advice please: replacing fuel system parts...

[bob tilton]

advice please: replacing fuel system parts...

...do i replace everything? here's the situation: new motor but backfires throughout the rpm range. isolated it to the fuel delivery system because it runs fine after i clear the jets but of course starts to backfire again after contamination. initially had problems isolating backfiring due to leaking fuel line (under the car from the tunnel) and leaking exhaust (SSI to pass side muffler). i fixed both of these problems.
i have a good used tank getting boiled/sealed and plan to replace this weekend. the carbs were rebuilt and installed at the same time as the motor. i did not replace the fuel filter when the motor was installed - dumb. the car probably sat long enough in between projects (cv rebuild and motor swap) for the fuel to varnish. however my 2.2 did the same thing on its' last voyage - didn't know better then.
so my questions: do i need to replace a perfectly functioning bosch fuel pump for fear of particles? the see through $2.50 fuel filter should be sufficient, yeah? recommendations to install 2?
any other advice appreciated. thanks!

[GreenT]

Bob - I went through this exact thing for over a year. I couldn't go anywhere without my Weber screwdriver and can of compressed air for blowing out the jets. It got to be like field stripping your rifle in the army, I could do all 6 jets in the dark in about 5 minutes when the backfiring started again. Redoing the tank helped with the fine rust powder. Rebuilding the pump was probably not necessary in hindsight. Replaced/cleaned lines, took the carbs apart several times to clean them, etc. All of these helped to one degree or another. I also was running the clear type filter so I could see what I was catching. I thought the paper element would catch most anything, but apparently they don't. After I stopped getting the powdered rust from the lines/tank I started looking at each jet with a good magnifying glass each time I started backfiring. What I saw were little translucent flakes that would stick in the jets. I don't know if its a byproduct of our local gas or what, but I had cleaned everything so often on the output side of the filter I didn't see any way it could varnish coming loose, so concluded it must be getting past the visible filter. About then Weber came out with new billet filters with screens that filter down to a few microns without restriction. Not cheap, but very nicely made. I figured, who could make a better filter for filtering Webers than Weber? And they work. I haven't carried my can of air for about six months now. Pictures at the place I got it from:

http://www.redlineweber.com/SEMA2002...el_filters.htm

Actually I got two, both the billet and small cannister type. I put in the billet and still have the cannister one unopened. If you are hot to trot and want to get everything done this weekend instead of waiting for a delivery, you can pick up this extra that I have. The billet one is cooler looking though........

[911pcars]

Redline describes two filters: Billet and canister type. They describe them both as effective. However, one costs maybe $30 (WAG) and the other maybe $5. I'm not sure what my point is; an extra $25?

These are nice though:

Sherwood

[GreenT]

I sprung for the billet type because I wasn't convinced my misery was over yet and you can take it apart and clean it and see what's inside. Not cheap, but worth it to me to finally end a really aggravating problem - list on the billet is $101, Redlines price is $60. List on the smaller cannister type is $22, Redlines price is $15.

[bob tilton]

project completed this afternoon thanks to john and his "spare" filter. hopefully this resolved my clogged jets! thanks john!

[ttweed]

project completed this afternoon thanks to john and his "spare" filter. hopefully this resolved my clogged jets! thanks john!

Bob-
Are you using the stock air filter cannister still? If your problem persists, check it out carefully. The inner baffles can rust and send particles into the intake.
TT

[Zeke]

Contamination can be in the carbs themselves. This may or may not be Bob's problem, but it sounds like GreenT's situation. I know this one well as after I had broken in a new motor and then taken the car to the track, adding race gas for the first time that day, I seized the pistons due to a leaning out of the idle circuits (which supply the fuel to the motor at all but WOT conditions). When I pulled the jets, the same transluscent flakes were present suggesting disolved varnish from deep withing the carbs, probably behind the lead plugs that I didn't pull when cleaning.

A very expensive mistake.

[bob tilton]

i am running the K&N weber rainshields so no rust there. i have heard about the problem you describe which is why i guess they later switched to plastic.

to look at the old gas tank through the sending unit hole it looked clean and rust free. once pulled and drained i could hear the "silt" as i moved the tank. there was some minute rust particles and not much else. overall the tank was clean - no varnish layer.

however, i wanted this to be a one afternoon project (pull and replace) which is why i bought another tank and had it boiled/sealed. so far so good but only mileage will tell. unfortunately i have a very short 2 mile commute. i should know within the next 50 miles.