2Slow4me

will only pull max rpm in neutral, or trimmed way up, but with any load, just bogs and backfires

fuel filter on inlet has been removed and inspected, was clean. still...no luck

2Slow4me

mine is stock which i think is a rochester, would it a similar design?

2Slow4me

carb is stock and full rebuild 2 years ago with new accelerator pump.

stock, i thick rochester, can the jets be checked without taking the carb off?

MILD THUNDER

iTrader: (3)

Make sure the choke isnt stuck closed. I'd make sure secondary butterflies on the carbs are opening.

Not exactly sure on the marine rochestors, but on automotive ones, if the choke is closed, the secondaries will not open.

Rexx

Might consider pulling the valve covers if it is not a fuel problem. Let the motor idle (do not rev it or oil will go everywhere). Then check to see all your rockers are moving the same while idling. If one or more don't, you ate a cam lobe. This happened to me a few years ago and the engine behavior was just as you described. You won't necessarily find play in the pushrods since a wiped off lobe can be down to the base circle.

fireboatpilot

+1 on check the timing advance rate. Use a fuel pressure gauge to check pressure while under a load. Doesn't sound like anything mechanical to me but what do I know? I'm always learning. My guess is the timing isn't advancing quick enough under a load or it's not getting enough fuel. Drain your fuel filters into a clear glass container and see what settles. One crappy load of fuel will take forever to work it's way thru. Just my 2cts.

2Slow4me

How do I check for the timing advance rate?

Carbs are off now, and dropping them by the carb place for a quick check (it was rebuilt 2 years ago)

I have two tanks, feeding into one Y (no valve) drained the filters about 3 times now, looks perfect, nothing in it, nothing floating, nothing at the bottom.


Have freinds that use the same gas station, and they have no problems (so doubt it would be bad gas)

2Slow4me

This is a reply from Scream and Fly:

Sounds like a fuel restriction or air leak into the fuel system or a bad fuel pump. Put a vacxuum gauge and clear hose on the fuel line where it ataches to the motor and a pressure gauge at the carb. Rub the boay under load and observe the gauges. Vacuum should read 3 - 5 inches, any less and air bubbles in the clear hose indicate an air leak such as a broken pickup, cut or loose hose. High vacuum will indicate a restriction such as a clogged pickup, clogged anti-siphon valve, collapsed hose or clogged fuel tank vent. Fuel pressure should be 6 - 9 psi. Normal vacuum and low pressure indicates a bad fuel pump. High pressure indicates a clogged filter in the carb..

2Slow4me

Dropped by the carb place that rebuilt it to check the carb, and they told me "the secondarys can't get plugged because the fuel first has to go throught the primarys before the secondarys and the primarys are much smaller"

That makes no sence to me, (or does it??)

I plan to open it up and take a peak. (after I buy the torx to open it up)

Do I need a new top gasket for a Rochester Quadra jet? (was rebuilt 2 years ago, with very few running hours on it)

2Slow4me

fixed! very strange a little spring that keeps the secondary flap closed had a littlw worn notch in it.

and that was stopping the secondary carb to open.

lubed the spring up, and reduced the spring tension

works great now. now that i know that caused the problem, i'll dremal the spring notch or get replace the spring.

i think the carb rebuilder who rebuilt it 2 years ago should have noticed the wear and replaced it (probaly a $2.00 part, and i spent 3 weekends and about $300 in parts....frustrating

but its working now

thank you to everyone that helped out with idea and suggestions greatly appreciated