how much visible fuel in filter

[edbowen]

I have an 06' mini z with Kawasaki motor (52 inch cut)
The machine cut out on me today. I believe it was a fuel problem. I notice that not much flow in fuel filter. (few bubble and some weak flow) When I squeezed the fuel lines (each side after switching shut off to each tank side) I noticed that the fuel seemed to flow faster. My question is how much fuel should you see in the filter and could this be a problem starting with the fuel pump. BTW the unit did restart. This unit is hard to start after using but starts up easily initially after sitting overnight. about 900 hours on the mower. I really do not want to get into adjusting valves if I can avoid. With only 900 hours I think the valves should be ok but seriously wonder about the fuel pump especially with the ethanol mixed fuels. Thanks Ed

 

[edbowen]

model# 927244
Sn#06062019

 

[bertsmobile1]

Fuel filters can be decieving.
The outlet is almost at the inlet end of the paper cone.
So if the filter is pointing outlet up you get an air pocket trapped between the end of the filter and the open end of the outlet .
There is no reason to install them with the correct flow other than the crud will be inside the filter paper & you will not be able to see it.
I regularly fit them upside down, particular on a mower that gets an annual service.

 

[RhettWS]

Fuel filters can be decieving.
The outlet is almost at the inlet end of the paper cone.
So if the filter is pointing outlet up you get an air pocket trapped between the end of the filter and the open end of the outlet .
There is no reason to install them with the correct flow other than the crud will be inside the filter paper & you will not be able to see it.
I regularly fit them upside down, particular on a mower that gets an annual service.

Bert, You always provide some useful help but I'm having a little trouble following you from the way you worded it. I perceive the following.

1. You install the filter backwards (flow is in the opposite direction of the little arrows).
2. Installing the filter backwards makes the trash less visible.
3. I can't figure out how swapping the thing around will avoid the air bubble, if indeed that is the problem. Maybe it is easier to see the bubble and do something about it before you finally hook it up?

Please advise when you get a chance. No rush and thanks again for all your useful help. ......... Rhett

 

[bertsmobile1]

Yes you can not see the trash,
When installed upside down , or back to front if you like the air can not get trapped because the incomming fuel will displace the air out the other end so it flows through the fuel lines and eventually out the carb.

Easy to understand if it is hanging vertical because the outlet will be at the top.
when laying on the side the air pocket will escape as the mower vibrates & bounces around,

 

[577jersey]

Ive see most fuel filter stay low until the float opens up and lets fuel into the bowl,,then after the bowl is full and the float shuts the fuel off by pushing the needle valve up,,the fuel filter doesn’t fill any more.

 

[bertsmobile1]

Ive see most fuel filter stay low until the float opens up and lets fuel into the bowl,,then after the bowl is full and the float shuts the fuel off by pushing the needle valve up,,the fuel filter doesn’t fill any more.

The filter is not 1/2 full. It is completely full all the time.
Some of what is in there is fuel and the rest is air.
None of it can go anywhere unless the outlet is open.
If given the oppertunity the air in the filter will flow up to the highest point.
In the filter, this is the space between the opening in the outlet tube and the top of the filter canister.
When the opening ( float valve ) opens up fuel travels back up the fuel line to the carb till the float cuts off the fuel supply
If you used cleat fuel line you would see the tube from the filter to the carb is totally full of fuel it is just a pocket of air that gets trapped in the filter.
The only downside is you are only using part of the filter media if you have a big air bubble.

Usually the air works it's way out by breaking up into smaller bubbles and getting sucked up into the carb where it is vented by the bowl vent.
If it worries you put it on backwards and hold it so the outlet side is up and the air will escape
or fit it right way round , hold it inlet side up to allow the air to escape up the tube to the pump then remover the fuel line at the pump , fill it with fuel then replace the fuel line while cranking the engine.
Very messy and you will still have an air pocket but it will be at the outlet end of the fuel pump and eventually get dragged down to the fuel filter.
Or you could buy a really expensive filter with a water trap & air purge valve.

 

[edbowen]

The reason I posted this was really because the motor would stumble like it was not getting enough fuel while at idle. I replace the fuel pump and looks like problem corrected itself. Still only small amount of visible fuel in filter after running but full after sitting for a while.
I have another question. The fuel pump, is this just something to assist the gravity feed in these motors? Thanks Ed

 

[577jersey]

The reason I posted this was really because the motor would stumble like it was not getting enough fuel while at idle. I replace the fuel pump and looks like problem corrected itself. Still only small amount of visible fuel in filter after running but full after sitting for a while.
I have another question. The fuel pump, is this just something to assist the gravity feed in these motors? Thanks Ed

I think its pretty much a vacuum ran pump,,not sure how strong it is,,I was planning on getting a 12v electric pump for mine someday,,i know they will pump fuel 10ft up hill no problem,,not too sure how strong the vacuum pumps are though....

 

[bertsmobile1]

An impulse pump should lift fuel about 2 to 3 feet.
The carburettor is calibrated to the pump so some times you will get a gravity tank with fuel pump on the engine.
And for the babove reason you can not just fit an electric pump.
Some times it might work but most times the flat does not have sufficient pressure to stop the flow from the pump.
Even fitting gravity carb on an impulse pump engine will oft lead to flooding.