Another pioneer farmsaw with problems

[rupedoggy]

I think madsaw got it. Drain the oil tank and run it. If it clears up then epoxy the divider.

 

[wildcat99s]

I have seen an abnormal amount of oil come out of the muffler and get on my work table. So much is that the other day I tried running a less oil mixture gas and helped for min and then went away. I thought the oil could have been from the excess unburned oil and gas from unsuccessful start attempts. But I will drain it and see if it does anything.

As for the coil right now and last coil has been a homelite coil. I had to slightly modify it but never had any issues before. But I did order a new oem-ish coil I'm waiting to receive.

Right now it's still in pieces but I'm gonna try to put it back together this morning and shoot another video so I can upload them later today when I have the time

 

[wildcat99s]

I'm in the process of uploading some short videos on youtube and i'll post the links when they are finished.

So this morning i drained the oil tank and it didn't make any noticeable difference with it running at the moment. I also took apart the carb and cleaned it again, but this time i removed the little welch plug behind the high needle and found a piece of something stringy... almost like teflon tape, and removed it, and that wasn't the problem. I also took out the check valve and it seems to be working fine. But the brass washer under the check valve is scarred up a little from the check valve being removed a time or two. So tonight i'll take out the brass washer and see if i can clean it up to make sure it's sealing.... which is something i haven't did yet.

Another question about the check valve. does the threads need to be sealed for the check valve. Originally there was loctite or something on the threads... which i though was just keeping it from backing out. But does those threads need to be sealed? like with teflon tape or loctite?

Another thing i'm going to check is the metering lever. I was looking at the manual and think i may have messed up the lever by bending it incorrectly and may have bent with the small fork that holds the needle itself by accident. I'm only saying that because i remember it angling down a little bit, and the manual shows it parallel with the chamber floor, along with the lever being flush with the floor. I have a couple new ones so i'll swap it out and reset it tonight.

Another observation i've made. Even tho it's running like crap, and half of the time won't run at all. I can tell that the adjustment screws for the carb are working. On the LOW side, the saw will attempt, and sometimes start as long as the screw is between 1 to 1 3/4 out. Which the sweet spot is usually around 1 1/4, so that seems to be working. And the HIGH side has activity between 1 and 1 1/2 turns. Anything above or below those limits won't even attempt to start.

At this point i'm grasping at straws. I've checked or replaced virtually every part of the saw, and it's never given me this kind of trouble. Back in the day it was super reliable even though it was worn out. I rebuild it so it should be basically new, and doesn't want to run and it's really frustrating. If it's not the brass washer under the check valve, or the threads on the check valve sucking air causing the issues, i'm running out of ideas.

 

[wildcat99s]

I may be confused on where or what the check valve is. The part i thought was the check valve is actually called the speed limiter. That screws into the side of the body. it looks to act similar to a check valve. The carburetor that's on my saw is a tillotson HS-147D 025.

 

[Old2stroke]

What you have been calling a check valve is a buzz-ball governor and is meant to richen the mixture up at high speeds so much that it won't rev up beyond safe limits and is a common source of over rich problems. It is best to just disable the damn thing either by blocking the port going out to the high speed venturi or the port bringing fuel into it from the fuel cavity of the carb. The actual nozzle check valve will probably be a fine screen under the welch plug covering the high speed jet and the bit you found there may have been a small disc that is part of the check valve. Was there in fact a fine screen under the welch plug on this carb? There are a few variations of the check valve.

 

[wildcat99s]

The first video was this morning after getting it put back together and started for the first time. The low screw was 1 1/4 and high screw was at 1. After it died a couple times i enriched it a time or two at about an 1/8th turn each time. This is average. I can get it to start. sometimes it'll run for a short time. Some time it'll run for a few minutes. And eventually it progresses worse the more i adjust it.



the 2nd video is it running and able to accelerate some, but it's cutting out. this is also average when it runs. sometimes it'll smooth out but a short time, but then goes back to bucking

 

[wildcat99s]

What you have been calling a check valve is a buzz-ball governor and is meant to richen the mixture up at high speeds so much that it won't rev up beyond safe limits and is a common source of over rich problems. It is best to just disable the damn thing either by blocking the port going out to the high speed venturi or the port bringing fuel into it from the fuel cavity of the carb. The actual nozzle check valve will probably be a fine screen under the welch plug covering the high speed jet and the bit you found there may have been a small disc that is part of the check valve. Was there in fact a fine screen under the welch plug on this carb? There are a few variations of the check valve.

