PMO Accel Nozzle Cleaning?

[whackit]

Hi Folks,

So I have a set of PMOs that sat for awhile. Car is very difficult to start cold but when it’s going it idles and drives perfectly. Warm restarts are fine. I immediately suspected the accel nozzles/pump. Pulled the air filters and as suspected a few of the nozzles barely squirt (or not at all). My plan is to just pull the carbs and flush out the accel circuits and check diaphragms and clean nozzles. I don’t really think I need a full rebuild since it’s running well also don’t really want to mess with things too much. Spray carb cleaner where I can etc. Blow out etc.

Let me know if you think this is an okay plan and if there’s anything I should do specifically when carbs are off. FYI Tank was drained and fresh fuel. New filters etc already done. Peeped the tank interior and all looks good. I’m not really a carb guy so hoping to keep it simple. Thanks!

[thetorch]

Not hard to clean the nozzles. Test the pumps first to make sure you know how much each is pumping for one full linkage push. Somewhere around 0.6 cc ? -- better check the spec, I don't recall exactly. Use a small test tube to measure, dangling down under the nozzle with a wire.

When done cleaning them out, check again.

I bench test them with rubbing alcohol not gasoline. Much easier.

[1QuickS]

The tip diameter is 0.50mm. Get a drill from MSC Industrial or Amazon.

An insulin syringe is just perfect for checking squirt output.

[stownsen914]

As suggested, test first. Make sure to run the fuel pump first so the float bowls have fuel, and exercise the accel pumps a couple strokes to pump them up.

If the accel pumps are the issue, check the linkages, and consider that the diaphragms/seals could be the cause.

[Gordo2]

I think the acceleration injection nozzles can be removed & cleaned without removing the whole carbs. They come off / out with top plate removal.

I normally try to avoid removing my carbs to avoid resetting the linkage to get a good sync.

[gamin]

I have PMO's on the '70. They are clean and everything works. Car is HARD to start but once started it runs fine. I've had this car for 53 years with zenith's, weber's, and now PMO's. It has always been hard to start cold. These carbs don't have chokes. You have to prime to start. Pump the throttle. Also use the hand throttle for start and warmup. The hand throttle is really important. It is your friend.

[whackit]

Thanks for all the help. I probably should have given a little more detail. I’m aware of how to start the car normally. It started fine for years until it sat for a year with some sketchy gas in it. So it’s not firing up like it used too after the two pump hand throttle routine.

The nozzles are not all squirting. I don’t really know the carbs that well… I’m more of an engine guy… I assume it’s a clogged nozzle but could also be diaphragm, check valves etc. if anyone could give me a decent roadmap for troubleshooting that would be super helpfull!