when a $0.26 part screws up your day. I lost out on a very large load of wood from a neighbor clearing a lot because I couldn't keep the saw running last fall. It all went in the chipper