Rambling about fuel line/filters

[Sean Bowf]

I have a .45 speedmaster mono that I tried to get to run right last year. It was fast when everything was running right on it, it just did not last very long. Anyhow...I had put together the tanks (16 oz main and a hopper) with the tubing that came with them. I kept getting conflicting recommendations on the tubing (it was fine, it was too small, it was fine for a .45, it was too small for a CMB...etc...etc).

So...I finally gave in and ordered some 5/32 brass tubing, and swapped out the outlet of the main tank, and the inlet to the hopper with the larger tubing. I was curious, so I started measuring the ID of the tubing with an inside caliper (the inside end of my digital caliper). I knew that the 5/32 was about an eighth of an inch (.125), so I measured the inside of the 1/8th tubing, and it was about .090. Pretty big difference if you think about the area of it. If my calculations are right, I doubled the area of the tubing by just going up 1/32nd of an inch in diameter.

Anyhow...my point...I am sitting on the floor messing with the tubes, my boat, and my caliper...and I looked at my filter...and realized how small the hole in it looked. So...I put the caliper on it, and its ID was .080. Well...fooey. If you think about it, just switching out the filter would have got me 28% more area (compared to the inside of the eighth inch tube)... I still have to wonder about the tubing and the filter...and if it was causing my problem, because it seems that the needle would flow less fuel than ANYTHING in my fuel system...

I drilled the filter out to .109, but I know that is still less than the inside of my new tank tubing...anyone got a link to a filter that has large enough flow for my purpose?

Sorry about the long ramble...

Thanks,

Sean

 

[Dr Hydro]

Don't forget to measure the nipple on the carb. I agree with you. The fuel will only flow as fast as the smallest hole will let it.

 

[dwilfong]

Ok so how big should the holes on every thing be to run a .45?

Setting up the fuel system on my new boat right now.

On the old boat seams that I could never get the needle fat.

 

[shoboat]

Sean,

Lose the filter period, just keep your fuel clean.

My Two Cents,

Mark Sholund

 

[shawdaddy]

Sean,
Lose the filter period, just keep your fuel clean.

My Two Cents,

Mark Sholund

I agree with Mark. I have never run a filter on any of my boats but I do have a filter on my fuel can. Ryon Shaw

 

[glenng]

I have a .45 speedmaster mono that I tried to get to run right last year. It was fast when everything was running right on it, it just did not last very long. Anyhow...I had put together the tanks (16 oz main and a hopper) with the tubing that came with them. I kept getting conflicting recommendations on the tubing (it was fine, it was too small, it was fine for a .45, it was too small for a CMB...etc...etc).
So...I finally gave in and ordered some 5/32 brass tubing, and swapped out the outlet of the main tank, and the inlet to the hopper with the larger tubing. I was curious, so I started measuring the ID of the tubing with an inside caliper (the inside end of my digital caliper). I knew that the 5/32 was about an eighth of an inch (.125), so I measured the inside of the 1/8th tubing, and it was about .090. Pretty big difference if you think about the area of it. If my calculations are right, I doubled the area of the tubing by just going up 1/32nd of an inch in diameter.

Anyhow...my point...I am sitting on the floor messing with the tubes, my boat, and my caliper...and I looked at my filter...and realized how small the hole in it looked. So...I put the caliper on it, and its ID was .080. Well...fooey. If you think about it, must switching out the filter would have got me 28% more area (compared to the inside of the eighth inch tube)... I still have to wonder about the tubing and the filter...and if it was causing my problem, because it seems that the needle would flow less fuel than ANYTHING in my fuel system...

I drilled the filter out to .109, but I know that is still less than the inside of my new tank tubing...anyone got a link to a filter that has large enough flow for my purpose?

Sorry about the long ramble...

Thanks,

Sean

Sean , I put up a post about using a three tank setup about a month ago and learned it's not about the size of the line going from the hopper to the filter/carb. I was told to use the larger lines/preassure fittings from the pipe preassure to the vent side of the tanks to move fuel more efficiently from one tank to the next. If you check the inside diameter of the fuel nipple on the carb-you may be supprised- I checked the I.D. of the fuel inlet on the O.S. 9B carbs on my .67/.80 motors and it was .064"!!!!!

