weber 38/mech fuel pump issues

[brian]

anybody seen any issues with a weber 38 coupled with the oem mech fuel pump?
i'm chasing a gremlin that seems fuel related.
it would appear that the fuel pump can not keep up with demand when i'm in flog it mode. above 2800ish rpm with the pedal pretty far into it, it feels like it lays down , then starts bucking. must be under load and well into it to show it's self. any rpm possible underload if i nurse it up.
i've already replaced a pump with unknown milage and age, that displayed simular issues as now. the problem had seemed to disappear with the new pump. current pump is only in service a few months, maybe close to a thousand miles or so. the problem reappeared suddenly and does not seem to be getting any worse, as before.
the 2nd pump was not toyota, and had been in my 'stock' for several years prior to use, but was un-used. i have another that's going on tomorrow.
complete desmog.

 

[JohnnyC]

i run a $15 electric fuel pump from napa....works great...make a block off plate for the oem fuel pump...and i set my fuel regulator at ....i think 4?

 

[mep1811]

weber 38

I have a weber 38 and the stock fuel pump. No problems. What size main jets are you running?

 

[JohnnyC]

how long have you had the carb on?

sound like float problem...need foat bowl more full...its draining the bowl...you are using stock jets?

 

[grant5127]

The mechanical pump produces a pulse action flow and creates turbulence in the float bowl...Webers protest that.....the in-line regulator calms the fuel flow.....most are happy with a setting around #3..........

 

[brian]

carb has been on 6months atleast.
the carb came from man-a-free 8 years ago. was listed as a ''fj60 carb'' and jetted there for............so i have no clue what jets are in it, short of looking myself.

i have a w38 on a 40 with an oem pump, and no issues.

 

[grant5127]

You must have fuel delivery problem.....the Weber has a fine screen/filter in it as well, checked that??

 

[JohnnyC]

just checked my regulator is at #3 also...


has the carb been sitting for that long (7.5 years) new in box ....or....was it on another truck?

if it was on another rig...was it ever cleaned out?

you may have a piece of crud in there...or...accelorator pump sticking? is it sanppy when you snap the throddle or does it bog down?

 

[brian]

NIB
plenty of snap

 

[JohnnyC]

I would go then with the easy 1st try:

as grant5127 says

The mechanical pump produces a pulse action flow and creates turbulence in the float bowl...Webers protest that.....the in-line regulator calms the fuel flow.....most are happy with a setting around #3..........

fuel regulator....you can pick them up at most autoparts store...even if it doesnt fix it its good to have anyway...but it sound like it should fix it.

 

[REKCUT]

I run a 38 with OEM fuel pump and no problem.

 

[brian]

new pump refixed the problem...agian.
i'm going to order a proper oem pump for stock.

 

[JohnnyC]

new pump refixed the problem...agian.
i'm going to order a proper oem pump for stock.

were are you getting these pumps that keep failing? we might want to stay away from that manufaturer

are they tiawan? china? company name?

 

[brian]

the first came from man-a-fre.
the onw on now is from advanced auto....south korea

 

[REKCUT]

I would guess tha something in your set-up is causing the pump to go bad. I think you are fixing the symptom instead of the cause. Just a guess

 

[JohnnyC]

I would guess tha something in your set-up is causing the pump to go bad. I think you are fixing the symptom instead of the cause. Just a guess

Brian: is your fuel filter before or after the fuel pump?

 

[brian]

before

the tank was just down the other year, it's like new inside, when a new fuel pick was installed. a new filter was installed shortly there after as pm.
there is an insulator between the pump and the block.
i'm calling the last pump a fluke. we'll see what happenss once this pump gets some time on it.