v4 xFlow mains partially clogged? how do you drain the carbs?

[pcrussell50]

short version:
'77 115 starts and idles fine, won't rev past about 1800 rpm under load. not overheating since warning and overheat system and buzzer test good.

my latest v4 crossflow hadn't been run since early summer, 2009 when the previous owner discovered cars and got a girlfriend and didn't use it again. fast forward to mid-august, 2010... i am the new owner. when it came time to fire it up in my driveway on the muffs, i took a chance and used the year old fuel that was already in the tank. it started pretty easily and idled pretty well. i goosed it a few times, and it spun up nicely, but i didn't want to press my luck with a runaway since i was on muffs in my driveway. so i called it good, and towed her out to the wife's grandparents place out in the desert on the colorado river. and sure enough, once i get past the "no wake" zone and power up to get on plane, she falls over at 1800 rpm or so, and dies if i open the throttle too far.

my _guess_ as to the problem: the way the carbs are designed, the little idle orifices drain clear when not in use, so they almost never block up with bad gas. BUT the bigger mains can clog or partially clog, allowing enough fuel up to the idle circuits, while still being too clogged up to flow enough when the throttle is fully opened and high power is needed.

IF that is true, can i just remove and clean the main jets without removing and rebuilding the whole carburetor? i hear that removing the main jets is how you drain the carbs anyway... so i figure i could remove them and clean them without disassembling the whole carb and link'n'syncing again and all that.

any other ideas, suggestions?

-peter

 

[emdsapmgr]

Re: v4 xFlow mains partially clogged? how do you drain the carbs?

The two screw plugs on the carb bowls do double duty. They will drain the carbs and they also provide access to the main (high speed) jets. You do need a special screwdriver to get to these jets to remove them and visually check them. The even make a special short factory tool to remove them while the carbs are still on the engine. It is really difficult to say that visually checking/cleaning the jets will solve your problem. You may just want to pull the carbs off, completely disassemble, and use some aerosol carb cleaner to blow out all the passages. Visually check everything. Pulling the jets out is but part of the cleaning-you need to make sure there is no dried fuel in the carb passageways, too-and that requires complete disassembly.