D
Deleted member 21174
Guest
Why is silicone recommended for the LO206 fuel pump vent? Should the vent be 100% blocked? 50% blocked?
1fasttiller
Member
why would you block the fuel pump vent at all? We run ours as is on all clone motors and even big opens.
Jimbo
You can fool some of the people some of the time
In some cases crankcase pressure can force oil up the hose and then it leaks out the sintered brass filter ALL OVER YOU ENGINE!
Plugging the vent has no ill effects!
Just be sure to clean any oil from the filter with brake clean first.
When ever i do it i always make sure it's the very last thing i do on that engine cause if it isn't there is no doubt that i will lay my hand, arm, shirt or whatever on it before it cures.
Plugging the vent has no ill effects!
Just be sure to clean any oil from the filter with brake clean first.
When ever i do it i always make sure it's the very last thing i do on that engine cause if it isn't there is no doubt that i will lay my hand, arm, shirt or whatever on it before it cures.
SoCo Tire Treatments
Moderator
Lots of the big name builders cover it. Very common.
CarlsonMotorsports
Site Supporter
I think the reason you see it weeping some oil mist from the vent on the 206 is it's mounting location close (and low) to the pulse fitting. Mounting it higher or further away eliminates the problem, (Briggs rules prohibit this somewhat) but it's much simpler to just smear some sealant over it if it leaks enough to bother you.
-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
D
Deleted member 21174
Guest
Why is the vent there at all? Does covering the vent have any impact on fuel delivery (more fuel? less fuel? No impact? )
CarlsonMotorsports
Site Supporter
The volume of the pump/diaphragm is small enough that that it does not require a vent in the capacity that it is made.
No more or less fuel is delivered (GPM) with it sealed or unsealed.
Some similar sized pumps (WIP22/23, WMS, etc) only have a pin-hole in them for air to pulse.
No more or less fuel is delivered (GPM) with it sealed or unsealed.
Some similar sized pumps (WIP22/23, WMS, etc) only have a pin-hole in them for air to pulse.
Jimbo
You can fool some of the people some of the time
I've measured the volume many times to determine if i had a fuel pump problem but i've never measured the pressure.
Therefore, i can't verify this but i contacte Wabro some time ago and the engineer i talked to told me to plug it with silicone to prevent oil leaks. He also said the pump would make more pressure with the vent plugged. FWIW
Therefore, i can't verify this but i contacte Wabro some time ago and the engineer i talked to told me to plug it with silicone to prevent oil leaks. He also said the pump would make more pressure with the vent plugged. FWIW
CarlsonMotorsports
Site Supporter
I don't think this is accurate, Jimbo, at least not from my experience.
If the vent is sealed, the only way the pressure could increase is if the volume of the diaphragm is large enough that it required venting, and subsequent sealing would prevent any leakage past the diaphragm to be captured and thus turned into greater pressure at output.
My experience with these pumps is that if the leakage is that bad past the diaphragm, they simply won't pump enough fuel to the carb for the engine to even run properly.
In reality, we're not looking for "pressure" from this pump as we're not popping off the needle so to speak, simply "filling" the bowl. Yea, yea, there is some pressure needed, I get that, but it's not our primary concern.
For shade tree volume testing of a fuel pump, place the pump to carb fuel line into a gallon container. Use an electric starter to turn the engine at a steady/specific rpm for 1 minute. Kinda crude, but it works.
If you don't have a fuel pressure gauge, you can test fuel delivery simply enough by stretching a tape measure out and measuring how far the fuel squirts at a specific rpm (electric starter.) Simple way to determine if we've got a bad pump on an engine.
I think racers all too quickly point to the fuel pump as their problem, when a simple check is to pull the fuel line at the carb and pull the engine over -- that fuel should "squirt" from the hose, not drip out.
If the vent is sealed, the only way the pressure could increase is if the volume of the diaphragm is large enough that it required venting, and subsequent sealing would prevent any leakage past the diaphragm to be captured and thus turned into greater pressure at output.
My experience with these pumps is that if the leakage is that bad past the diaphragm, they simply won't pump enough fuel to the carb for the engine to even run properly.
In reality, we're not looking for "pressure" from this pump as we're not popping off the needle so to speak, simply "filling" the bowl. Yea, yea, there is some pressure needed, I get that, but it's not our primary concern.
For shade tree volume testing of a fuel pump, place the pump to carb fuel line into a gallon container. Use an electric starter to turn the engine at a steady/specific rpm for 1 minute. Kinda crude, but it works.
If you don't have a fuel pressure gauge, you can test fuel delivery simply enough by stretching a tape measure out and measuring how far the fuel squirts at a specific rpm (electric starter.) Simple way to determine if we've got a bad pump on an engine.
I think racers all too quickly point to the fuel pump as their problem, when a simple check is to pull the fuel line at the carb and pull the engine over -- that fuel should "squirt" from the hose, not drip out.
Jimbo
You can fool some of the people some of the time
Like i said i never verified it but the the engineer i talked to was named Brian also. I don't remember his last name. Actually i met him at Road America later that year. He must have been lying to me. Eh
It doesn't really matter as long as there is sufficient fuel in the float bowl (volume)
The Kiddy Kat snowmobiles and other applications are proof of that. They are gravity feed.
It doesn't really matter as long as there is sufficient fuel in the float bowl (volume)
The Kiddy Kat snowmobiles and other applications are proof of that. They are gravity feed.
CarlsonMotorsports
Site Supporter
Oh, Jimbo, I doubt he was "lying" to you, he just may have a different take on things.
It wouldn't be the first time I've had a disagreement with another engineer.
It wouldn't be the first time I've had a disagreement with another engineer.
Jimbo
You can fool some of the people some of the time
I've been told Briggs plans to come out with a bulletin advising people to be sure to use proper venting of the valve cover and catch can to help prevent building too much pressure in the crankcase.
Some of the aftermarket fittings people use have a very tiny hole in them. Then they use a 1/4" piece of fuel line to connect to a catch can with another tiny hole in it. Some also use a very tiny catch can.
All of these restrictions contribute to building more crankcase pressure which will force oil out the fuel pump breather.
Some of the aftermarket fittings people use have a very tiny hole in them. Then they use a 1/4" piece of fuel line to connect to a catch can with another tiny hole in it. Some also use a very tiny catch can.
All of these restrictions contribute to building more crankcase pressure which will force oil out the fuel pump breather.
CarlsonMotorsports
Site Supporter
1/4" vent line is plenty adequate for the valve cover breather - BUT, the vent/filter size is another issue. The biggest problem I've seen with the catch can filter is that it is not large enough area, or dirty/plugged. The little stone filters plug easily and do not vent a whole lot to begin with. Cleaning your breather filter should be part of your routine maintenance in my opinion.
1fasttiller
Member
Proper crankcase ventilation is crucial on any high RPM race engine. They produce much more CC pressures than normal and that excess needs to go somewhere! I'm wondering if that isn't the cause of so many side cover gaskets and crank seal issues on the clones? I've seen some poor crank case venting and catch cans in my years of karting... it is a non-thought item for most.