Microlighters

On the left, a BC 31 GUD filter cut open, after 188 hours! The dark stain on the bottom in where it caught water and HELD IT there. Filter still very faaaar from unservisable, but the hours used was just to prove my point. Now you try THIS with the little piece on the right!!

Wow .... point taken.
That little one on the right is is still bigger and of a better quality than some I have seen and used.

What is the height of the GUD Filter?
It may be a bit big for the trikes...... or is it?

bobthebuilder wrote:Wow .... point taken.
That little one on the right is is still bigger and of a better quality than some I have seen and used.

What is the height of the GUD Filter?
It may be a bit big for the trikes...... or is it?

I don't think that the filter on the left can be used with 2 stroke premix, or can it?

The little glass one is a no.. no.. anyway. Had an engine out after 10 hours. Way too small, accident waiting for a place to happen. Go for the bigger GUD in line filter!!

I have fitted the same BC31 type filter in the fuel line before the glass type filter. Reason being those glass type filters can/do jam up but I like to be able to see the fuel flow as well.
Any comments on this arrangement appreciated.

Dont understand completely. To get the glass filter blocked it must be a hell of a lot of dirt or am I wrong. Should it get blocked I will not trust any other filter especially if I cant see the dirt and the paper filter is even more likely to get blocked.

German wrote:Dont understand completely. To get the glass filter blocked it must be a hell of a lot of dirt or am I wrong. Should it get blocked I will not trust any other filter especially if I cant see the dirt and the paper filter is even more likely to get blocked.

The problem with these filters is that the "holes " in the filter element are too small and clog up with very fine particles in the fuel and cause fuel starvation. I had one of these filters on my trike and very nearly lost my motor and my life because of it!
Fuel mixture becomes too lean and this can cause a hole to be burnt in your pistons...engine out .. and you know the rest!

In my opinion... throw them out .... they are bad news !!! Use a standard filter designed for use on trikes and you will never have a problem.

Just my 5c

Later

Rotax specifies that the fuel filter must have a mesh size of 0.15 mm and must be fitted between the pump and the carburetor. Paper filters are not suitable for pre-mixed systems and should be avoided. The fuel tank must have a drain cock for condensed water. A screen of 0.3 mm mesh size should be fitted in the fuel line in the tank. Fuel lines must have a minimum diameter of 5 mm.

I use a Mercedese Benze plastic filter which has a mesh size of 0.15 mm. The newer ones, same part number, are not as transparrent. If you can get the older ones they are easier to inspect for dirt. From time to time, when I see dirt in the filter, I reverse flush it to get rid of the dirt. My filler syphoning pipe also has a 0.3 mm mesh filter on the end and I have regularly found dirt in it. After 150 hrs I replace my fuel filter this morning. There were granules of brown dirt and things that looked like hair in it.

Clean fuel and properly filtered fuel is a must to prevent engine trouble.

My 2C worth.

Chucked my glass filters out many moons ago.

Mulderpm i would recommend that you change your filter every 25 hrs. The consequence of a blocked filter is so huge and the cost of filters are so low that it just makes good sense to change more often

Point taken Thatchman.

The glass one is a no no. They leak and you will suck air in. They either vibrate loose, or the rubber washer gets eaten by the fuel and perishes. Had a number of trikes that had them fitted, and there was about a 90% failure rate. At the time when we researched it - it came out that they were meant for gas installations and not fuel hence the perishing rubber.

Toss them.

There was once (maybe still) a paper element filter for the Mercedes 300 Diesel, made by GUD. This was/is an inline filter, and should be perfectly good to use with pre-mix fuel , as diesel is a lot more viscous than pre-mix petrol
Jean.

Thatchman wrote:Chucked my glass filters out many moons ago.

Mulderpm i would recommend that you change your filter every 25 hrs. The consequence of a blocked filter is so huge and the cost of filters are so low that it just makes good sense to change more often

100% Thatchman!!

I really don't understand why you would want to experiment with such a critical piece of equipment!

The rule is simple: Use the stock standard translucent plastic filter and replace every 25 hours!

Inspect the filter for water or dirt build-up with EVERY pre-flight.

Simple. Easy. Inexpensive. And it works!!

Safe Skies!

John.com

Bla Bla Bla Bla
I got one of those Mercedes filters on the pipe when I drain fuel from the container to the tank.
I have another one in-line between the tank and the carb.
There is a drain valve at the bottom of the fuel tank and I check for water as a pre-flight item.
I use a clean container.
And I have not had any problems with contaminated fuel the previous 700 hrs.
Have a good flight.!

That stupid little pice of glass rubbish was nearly the cause of my only engine out ever!!!!, and just 5 hourrs after cleaning. Fortunately, facet saved the day. they are too small.

Paper fuel filters are supposed to be a no-no, purely because paper is supposed to swell when water touches it, never experienced that. ran over 100 hours, no problem. Also don't believe 2-stroke oil will block the filter, that doesn't happen either. All you need to do is filter any large debris from getting to the engine. .3mm mesh is the perfect size. We run these 100 to 200 hours on a 912/4, why should it be different for a 2-stroke?. Ok there are pickup mesh's in the tank that prevents leaves and grass from being picked up.