Float gauge for Holly 1901 carb

[Merc Cruzer]

I am currently running 54's, as they are supposed to be appropriate for 5,000-10,000 ft. Most of the car shows and cruses are in Denver - 5,280 ft. Coming home from Denver involves a 13 mile section that you climb over 3,000 ft. I have jet sizes down to 49, if I need them.

I am really hoping that correcting the flooding issue, that I have confirmed, will solve the issue. Snow for the next three days.

You are right, modern EFI, is a great advantage in our daily cars (Jeep and Mini Cooper).

I read other postings about compression after a new build. Altitude makes a big difference. What most would consider a worn out engine, is the compression for a new rebuild at this altitude.

[Merc Cruzer]

Originally Posted by scicala

I didn't realize you were at that high of an altitude. You may have to reduce the main jet as much as about 4 or 5 sizes because of the thin air. A trial an error thing. One advantage of modern EFI systems.


Sal

Sal,

I am assuming that the idle tubes and the well tubes (attached picture top left and right) are one size only for this carburetor, since they are not marked with a size.

Should the main jets and the power valve (attached picture - lower) all be the same size? I note that I am currently running 54 main jets yet the power valve is a 52.

I note that there were carbs for the Canadian market. The "M" carb I would guess was to show it was for the Mercury in 52'-53'.

[51 MERC-CT]

Wouldn't it be nice to adapt an 'aircraft' carburetor just for your situation.

[scicala]

"Sal,

I am assuming that the idle tubes and the well tubes (attached picture top left and right) are one size only for this carburetor, since they are not marked with a size.

Should the main jets and the power valve (attached picture - lower) all be the same size? I note that I am currently running 54 main jets yet the power valve is a 52.

I note that there were carbs for the Canadian market. The "M" carb I would guess was to show it was for the Mercury in 52'-53'."


Roy, I'm not sure if the main well tubes or idle jet tubes (with threads on them) are all the same size, but the manual calls for #54 idle tubes. Don't think that means .054". The well tubes are actually air bleeds for the main system.
Main jets are not always the same size, but your carb for sea level originally came with #56 main jets, so you may have to go smaller than #54's.
The power valve (#52) has two .037" side holes.
The "M" at the end of the carb part number isn't for Mercury. It's just the latest alphabetical rotation of revisions for the carb. (Before it, was the "L").


Sal

[Merc Cruzer]

I always try to provide a followup after correcting an issue.

The flooding issued is now resolved, with the correct setting of the floats. I had a chance to take it out this morning for a 20 mile run. It seemed smoother, more powerful and did run a bit cooler. The cooler water temp, might have been simply due to the ambient temperature during the run was 49 degrees.

I am now dealing with a new issue: a slight hesitation when accelerating from a stop, but nothing big.

I have to give her credit, I had the heater on, but not the fan and it was more than comfortable. Remember mine is a convertible and they leak cold air something terrible.

My question now, is, sicne the car has been running rich for a considerable period of time, I would guess the engine is quite carboned up. How long should it take to clean out the carbon?

My worst plug has always been # 6. Attached picture is of plugs # 2 (on left) and #6 (on right)