Recent content by Casey J Pieretti

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    1976 Johnson 70hp will only run low rpm after warming up.

    Ok, the hose from crankcase was loose.
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    1976 Johnson 70hp will only run low rpm after warming up.

    Rebuilt fuel pump, was not leaking but the bladder was very stretched. The vacuum line was in sorry shape and definitely leaking. Hoping to run this weekend.
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    1976 Johnson 70hp will only run low rpm after warming up.

    Update, rebuilt the fuel pump and found the vacuum line to be very loose and definitely leaking. The diaphram was very stretched and loose. There was no vibration gasket for mounting on the block. Waiting for the wind to die down for a test run.
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    1976 Johnson 70hp will only run low rpm after warming up.

    UPDATE: RE-read the gas tank documents and it is a new west marine tank that vents. I found poorly connected fuel line that was leaking. Waiting for fuel pump kit. Then test run number 4.
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    1976 Johnson 70hp will only run low rpm after warming up.

    I also know it ran well before it was sitting in garage. It was also at altitude in the sierras, sitting dry for two years.
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    1976 Johnson 70hp will only run low rpm after warming up.

    Compression all equal at 120 on one guage and 145 on the other. I have a new plastic tank. No venting. I pumped up carbs and left cap cracked on a 3/4 tank. Good spark, gap is spec. Like I said it runs well for a few minutes than only idles under load. Does not overheat. Shuts down and re-starts...
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    1976 Johnson 70hp will only run low rpm after warming up.

    So I ran with loose cap and had no change. I am now going to rebuild the fuel pump as it is $20 for th kit.
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    1976 Johnson 70hp will only run low rpm after warming up.

    Well, reworked the lines.... same issue upon test run. I did find the pump ball was soft after running. I will next check the fuel pump then move into electrical.
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    1976 Johnson 70hp will only run low rpm after warming up.

    Next update, the three way splitter is too small for the hose. Definitely allowing air onto the fuel system. As well as it being cheap plastic....and my favorite, the zip tie hose clamps!
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    1976 Johnson 70hp will only run low rpm after warming up.

    An update, tok off carb cover housing. Floats are working. All looks clean. Found a hose nightmare, see photo. Pumps up ball and leaks fom every hose. Will check fuel pump next. But I will restate. The motor runs great for several minutes than will only idle while in gear. I can shut it down...
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    1976 Johnson 70hp will only run low rpm after warming up.

    Also, since the motor sat these first 6 gallons are at 40:1. Though I put some oil in the cylinders before turning it over. Compression is great and even. Idles well, starts right up at sea level.
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    1976 Johnson 70hp will only run low rpm after warming up.

    I have no history on motor. Only it sat in a garage for a few years. What gets me is it jumps out of the hole, but after about 3-5 minutes of running at speed it just will not run in gear at anything more than an idle. I can shut it down and let it sit for a few minutes and it will start right...
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    1976 Johnson 70hp will only run low rpm after warming up.

    Hi, Ihave a 1976 70hp. Good compression, good spark and runs like a champ for about 3-5 minutes. Then it will only run at low speed starts just fine, revs in neutral. Fuel ball Ball is hard. Even if it site for a few it will not run at higher speeds. New gas, New gas tank, New fuel lines. I...
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