394/395 oil tank vent substitution

[Mattyo]

What are spring pins usually used for.
Only ever seen roll pins,but that is here down under.

Seems to me the coiled spring pins are more robust ... but this is my first time really noticing s difference between what I knew to be a roll pin and a spring coil pin. I have roll pins being delivered monday.

 

[Mattyo]

@Moparmyway

Note I'm not the best artist. But the od of then plastic tube seals against the case. The pin just keeps the plastic expanded just enough to be a press fit.

Yes there is a slot for the od of the pin....but that's on the ID of the tube and only limited oil should typically be inside because its constantly under vacuum.

 

[Spladle160]

I pulled one out yesterday. You want it?

 

[Mattyo]

How’s the tube seal against the case gumshoes ? Some mumbojumbodentitemagic ?

If you use a slotted spring pin, it’s going to be leaking when the oil sits on it, whether it’s from a full tank or the saw on the pto side down

View attachment 243352 View attachment 243353

Again....not the best artist

End on view... the blue represents the tube in both cases here. Red is the pins and orange is the case.

Both types of spring pins have gaps. My drawings show the gaps.

 

[Mattyo]

I pulled one out yesterday. You want it?

Thanks! but I'm good at this point. I have one oem for example and still 2 more coming that I've been waiting nearly a month for.

 

[Moparmyway]

@Moparmyway .... the pin expands the plastic tube to press fit seal against the mag case. The od of the tube seals against the case preventing the oil in there from coming out. @qurotro has it right

Maybe there are two different ways Husky did this, however, the ones I’ve replaced have the coiled pin pressed into the case and the tube pushed over the pin



Should you try a roll pin in the picture above, it’s going to leak. I’ve removed roll pins on a few 394’s and installed the OEM coiled pins and have stopped the dreaded oil leakers

 

[Mattyo]

Indeed!!!! Thanks Kevin for the perspective here. The old style was a roll pin with the tube pushed over probably from the back side. The tube didn't seal against the case. The style I'm working on is the newer design. There is an old part number for ...I think both the 262 and 394 and perhaps others. I was wondering how the old style was different an I think you nailed it

 

[Mattyo]

Old part

501839302


See this thread

https://opeforum.com/threads/today-on-this-episode-of-394xp.19394/page-4#post-1012933

 

[BuckthornBonnie]

Again....not the best artist

End on view... the blue represents the tube in both cases here. Red is the pins and orange is the case.

Both types of spring pins have gaps. My drawings show the gaps.

That right there is fridge material for sure. I have some gold stars around if you’d like to grade it haha.

 

[dustinwilt68]

I usually just drill the earlier cases for the newer type vent, I have 10-20 here probably, I always save them on broken cases.

 

[legdelimber]

Heck ain't there a couple of saws that just use a plastic barb~nipple in the hose and you just pull it in through the filler cap? A Poulan model perhaps? Seems like a string trimmer somewhere had that trick also.
I seem to recall something that had a two piece hose with a butt fitting in the middle that just made the tank passage tight.

What about just clipping the barbed section off of a fitting and pushing it into the hose end.
Then you can stuff it in from the top side, if the pathway from the filler cap is obstructed.

I bet the guys that know all the "duck bill" valve crossovers will know what unit has the hose barb trick!

 

[legdelimber]

Here's another thought.
How about cutting the nipple off the back of an old cracked purge bubble and stuff it into the hose?
Takes a few seconds with a fine tooth hacksaw blade to harvest.
Be darned sure and de-burr it with your knife point so that it doesn't shed debris into the oiler pump.
I bet nearly everyone's got one of the little rotted things in the trash somewhere.

 

[Moparmyway]

@Moparmyway
only limited oil should typically be inside because its constantly under vacuum.

It will only be under a slight vacuum when the oil pump is pulling oil from the tank. All other times there is neither negative or positive pressure in the tank. Most people complain that their Husky saw drips oil when it’s sitting around, not when it’s being used

 

[Mattyo]

For the record, I think all of my huskies leak, after they've been drained lol.


That said, the ID of the hose theoretically clears when the oil pump is in use because its under vacuum. Thats its purpose.

During non use time, if positive pressure tends to develop in the oil tank (due to heat differentials, especially in my shed), theoretically the tube end is not in the oil ...because its tucked up inside the top part of the crankcase. Either way, if oil does make inside the tube, and there is positive pressure, its coming out no matter what kind of pin it is.

With the old part number, a roll pin would indeed be more likely to leak because it has a slot which to leak out of ...because that pin "seals" directly to the crankcase, which is different from how the new style works.

With the new style, all the pin has to do is help hold a particular diameter so the plastic tube press fits to the case. On monday when I get the roll pins I'll try one out and see if it splays out the poly tubing enough for a tight press fit.

 

[qurotro]

They will leak anyway... I once tip the 395 starter facing down due to bumpy road and braking. And the whole bed got lubed nicely.

 

[Moparmyway]

Then it came outta the cap, as the vent is on the pto side

 

[Mattyo]

The end of the vent tube is usually on the starter side...jammed to the top of the oil reservoir. So @qurotro describes the exact situation where theoretically you could and should have a leak through the vent tube. This is similar situation to the average spray bottle in your kitchen. Pressure in the bottle forces fluid out the dip tube which is at the bottom of the bottle. When the saw is on its starter side then tube is now at the bottom of the reservoir.

Mine leak even when they are empty though. I hang them in the shed. ..empty and oil still ends up on the floor haha.

 

[Mattyo]

Btw.... @legdelimber ....I just don't know what parts you are taking about ....so in can't respond sorry.

 

[Moparmyway]

Then it came outta the cap, as the vent is on the pto side

The end of the vent tube is usually on the starter side...jammed to the top of the oil reservoir. When the saw is on its starter side then tube is now at the bottom of the reservoir.

That’s true, it could also have been forced up and out through the vent tube

 

[legdelimber]

Btw.... @legdelimber ....I just don't know what parts you are taking about ....so in can't respond sorry.

Mattyo, It's a small hose barb.
I don't know why I'm having such doggone trouble finding an IPL with one properly listed. (maybe I've just gone loony and imagined things?)

The link from Jackssmallengines shows the barb in group 20.
But when you check the price list, it links to the wrong thing (just a, single, strait hose and fuel filter) but not the barb.
Maybe it's simply gone obsolete with the trimmer?
Seem like NAPA ought to have something or maybe someone else has better google skills and can find it online.
Maybe I'm using the wrong name ( hose barb )?

This first link is the engine and fuel tank group for a Ryobi725 trimmer that had the split fuel line and the hose barb.
https://www.jackssmallengines.com/j...25r-41ed725a034-41ed725a034-725r/engine-parts

But yet the second link is what the IPL link take us to.
https://www.jackssmallengines.com/jacks-parts-lookup/part/mtd/791682039
See how it's not the correct item?
Doesn't match what's in the IPL drawing.

I cropped a section of the IPL drawing and red arrowed the hose barb.

Maybe amazon or ebay has something suitable and in a bulk package for cheap!