Best of luck, Glenn

 

[M@MRacing]

Put the filter in the gallon of fuel and filter it that way

 

[Joe Warren]

I have a .45 speedmaster mono that I tried to get to run right last year. It was fast when everything was running right on it, it just did not last very long. Anyhow...I had put together the tanks (16 oz main and a hopper) with the tubing that came with them. I kept getting conflicting recommendations on the tubing (it was fine, it was too small, it was fine for a .45, it was too small for a CMB...etc...etc).
So...I finally gave in and ordered some 5/32 brass tubing, and swapped out the outlet of the main tank, and the inlet to the hopper with the larger tubing. I was curious, so I started measuring the ID of the tubing with an inside caliper (the inside end of my digital caliper). I knew that the 5/32 was about an eighth of an inch (.125), so I measured the inside of the 1/8th tubing, and it was about .090. Pretty big difference if you think about the area of it. If my calculations are right, I doubled the area of the tubing by just going up 1/32nd of an inch in diameter.

Anyhow...my point...I am sitting on the floor messing with the tubes, my boat, and my caliper...and I looked at my filter...and realized how small the hole in it looked. So...I put the caliper on it, and its ID was .080. Well...fooey. If you think about it, just switching out the filter would have got me 28% more area (compared to the inside of the eighth inch tube)... I still have to wonder about the tubing and the filter...and if it was causing my problem, because it seems that the needle would flow less fuel than ANYTHING in my fuel system...

I drilled the filter out to .109, but I know that is still less than the inside of my new tank tubing...anyone got a link to a filter that has large enough flow for my purpose?

Sorry about the long ramble...

Thanks,

Sean

If you must run a filter run a Dubro LARGE Filter. if you neglect it & the trash stops the screen up on the Filter. It becomes the primary needle & the 3rd channel becomes the secondary needle. Also double check you pipe pressure fitting to make sure it is Clear. Especially if it is a 90 degree Pipe Fitting. I run 1/8 tubing in everything unless it is a 90 (15cc) then I go to 5/32.

 

[Michael Costanzo]

HI SEAN, I ALWAYS TRY TO RUN A FILTER(IF NOT IN THE BOAT ,TRY TO FILTER IT ON FUEL JUG SIDE). I HAVE ALWAYS RUN MEDIUM SIZE FUEL TUBING AND SAME SIZE FUEL FILTER. GO TO TOWER HOBBIES PAGE AND PICK A FILTER AND THATS IT. MIKE. PS, SORRY FOR CAPS,KEY STUCK.

 

[John Knight]

Sean,
Lose the filter period, just keep your fuel clean.

My Two Cents,

Mark Sholund

I agree with a twist. I have a ceramic filter in the fuel bottle and a filter in the line going to the pump. Then 2 filters in the line from the pump to the tank. Total is 4 filters. I never have any junk going into the tank. Then flush the tank after running with WD-40 to keep them clean. Flush out the fuel line from the tank through the 3rd needle - BOTH ways - to the carb. Then your system stays clean without any junk and the fuel stays pure. Overkill - nah, as it stays always clean, and the pump too.

 

[glenng]

Sean,
Lose the filter period, just keep your fuel clean.

My Two Cents,

Mark Sholund

I agree with a twist. I have a ceramic filter in the fuel bottle and a filter in the line going to the pump. Then 2 filters in the line from the pump to the tank. Total is 4 filters. I never have any junk going into the tank. Then flush the tank after running with WD-40 to keep them clean. Flush out the fuel line from the tank through the 3rd needle - BOTH ways - to the carb. Then your system stays clean without any junk and the fuel stays pure. Overkill - nah, as it stays always clean, and the pump too.

