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  1. #1
    sdlvx's Avatar
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    What did I do to my pro 785

    I was out today for the first time on my 98 Pro 785 and it was running pretty good. I ended up racing someone at WOT for about a half a mile and it started to bog. Some old gas was in the tank so I figured I was just getting some of the crappy gas out. I nursed it a little and it started running fine again.

    Later on, I was beating on it a little more, and I had a major loss of power. I limped it in about half a mile and looked under the seat. Nothing seem too hot or anything. I pulled the plugs and the front two plugs were wet and white (I put new plugs in today). I went to turn it over and it slowly cranked. The exhuast port valves looked kind of stuck open too.

    So I went back to the house and put it on the charger. It took 4 amps for about 5 minutes and then dropped to 2 amps and started turning over just fine. I fired it up and it sounded like it was running well. Disconnected the battery charger and now it cranks fine.

    I ran it for a few seconds and the plugs were still wet and white. So I pulled the plugs again and held my thumb over the plug holes and cranked it to see if anything seemed off. It seems like compression was alright, but I"m going to check it tomorrow hopefully if I can borrow a compression tester from my mechanic friend.

    I had an old loaner battery in there I just charged up today. I checked spark too and it seemed kind of weak when it was turning over weak, but once it started turning over better the spark got a lot better.

    Oddly too, I couldn't get the engine to turn over when I went to get it going today. I figured the starter was stuck or something after the battery stopped drawing a lot of amps so I tapped it with a screwdriver handle to loosen it up and it started turning over.

    So, am I having problems because this battery is shit? Is there a charging problem? Did I blow up my front two cylinders? I have no idea, it's getting gas and it looks like it's getting spark most of the time. The two problem cylinders are the front and the middle. I have wisecos in all three cylinders, but (I know this is probably going to make a lot of people cringe) the real cylinder is sleeved and the front two are not.


  2. #2
    Click avatar for tech links/info, donation request K447's Avatar
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    Running a Pro 785 with old fuel will make people cringe.

    Bad battery and old fuel, and running it hard. Doesn't seem like a good approach, somehow...

  3. #3
    porschemaniac's Avatar
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    First thing check compression with a gauge. Almost sounds like you seized a cylinder and then it cooled off and loosened up

  4. #4
    sdlvx's Avatar
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    Quote Originally Posted by K447 View Post
    Running a Pro 785 with old fuel will make people cringe.

    Bad battery and old fuel, and running it hard. Doesn't seem like a good approach, somehow...
    Well there was maybe a gallon or so tops of old fuel. I just threw a good 7 or 8 gallons into it of fresh premium. I guess if no one has any ideas I'll pick up my battery tomorrow and see if that fixes it.

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