Fuel Cap Vent

[Highlander1959]

I have an old Craftsman 2.0 (same as Poulan Micro or 2300). I know these saws are basically toys but it serves my needs for a small, lightweight saw. My question is, is there a newer VENTED gas cap available for these saws or some sort of vent I can install in the cap? It seems the only provision the manufacturer made for venting the fuel tank is the leakage around the point where the fuel line enters the tank. There is no vent in the gas cap and, after replacing the fuel lines recently, I've found that it's very hard to get the saw primed and keep it running properly. Loosening the cap solves the problem but then it leaks fuel. Great design, huh? But I suppose that's what you get with a cheap tool. Anyway, if anyone has encountered this issue or has any ideas for a fix, I'd appreciate hearing from you. Cheers ...

 

[J D]

I believe I had a similar problem with mine & managed to find a cap that fit of a random string trimmer... can't remember what it was sorry

 

[RedneckChainsawRepair]

Also if you dont have the newer cap like he shows above. They can still be bought cheap new.
IMO they are better then the early flat caps.

 

[Highlander1959]

I believe I had a similar problem with mine & managed to find a cap that fit of a random string trimmer... can't remember what it was sorry
View attachment 1047130View attachment 1047131

That's exactly what I suspected. I'll dig around and see if I have something like that...

 

[Highlander1959]

Also if you dont have the newer cap like he shows above. They can still be bought cheap new.
IMO they are better then the early flat caps.

View attachment 1047147View attachment 1047149

That helps. If I can't find something in my junk pile, I should be able to get one of those.

 

[Highlander1959]

That's exactly what I suspected. I'll dig around and see if I have something like that...

I'm exploring the option of putting a primer bulb on it too since, from what I've been reading here and elsewhere, these saws are notoriously hard to start once the fuel line is empty. I think there's room to put one on the air cleaner cover.

 

[J D]

I'm exploring the option of putting a primer bulb on it too since, from what I've been reading here and elsewhere, these saws are notoriously hard to start once the fuel line is empty. I think there's room to put one on the air cleaner cover.

I think it would be considerably more trouble than it's worth.
My start procedure is choke on, drop start holding WOT until "pop", choke off, drop start holding WOT until fires (then dies), choke back on, drop start holding WOT until "pops" (again), choke off, drop start holding WOT & will fire & run

 

[Old2stroke]

I'm exploring the option of putting a primer bulb on it too since, from what I've been reading here and elsewhere, these saws are notoriously hard to start once the fuel line is empty. I think there's room to put one on the air cleaner cover.

Hard to do, a "primer" installation is really a purge system and requires a connection directly to the fuel chamber of the carb so that it can suck fuel up the line, through the fuel pump and inlet valve to remove any air and fill the carbs' fuel chamber with fuel. If you carb doesn't have that extra port it will be difficult (not impossible) to add it.

 

[a. palmer jr.]

If you run it completely out of fuel you can always put a dab in the spark plug hole or at the air filter. That might run it long enough to get fuel pumped to the carb. No need to wear out the starter..

 

[Highlander1959]

If you run it completely out of fuel you can always put a dab in the spark plug hole or at the air filter. That might run it long enough to get fuel pumped to the carb. No need to wear out the starter..

I've done that plenty of times but i have a low tolerance for power tools that require disassembly to start them

 

[Highlander1959]

Hard to do, a "primer" installation is really a purge system and requires a connection directly to the fuel chamber of the carb so that it can suck fuel up the line, through the fuel pump and inlet valve to remove any air and fill the carbs' fuel chamber with fuel. If you carb doesn't have that extra port it will be difficult (not impossible) to add it.

Yeah, I certainly plan to explore all other options before trying anything like that. I'm pretty sure switching to a vented gas cap will solve my problem. If not, I'll be performing a thorough vacuum check on the crankcase and fixing any vacuum leaks. That SHOULD restore it to usable condition. I already rebuilt the carb and replaced all the gaskets since I had it apart and keep plenty of Walbro kits on hand.

