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chevyman10

Need Some Carb Help

17 years ago

I acquired another '69 Caprice to go with the one that I bought 4 years ago. I rescued it out of this guy's barn a little over 2 years ago and haven't done anything with it until last week. So it has sat quite a while. Last week I put some fresh gas in it (tank was dry), check the oil, and tried to start it. It fired on the first try and died. On the third try, it fired and ran for a good 10 seconds and died. That is the longest I have been able to keep it running. Today I took the float bowl off to clean it out. It was full of trash. After I cleaned it out and put it back together, I installed a new fuel line and filter. None of these things have helped matters any. The longest that it ran today was about 2-3 seconds. Some times it doesn't even fire. I pulled the spark plug, and it was damp so I know it is getting fuel. Maybe the carb. internals a plugged because I did not clean the float bowl before trying to start it last week? If anyone has any ideas that could help me out, I would greatly appreciate it. I know very little about engine/carb. maintenance. Tomorrow afternoon I am going to pick up another spark plug and see if that might help some. Thanks in advance for any help.

Tim

Comments (7)

  • 17 years ago

    First: Post engine make, numbers (on the engine shroud, Model, type, and code, if present. The name Caprice conjures up a vision of an ancient Chevrolet car, with six or eight cylinders, and which evidently are not related to this post! Please tell us what make of mower, tractor, etc, angine make, etc.
    That said, i'd think a Checy Caprice would be overkill in the lawn mowing action, although, it would mean getting done quickly! At the expense of many fragile plants, hedges, and garden plants, as seeing what you are running over would not be possible, what with the surrounding body parts!

  • 17 years ago

    Ha ha rustyj. Who are you to be calling a Caprice "ancient"? Heck, the oldest Caprice is younger than you (or me). Harrr! While the machine in question (and even that specific carb) are "off topic" for this forum, we do discuss the generalities of carburetion here. Having said that I will offer this. For a carb of that circa , and having sat unused for "quite some time", it should have been taken apart and "dunked" in a carb bucket cleaner followed by probing and blowing out of all jets and passages, before trying to "see" if it would run. Anyhow, chevyman10, you have not made the situation any worse, it will still reqire a complete cleanout and rebuild. Carbs of that size and genre have "accelerator pumps" that operate to "shoot" a pulse of gas into the carb throat every time the accelerator pedal is pushed. Without the accelerator pump working, it is hard to keep the engine running while trying to increase the RPM because when the throttle plates open quickly, the mixture gets leaned out faster than the main jet system can react. The accelerator pump overcomes this by squirting some fuel into the throat as soon as the pedal is pushed. This small burst of additional fuel is only a "pulse" as the accelerator pump is a diaphragm type and only gives one pulse per cycle of the accelerator linkage. But that is just one possiblilty of what problems you have on this old carb. Take the carb to someone that still knows "old timey carbs" and let them look into it (if you ain't comfy with the idea). Some of that grit and stuff in the bowl has been carried into the jets and other places. Also, if you are trying to run the engine using the mechanical, diaphragm type fuel OEM pump.....that pump might just barely be moving any fuel. Realistically, chevyman10, you should try to find websites that cater to "old Chevy" owners (or "Old" chevy owners) to get the best results. Good luck sir.

  • 17 years ago

    Sorry that I did not include information about the mower and engine in my previous post. I know better than to do that sort of thing. It is a Huffy Caprice 32" cut lawn tractor with the original 7 hp Briggs single cylinder engine. I don't have the engine codes handy, but the engine was built in 1968, while the tractor is a 1969 model. During the short time that I can get this thing to run, it sounds good and does not smoke. I'll get the exact #'s off the engine tomorrow. Thanks!

  • 17 years ago

    Wow rustyj, give me another piece of that crow and pass me the humble pie too.

  • 17 years ago

    Well, Mownie, the guy sort of led us to believe he was talking about his Caprice car that he evidently owns, or not, but not a lawn mower engine. His tale sounded fishy, but since he didn't specifically say it was lawn related, i assumed, as you did, that he was talking about a Chevy Caprice automobile engine!
    Only in his last letter did he identify the machine! And, being relativly new to this game, and not knowing all of the lawn mower types and name designations, i just naturally assumed an automobile type!
    Oh, well, Mownie, at least you didn't diss this old guy who is trying to make a little spending money, and trying to impart a bit of help to some of the uninitiated. Thanks for the help, and kind words!
    Rusty Jones
    I couldn't catch the crow, as my plastic owl has them all jittery and they won't come near, and i don't have the recipe for that pie! RJ

  • 17 years ago

    You're alright rustyj. I can't believe you have never eaten "humble pie".

  • 17 years ago

    Your are getting fire to the plug right? Spark plug changes are overrated on small gas engines, if there not cracked all you need to do is clean and check the gap on 95% of them. I ran the same spark plugs in my 34 year old tiller for 15 years.

    Those briggs carb. are easy to clean, most of the time you don't even need a carb. kit if the gaskets don't get torn when dissassembling it. Take it apart clean out all the passages and the inlet screen on the bottom of the stand pipe tubes, note how many turns the air mixture needle is for assemble.

    Remove the head scrape all the carbon off the top of the piston, head, valves, and head gasket (make sure the piston is in the UP position and the valves closed when scraping or all the carbon will end up at the bottom of the bore and make scratch the cylinder walls when you fire it up) use spray carb. cleaner and s stiff wire brush or wire wheel on a drill. wash out between the piston and cylinder wall real good with the pressurized carb. cleaner utilizing the red nozzle provided on the can.

    Make sure you read the instruction and cautions on the can. you don't want to get it in your eyes, breath it, on on you skin. Protect yourself reassemble it and it will probably take care of 99% of your problems.

    IMO this information holds true on any type of carb. from the 69 guadrajet on the sbc, to a ford quadrajet on a 429SCJ ( and YES Ford did put quadrajets on thunderjets 385 series engines) to weedeater, and small gas engines. carb. get gummed up and dirt gets logged in the passages. As the guy on Bonnie and Clyde said "dirt, I just blew it away"

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