Villiers 2 stroke question

[Vintage Engine Repairs]

Hi guys, not chainsaw related, but engine related none the less.

It’s an old 1960-1970’s villiers 2 stroke and there is a barb coming off the cylinder intake manifold in front of the carb. I have no idea why it’s there. If I had the manual I’d be able to figure it out, but i can’t see any model or serial on it anywhere.

I have checked and it’s not blocked. The only reasonable answer I can come up with is that it’s a seperate oil feed supplying 2 stroke, but there is no seperate tank...
Any guidance or advice is really appreciated, Thank you!

 

[frank_]

pulse pump ?

 

[Vintage Engine Repairs]

pulse pump ?

View attachment 908591

Hey thanks for the response, Na I don’t think so, there aren’t any diaphragms in the carb, nor barbs on the carb. It runs fine without being attached to anything too.

 

[frank_]

Hey thanks for the response, Na I don’t think so, there aren’t any diaphragms in the carb, nor barbs on the carb. It runs fine without being attached to anything too.

pulse pumps are fitted when the tank is fitted below the carb tom

 

[Vintage Engine Repairs]

pulse pumps are fitted when the tank is fitted below the carb tom

Gotcha, makes sense Frank, thanks for that. This one the tank is above however.

 

[frank_]

whats it fitted to tom ?
some honda mowers use a vacuum operated clutch

 

[Vintage Engine Repairs]

whats it fitted to tom ?
some honda mowers use a vacuum operated clutch

It’s fitted to an edger, here is a video I took of it running. It may help for you to see a quick once around it. Thanks again

 

[mattr66]

Try plugging it. I can't imagine that it is good to have an open vacuum port.

Sent from my motorola edge plus using Tapatalk

 

[Vintage Engine Repairs]

Try plugging it. I can't imagine that it is good to have an open vacuum port.

Sent from my motorola edge plus using Tapatalk

I agree it’s not doing any good. I won’t run it again until I know what it’s for, that short video was just seeing if a carb clean and line repair worked.

Rather than just plugging though it I’d rather know what it does. Before it goes back to its owner, it’s the last thing I need to figure out

It was really kind - I was given it as he said he had always intended on getting it back and running as it was his fathers, but never had the time. He gave it to me knowing I’d take care and appreciate it, however, now it’s fixed I’m going to return it to him. First I need to find out what the hole is for haha.

 

[mattr66]

I agree it’s not doing any good. I won’t run it again until I know what it’s for, that short video was just seeing if a carb clean and line repair worked.

Rather than just plugging though it I’d rather know what it does. Before it goes back to its owner, it’s the last thing I need to figure out

It was really kind - I was given it as he said he had always intended on getting it back and running as it was his fathers, but never had the time. He gave it to me knowing I’d take care and appreciate it, however, now it’s fixed I’m going to return it to him. First I need to find out what the hole is for haha.

It may have went to an accessory like a pump on some configurations but not on this one. It may have had a rubber plug on it that rotted off years ago. If you don't plug it, it will be an air leak that can cause scoring of the piston.

Sent from my motorola edge plus using Tapatalk

 

[Vintage Engine Repairs]

It may have went to an accessory like a pump on some configurations but not on this one. It may have had a rubber plug on it that rotted off years ago. If you don't plug it, it will be an air leak that can cause scoring of the piston.

Sent from my motorola edge plus using Tapatalk

I think this is absolutely plausible mate. There is no function for it on this setup I can see yet it’s there.

 

[ericm979]

On bikes with oil injection that's where the oil feed line goes. Some Villers lawnmower engines had oil injection so maybe some of the motorcycles did too. The pump and tank may be missing now.

 

[Chevboy0167]

Might be a primmer fitting. Old, (ahmmm... I mean vintage), snowmobiles had them. Shoots mixed fuel right into the intake with a black primmer bulb or a plunger setup.

I still use a primmer plunger on my old Kawasaki X2 MOD jet ski. A couple good shots of 110 into the intake ports and off we go!

 

[drf255]

I’d vote it’s for some type of priming mechanism.

Any pump vacuum feed should be fed/located in the crankcase, not the intake port.

 

[Canyon Angler]

Injection port for nitrous oxide and nitromethane? ;-) It'll edge that sidewalk in the low nines!

 

[ray benson]

Can't find a Villiers manual smaller than 98cc. Find any model numbers?

 

[Vintage Engine Repairs]

Can't find a Villiers manual smaller than 98cc. Find any model numbers?

Thanks Ray! It’s now been returned to the owner, I couldn’t find any info on it, but I really appreciate reading the manuals you sent, thank you!

 

[scottr]

Thanks Ray! It’s now been returned to the owner, I couldn’t find any info on it, but I really appreciate reading the manuals you sent, thank you!

 

[scottr]

Thanks Ray! It’s now been returned to the owner, I couldn’t find any info on it, but I really appreciate reading the manuals you sent, thank you!

 

[Vintage Engine Repairs]

Update for everyone - you may recal this post about the barb in the intake, none of us knew what it was for and no manual specified anything about it.

I finally got around to talking to the owner of my Stihl shop, he knew right away.

so that barb should have a hose on it, that hose runs around to the top of the cylinder to an automatic decompression valve.

The vacuum created in the intake manifold at running rpm closes a poppet valve as it acts on a diaphragm held open by a spring. It’s a one way valve so pressure doesn’t affect it.

So, valve stays open while you pull the engine over, then when the engine starts the vacuum closes the valve.


So there we go it’s a barb that transfers negative pressure to an auto decomp!


A video on the function