Yes, i removed that welch plug the other day and cleaned it and found a little trash in there. There was a fine screen with what looked to be a open jet behind it. I didn't take out the screen but was able to blow through it and thought it was fine so i put it back together. So is that correct? or is there supposed to be some type of check valve under the screen i need to check? like a flap/ ball or something other than an open hole?

 

[Manic84]

From how the saw is running in the videos, it almost does mirror a faulty valve - hard starting, difficulty restarting, going back and forth on the needles, poor acceleration/stalling at WOT. Seems good for a while, then back to it's old crappy self. But the stumble, just to rule out one thing - do you have consistent spark and a intact flywheel key?

With that out of the way, I don't see many Tillotson carbs come in. But it's probably something similar to the Walbro capillary system. I seem to recall that the screen is the "check valve", there should be a ring/clip to keep it in place. If the screen is blocked or damaged in any way, you'll get weird running issues.

Here is some Tillotson literature to help you get a clearer picture and give you some ideas.
The parts list is a better, albeit generic diagram for figuring out your carb.

 

[farmguywithasaw]

Unless you have # 19 that carb has no check valve just a screen. I think maybe the coil you used isn’t happy with the timing

 

[Manic84]

You have a good point. I'm starting to get curious, I wonder if he has the "right" coil? (blue one)
When he said he replaced it, I figured maybe he used another like it originally had. He's ordered up another coil, so we'll see.

(he probably does, but it doesn't hurt to ask.)

 

[Old2stroke]

The fine screen is the check valve, it relies on the surface tension of the fuel to provide enough back resistance. In some carbs, there is also a small black rubber disc under the screen and the HS parts list shows that it is there but parts list can be wrong. Did you disable the governor? From the "run" video it doesn't sound like a mixture problem to me, I vote for erratic ignition.

 

[farmguywithasaw]

The fine screen is the check valve, it relies on the surface tension of the fuel to provide enough back resistance. In some carbs, there is also a small black rubber disc under the screen and the HS parts list shows that it is there but parts list can be wrong. Did you disable the governor? From the "run" video it doesn't sound like a mixture problem to me, I vote for erratic ignition.

It doesn’t show a rubber disc it shows the screen 18, the clip that holds the screen17, and the Welch plug 16. Or 19 which is a nozzle assembly. It will have one or the other

 

[wildcat99s]

So I was able to get my saw working perfectly and wanted to thank everyone for their help. It turns out that it was the coil. This time I bought one of the "blue ones" even tho it isn't blue, and had to modify the bolt holes so it'll line up correctly. I've used another kind of coil for years and never had issues. So it's no telling what was wrong with it. But im happy, even tho I probably put 10 hours into cleaning and repairing every little thing. So it ought to run for another 40 years.

 

[wildcat99s]

So my saw is running like new now.... which is something i'm not used too. before when the saw was cold it usually took me 4-5 pulls before it would start... like full choke for 3-4 pulls until it hits, and go half choke and it would always start in 1-2 pulls. And that was consistent. And then to restart it after it's warm i'd always have to use the trigger lock and it would start in 1-2 pulls and then release the trigger lock to idle down. Now it's starting right up on the 2nd pull when it's cold. And after it runs for more than 30 seconds, it'll start with 1 pull with it being idled down without having to use the throttle lock.

 

[Bret4207]

So my saw is running like new now.... which is something i'm not used too. before when the saw was cold it usually took me 4-5 pulls before it would start... like full choke for 3-4 pulls until it hits, and go half choke and it would always start in 1-2 pulls. And that was consistent. And then to restart it after it's warm i'd always have to use the trigger lock and it would start in 1-2 pulls and then release the trigger lock to idle down. Now it's starting right up on the 2nd pull when it's cold. And after it runs for more than 30 seconds, it'll start with 1 pull with it being idled down without having to use the throttle lock.

I'm late to the party, but which coil were you using that worked? I couldn't find a coil for a Farmsaw for years and passed a few up because they were bad. Love to add one to my collection of runners, so if you could provide an ID on what worked for you I'd appreciate it.

 

[wildcat99s]

I'm late to the party, but which coil were you using that worked? I couldn't find a coil for a Farmsaw for years and passed a few up because they were bad. Love to add one to my collection of runners, so if you could provide an ID on what worked for you I'd appreciate it.

I did a quick search and there are 4 NOS springs listed on ebay for $40 a piece. But i did a lot of digging online and found a cross reference somewhere and i was able to find a different one that worked. It is actually a push mower recoil spring and are currently being sold on amazon for $10, and it worked perfectly and is identical to the stock one. It's listed on amazon as Stens 155-069 Starter Spring, Replaces Lawn-Boy 604257