Carb Question - Rebuild or Replace?

[tomelenbaas]

I have opted against EFI conversion due in part to some of the feedback I got to an earlier post. Thanks to those who rang in.

Now the question is what to do with my Holley 4160. It's original to the boat ('88 Mariah, 351 PCM). The last time I had it serviced was at least 10 years ago so I know it's long overdue. My question is this - is there any reason to replace it with a new carb rather than service and rebuild it? Are the present day 4160's any different than they were 25 years ago? My engine is stock, the only thing I have done is to replace the points with an electronic ignition.

[wotan2525]

As far as I know, these carbs have not changed. You could send it off and have it professionally rebuilt and it would be like-new. No reason to replace if it isn't broken.

[rludtke]

A new replacement 4160 is more than $500. Professionally overhauled carberators will be returned to original drawing specification but will cost on the order of $250. An overhaul kit that you instal will cost $50 or less.

Whats the difference? Well, the new replacement and the pro overhauled carbs arre functionally identical, just one has all new parts, and the other has some new and some refurbished used parts. If you overhaul yourself, you will be replacing most of the parts that wear from normal use. The kit replaces the important fuel metering parts. The remianing parts that wear over time but do not meter fuel are the throttle valve shafts and bushings. If the wear beatween the shafts and bushings is to great, unmeasured air can leak through, causing a lean mixture. The shafts and bushings can be purchased and replaced if you are so inclined- it is a simple task. Otherwise, you will probably find that the overhaul kit will dramatically improve your carbs performance. The micro-abrasives present in the fuel causes wear to these sensitive parts which over time affects the carbs performance. Because of this, you should overhaul periodically as a part of routine maintenance. Depending upon usage, I would suggest on the order of every 2-3 years.

There are two ways to aproach the kit intallation: 1) Just remove the bowls and swap parts, and 2) Remove carb from engine, completely tear down the carb and thouroghly clean, and replace parts. Either route will probably result in noticable improvement.

So my recomendation: try the cheapest route first (the overhaul kit), and see if you are happy with the results.

By the way, the Holley 4160 features an inlet screen to filter the fuel. This will not catch the tiny micron sized particales that wear out the carb. Neither will the fuel/water seperator. Consider installing a 5-micron in-line fuel filter downstream from your pump. This will add notable life to your carberator.

[scottchapin]

Doing my carburetor myself today, I'll let you know if it is more difficult than it sounds. Check out the pictures I posted showing how bad it was when I took the carb off.
Scott

[scottchapin]

Check out the post I just did. Carb wasn't too hard.