It was starting pretty easily until I replaced the fuel line but I used fuel line that fit very snugly and it never occurred to me that there was no vent in the tank. I also discovered that the larger fuel line can be pinched quite easily in the handle if you don't route it just right. I was tearing my hair out trying to get it to suck fuel after my "quick repair". Eventually I put a vacuum pump on the line, only to find that no amount of vacuum was going to draw fuel up the line. I found where it was pinched and I thought I had finally fixed it when it fired right up, only to discover that it STILL had fuel delivery problems due to the lack of a tank vent. It's no wonder so much lawn and garden equipment winds up in the trash. You can spend hours trying to fix these things sometimes, especially when multiple issues are involved and you start chasing your tail

 

[cookies]

I've done that plenty of times but i have a low tolerance for power tools that require disassembly to start them

Then Don't run it out of fuel LOL , its 40 years old and might be time for some rings to increase vacuum/compression to make starting faster/easier/less pulls. Could also have a hard/warped fuel pump diaphragm supplying less fuel at start up.

 

[Highlander1959]

Then Don't run it out of fuel LOL , its 40 years old and might be time for some rings to increase vacuum/compression to make starting faster/easier/less pulls. Could also have a hard/warped fuel pump diaphragm supplying less fuel at start up.

Sure, it's old but so am I and my frugal German nature prevents me from giving up on anything that still has life in it. This saw has gotten plenty of maintenance over the years ... including regular carb rebuilds, but my tendency to overdo things got the better of me this time. Using the slightly larger fuel line that fit too tightly wound up causing an unexpected problem. I'd never even noticed that the fuel tank had no actual vent in it. I'd rather put a vented cap on it though, as opposed to dealing with the persistent fuel line leaks common with these cheap small engines as the fuel line ages and shrinks. The compression on this saw is good and the piston, while not perfect, looks OK. If I do a vacuum test and find significant vacuum leaks, then I'll probably wind up doing the crank seals, at which point the cylinder and piston might get some work too. I've already ordered the seals. Whatever it takes ... this issue with the fuel line really had me stumped though. I had a similar "tear my hair out" moment a while back with another small saw that was working perfectly until one day when it just wouldn't start. They always say "compression, fuel, spark" right? I checked everything I could think of but the damn thing just wouldn't start. I finally gave up on it in favor of more important tasks but one day as it was lying on the bench begging for my attention I glanced over at it and noticed something strange. The exhaust port was brown, not black. A mud dauber wasp had built a nest in the exhaust port. I cleared that out and it ran like new on the first pull. Now, I've amended my troubleshooting process ... it's " compression, fuel, spark, and EXHAUST" ... live and learn.

 

[cookies]

Sure, it's old but so am I and my frugal German nature prevents me from giving up on anything that still has life in it. This saw has gotten plenty of maintenance over the years ... including regular carb rebuilds, but my tendency to overdo things got the better of me this time. Using the slightly larger fuel line that fit too tightly wound up causing an unexpected problem. I'd never even noticed that the fuel tank had no actual vent in it. I'd rather put a vented cap on it though, as opposed to dealing with the persistent fuel line leaks common with these cheap small engines as the fuel line ages and shrinks. The compression on this saw is good and the piston, while not perfect, looks OK. If I do a vacuum test and find significant vacuum leaks, then I'll probably wind up doing the crank seals, at which point the cylinder and piston might get some work too. I've already ordered the seals. Whatever it takes ... this issue with the fuel line really had me stumped though. I had a similar "tear my hair out" moment a while back with another small saw that was working perfectly until one day when it just wouldn't start. They always say "compression, fuel, spark" right? I checked everything I could think of but the damn thing just wouldn't start. I finally gave up on it in favor of more important tasks but one day as it was lying on the bench begging for my attention I glanced over at it and noticed something strange. The exhaust port was brown, not black. A mud dauber wasp had built a nest in the exhaust port. I cleared that out and it ran like new on the first pull. Now, I've amended my troubleshooting process ... it's " compression, fuel, spark, and EXHAUST" ... live and learn.