You might also take the remote needle apart to look for debris. I bought three B.V. needles about a year ago(used) took them apart recently and found debris in all three.Glenn

 

[Tom Foley]

BTW 5/32 is .156250 ..not .125000 . I always run two filters on the jug one going to each carb , blast with brakekleen both sides each fill and visually look through the filter . do what you want but from time to time there is trash in the filter , especially if you run metal tanks and don't run that much . In over 5 years my needles have never changed on my twin but a click one way or the other for conditions . Here is the bottom line ..if you run filters ..you have to check them all the time .

 

[Rigged]

I also try not to run filters in my fuel system in the boats as that can just cause for another aggrivating air leak sometimes. I guess im kinda anal about not wanting any junk in the system in my boat, so i run a filtered clunk in my fuel jug, another filter (standard dubro) before the hand crank pump, and then another filter after the pump (that makes for a total of 5 filters counting the 2 in the carb to keep anything from getting into the motor). While some boats i do still run a filter in them, even with the Large dubro filters, i still drill out both ends with a 1/8 bit (of course, this is for a gasser).

 

[Charles Perdue]

Some of the top boaters rinse their fuel jugs with methanol, blow them dry and filter the fuel and any extra components, through coffee filters, sometimes doubled up. Catches any "nitro lint" before the fuel system.

If you do use an inline filter, make sure that it is before the 3rd channel needle.

Charles

 

[Don Ferrette]

To each his own but I run in line filters in every boat and would not run any other way. I also filter the fuel out of the jug and with that being said I only run the larger Dubro in line filters that you can take apart and clean if needed. They have a large screen area so the the chances of a total shut down of flow from debris is virtually non existent as long as you check them periodically and will easily flow the biggest of motors. All it took was losing one big race because of trash in the needle and I've never run without one since. B)

 

[tmunn]

I run filters on all my boats as well gas and nitro and never had a problem.I also havea filter in my fuel pickup in the gallon jug.

 

[Mark Bullard]

I'm with Don on this one. We have been running the large Dubro filters for years on our fuel systems. We connect them between the tank and needle. On our fuel tanks we run 1/8" tubing on all motors .60 and below and 5/32" on big engines. We also filter the fuel from the jugs. We clean filters before every event and we still find all kinds of things in the filters. But I like it there instead of in the needle.

 

[Sean Bowf]

BTW 5/32 is .156250 ..not .125000 . I always run two filters on the jug one going to each carb , blast with brakekleen both sides each fill and visually look through the filter . do what you want but from time to time there is trash in the filter , especially if you run metal tanks and don't run that much . In over 5 years my needles have never changed on my twin but a click one way or the other for conditions . Here is the bottom line ..if you run filters ..you have to check them all the time .

ID, not OD...the ID is about .125, the OD is .156... I was talking about the ID (inside diameter) because that is where the fuel flows.

Sorry for any confusion.

Sean

 

[Sean Bowf]

OK...for all you guys running filters on your fuel jugs (I do)...here is a question for you...when you are done running for the day, and pump all the fuel out of your boats, back into the jug...which side of the filter is any junk that did make it into your fuel tank on?? It would be on the "boat side" of the filter. This has always bothered me, because the first boat that gets fueled, gets any junk that was on that side of the filter if you forget to pump a little fuel out onto the ground prior to connecting the line to your tanks...

There is probably any easy remedy for this that I am missing...so figured I would throw it out there and see what response I got.

Thanks for all the inputs,

Sean

 

[Rigged]

OK...for all you guys running filters on your fuel jugs (I do)...here is a question for you...when you are done running for the day, and pump all the fuel out of your boats, back into the jug...which side of the filter is any junk that did make it into your fuel tank on?? It would be on the "boat side" of the filter. This has always bothered me, because the first boat that gets fueled, gets any junk that was on that side of the filter if you forget to pump a little fuel out onto the group prior to connecting the line to your tanks...
There is probably any easy remedy for this that I am missing...so figured I would throw it out there and see what response I got.

Thanks for all the inputs,

Sean

Since i run IV Bags for a fuel tank (gas), i do not pump the fuel out of my boats (bags would last about 1 time if left dry) so no worries about that here :lol: