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Old 06-07-2007, 10:27 AM
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brian0605 brian0605 is offline
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you more than likely have a stuck valve.I used to work for a marina in mobile Alabama and we used to see this this time of year. Remove the valve cover (pretty easy on that eng). turn it over by hand and see which valves aren't moving. This is pretty common. Now for the repair, as long as the pistons and valves haven't gotten together and had a party you can use a few different methods to try and free it up. you say it will run right?? Well with the engine running and the breather off of the carb either pour in a quart(in order of my personal preference) 1) marvel mystery oil 2) automatic transmission fluid 3) "Sea foam" fuel additive. Start pouring it in fairly slowly and keep the rpm's around 2000 2500. (It's gonna smoke like a chimney.) When you get about halfway through the bottle start pouring it in faster, The engine may even die. That's O.K. as long as you get most of it down the carb. Now let it sit for a day or two. After a couple of days remove and clean the plugs you might even want to just go ahead and change them. With the plugs out spin the engine over (you may want to lay an old towel or pc of card board over the open spark plug holes to catch the spray of fluid). Now in the past I have just put the new plugs in and cranked it up and run the engine and within a few minutes of running the valves would start to move again and it would smooth out. If it won't free up you can remove the valve cover again and loosen the rocker arm and move it out of the way. You can either use a block of wood or a plastic deadblow hammer and gently tap the stuck valves down further and turn the engine over by hand and work the valves until all are free. reinstall the rockers and valve cover fire it up and see how it does.The reason this usually happens is most people just run some clean water through the foot and engine and pull the tarp over the boat for the winter. Well in a marine engine it is very important to either go out and run the engine for 30 min a month or remove the breather and slowly pour a pint bottle of marvel mystery oil down the carb while it's running and shut it off as soon as all of it is in. Then pull the tarp over it. you might have to remove the plugs at the beginning of the boating season and clean them,but I have found that they will usually crank just fine with out having to pull them. Hope this helps. BTW I have also done this with old cars that have sat up for a very long time too.Marvel Mystery oil ROCKS just ask an old timer!!!! Brian
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