Poor power on hill climb

Hmmm...try another step down in jet and see if it works a low altitude? Also you need to think about power valve, as trouble is at full throttle and power valve is open then...adding what amounts to extra jet. Maybe, just maybe, later tip in for the PV will help...smaller number on its vac rating. Don't know the Merc carb at all well...
 
First: Thank you all for the hints...the apparent winner is ruptured diaphragm in the vacuum advance...it looks like I have been working with only the mechanical....easily fixed with a new one....low rps up the hill = no power!
 
That's likely your fix right there.

The tea pot carbs had a vacuum actuator that opened the little power valve or power jet as they called it. I checked the parts catalogs and all the 885 types used the same power jet reguardless of the altitude but the actuator or piston & stem assembly had two different springs . They show an overlap on these actuators from 49 thru 51 but the early one is 8CM and the later one is 1CM. This may have changed for the Merc-O-Matic but I'm not sure. The later open top carb in 52, only lists one piston & stem actuator assembly and it is different since it had to add a diaphragm to the inner top of the float chamber for it to work. The catalog I'm looking at is for 1952 so they may have added one for 53 but I don't know for sure.

Bottom line is that it may not be possible to change the power jet or actuator if no other sizes or types are available.
 
Rotorwrench:

I have only found 52's in the Teapot's I have taken apart...
 

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Merc Cruzer said:
First: Thank you all for the hints...the apparent winner is ruptured diaphragm in the vacuum advance...it looks like I have been working with only the mechanical....easily fixed with a new one....low rps up the hill = no power!
Click to expand...

I dont think the 53 Merc unit has any mechanical advance and used only vacuum on the load a matic distributor.
Does your have mechanical advance ???:eek:
 
It would be interesting to check out some information that was published by Holley for the old tea pots to see what it might have for altitude changes if any. I've seen some booklets on them and the Holley Load-A-Matic systems but I never thought to grab any up yet. They might have some useful info if a guy wants to stay stock with the old flatty powered beasts.

If a fellow goes non-stock with an old Chrysler or Chevy distributor, Bubba would be one of the guys to talk with about it.
 
I have a selecttion of Merc PV i'll see if any have diff #'s on them than 52. Also have some actuator rods with the spring on them dont think they have #'s on them. Question which way would the #'s go smaller # smaller holes or the other way around???? ken ct.
 
First thing of course is to get a good diaphragm and road test. You MY find that good diaphragm gives you more zip at part throttle but still fails to help when you need to go full throttle...but hope for the best.
Good philosophical point within this discussion...one that all of us probably continually learn and forget...don't look into carburetor till you have checked out the ignition, both for sparking and for advance!
 
Good news the new diaphragm is great as to power....I also changed the springs on the distributor to a little weaker, the ones in there were way too stiff and would not allow for full advance...need to get it on a Sun machine to check the curve.

Kent CT:
On the PV, the jet numbers go down to go leaner so I would guess the PV numbers would follow suit.
 
I think if you have to get into PV to tune your system, you likely need to look at vac level of opening rather than its size. If you are running near full throttle at an altitude where you are already too rich, you don't want any additional feed from PV...but you will still need that enrichment back in the flatlands. Delicate balancing act on opening vac.
 
You would assume so BUT you never know,it could be the other way around. All mine read 52 also. ken ct.
 
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