2gc pump rod adj.?

[ziggy]

hi folks. i'm doing a carb. rebuild. down to putting it back together again. engine listed below. although. the carb. i'm rebuilding is off a 72 250 L6. i don't know if that one is the original carb. carb #7040083. the carb. on my aristocraft does appear to be the correct carb. #7043183. to late now. i used my new parts on the 7040083. the question i have regaurds the pump rod adjustment. should i just bend the pump rod on up to meet the .962" adj. from the top of the pump rod to the top of the airhorn w/throttle plates closed? i'm a 1/4'' short i bet.... or is there some other difference between these two carbs. that i'm not hip to...

 

[ziggy]

Re: 2gc pump rod adj.?

i've been doing a bit of research. interesting for sure... i have sm #2 (the book), c-90-71707 (publication date of pp 4B-8 where pump rod adj. is found is july, 74). i also have 90-71707 286 (pubication date June 76 reviseion 1, pump rod adj. info on pp 4B-9), which is the pdf version of sm #2.

best i see there is a discrepency.

info in the book regaurding pump rod adj. is.... measured from the top of the air horn to top of the pump rod lever, throttle plate fully closed...

info in the pdf. is, measured from the top of the carburator to the top of the pump rod lever, throttle plates closed.....
the specification for distance is the same at .952

i still feel i need to adj. my pump rod, however the pdf. version is very much closer to what i already have for the adj.

so, now, which one is right for what i have? the pdf. version? it is much closer to the adj. i have existing....

 

[JustJason]

Re: 2gc pump rod adj.?

i think you should leave the pump rod alone and install the carb and put it in the water and see how it does.
your not going to know how much or how little you need the accelerator pump to discharge untill the boats actually in the water under a load.
I look at it this way, bending of the rods is a mechanical adjustment that SHOULD have been set when it left the factory (i know... should... ughh) and it still SHOULD be within speck unless it was monkeyed with at one point.

almost every carb has got a hint of a bog to it on accerleration, weather its a rich bog or a lean bog most of them have an ever so slightly one. On some of them if you spend enough time you can get them pretty snappy.
The rochesters are a little togher because it is bending the pump rods or on some models moving the rod into different tabs of the rod end. If you had a holley its a bit easier to really get it dialed in.

 

[ziggy]

Re: 2gc pump rod adj.?

i think you should leave the pump rod alone and install the carb and put it in the water and see how it does.

i think your right.... i did leave it alone and am now ready for a water test.... does ok in the drive on the hose... at least it idles... smoother than it did too. i suppose it could be because i found dwell at 40+*....... it was set at 31* last time i looked (spring). it's now back to 32* + timing set at 6*btdc. idle pretty smooth at 600rpm. need a water test..... thanks cj....

 

[ziggy]

Re: 2gc pump rod adj.?

wow, this thread made it to page 4.... iboats sure is a busy place..... anyways.....sea trial this evening. adj. the idle speed tied up to the public dock. did it by the book best i could... idle at 600 in fwd. do have to make a crisp shift... idle in neutral is 700 round abouts....maybe 650. i'm 3/4 turns out on both mix screws. hope that ain't to lean... one thing that makes me wonder though is. per the instructions. it says initial setting is 1.5 turns out. put in water, put in fwd. disconnect remote, set idle speed screw to 500-600rpm...hum. if i set the speed screw, ain't i opening the throttle plates? with the throttle plates open a bit, don't that make the idle mix screws null and void? they did seem to have some effect. but not as much as with the plates closed..... though idle was to low with the throttle plates closed. anyways. in fwd. i'm doing 600 rpm on a shop tach. sob leaps out of the water under a full throttle smash. my buddy was out this evening too. trying out his new 19P ss prop on his brand new '08 195, 220hp fuelie stingray.... he didn't seem to want to try a hole shot on me... his top end is way beyond me, but i think i could do him for a hole shot.... . i got no back fire, no hesitation. no nothing other than real smooth... i'm happy i think.....

on iniaial inspection, i still have a minor black smoke bath tub ring on my transom........ not near as much as it was though.... time will tell.... my compression ain't as happy as i'd like it, perhaps that could be a cause too.....