I started installing the black echo/stihl fuel hoses on saws that formerly used tygon-- they will last 10+ years
I hate tygon because it lasts 2 years or less before it hardens, shrinks, cracks and breaks.
Choke plate and impulse are what I check if compression is over 140 and has new carb guts and still hard to start.

 

[Old2stroke]

When starting a saw with empty fuel lines and empty carb, it's all about how affective the choke is, must be fully closed and even helps to solder the air bleed hole in the plate closed. At cranking speed the fuel pump has little affect on bringing fuel into the carb. Also the fuel chamber diaphragm must be flexible enough so that the vacuum will pull it down and open the inlet valve or no fuel will get pulled in, (control lever set right). Must be no air leaks in the fuel intake path and throttle should be partially open so that vacuum is exposed to the main jet which will help the vacuum get to the fuel chamber.

 

[Okie]

I've got some of them saws and I use the type fuel caps that have the replaceable Homie duckbill as a vent
AND
no problem with getting a cold start on mine, just dump spoonfull of gas into the muffler if it needs a fast prime.

Installing a primer bulb is not an option because the carb is WRONG type for a primer bulb.

Maybe you need to do like Brandon suggests and get a battery operated saw.

 

[Highlander1959]

I've got some of them saws and I use the type fuel caps that have the replaceable Homie duckbill as a vent
AND
no problem with getting a cold start on mine, just dump spoonfull of gas into the muffler if it needs a fast prime.

Installing a primer bulb is not an option because the carb is WRONG type for a primer bulb.

Maybe you need to do like Brandon suggests and get a battery operated saw.

Understood about the wrong carb type but I'm an engineer. If need be, I'm sure I can figure out a way to squirt a shot of fuel into the carb throat without taking the thing apart or getting tools out every time I want to use it. However, I intend to do what I can to get it fixed properly before I resort to that though. I do own a battery powered pole saw and I bought my wife a small battery powered saw to spare her the noise and hassle of a gas powered saw. She uses it to clear branches and small dead fall on the trails in our woods. Battery powered tools definitely have their place but just between you and me, Brandon can kiss my asp.

 

[Highlander1959]

I started installing the black echo/stihl fuel hoses on saws that formerly used tygon-- they will last 10+ years
I hate tygon because it lasts 2 years or less before it hardens, shrinks, cracks and breaks.
Choke plate and impulse are what I check if compression is over 140 and has new carb guts and still hard to start.

The most important thing is getting ethanol free gas. Thankfully, I have a good source for that here. I mix my own fuel and the problems I used to have with vapor lock and ethanol damage are history. I don't even use that ridiculous pre-mix fuel. Too expensive and questionable quality...

 

[Highlander1959]

When starting a saw with empty fuel lines and empty carb, it's all about how affective the choke is, must be fully closed and even helps to solder the air bleed hole in the plate closed. At cranking speed the fuel pump has little affect on bringing fuel into the carb. Also the fuel chamber diaphragm must be flexible enough so that the vacuum will pull it down and open the inlet valve or no fuel will get pulled in, (control lever set right). Must be no air leaks in the fuel intake path and throttle should be partially open so that vacuum is exposed to the main jet which will help the vacuum get to the fuel chamber.

Yeah, good vacuum is where it's at. Pulling fuel uphill at cranking speeds is a challenge if you have even a tiny leak.

 

[CTH-SXL]

Homelite's way of venting some of their plastic fuel tanks : using their standard #69541 duck bill check valve .
They are readily available on line or thru Oregon .
FYI , the hole in the tank is a snug fit for a #26 drill bit , but a #25 is too large to fit .