Re: Force 125 questions...
Welcome to iboats.<br /><br />The impeller is the rubber paddle wheel inside the waterpump. If it fails, and they do as the rubber breaks down, you will overheat the engine. Force motors DO NOT like to be overheated.<br /><br />Props are measured by their diameter, and their pitch.<br />Picth refers to the theoretical distance the prop would travel thru the water when turned one full revolution, given that there was no drag or slippage. So the pitch is measured in inches.<br /><br />A small pitch prop (13) would only travel 13 inches. Since the motor only has to push it thru 13 inches of water, it is easy to do, like driving your car in first gear.<br /><br />With a large pitch prop (23) , the motor has to work harder to push the prop thru 23 inches of water, kind of like trying to start out with your car in third gear.<br /><br />By selecting the correct pitch prop, you can keep the engine in the recommended maximun rpm range at wide open throttle (WOT). A lower pitched prop will allow the engine to turn more rpm. A higher pitch prop will lower the maximum attainable rpm. You don't want to over rev your engine, but you do want to be able to get the rpm up near the maximum recommended rpm. This is done to manage the load that is placed on the engine.<br /><br />You need to have a tach to do this properly.<br />You can get a tach from
www.tinytach.com , call them to order it so you get the right model, about $37.<br /><br />1- buy a repair manual, Seloc or Clymers brand, $35, read it
<br />2- replace the impeller, $15-25, BEFORE you run the motor again <br />3- buy a compression gauge and check the compression<br />4- new sparkplugs<br />5- fresh gas<br />6- check for a strong spark on all plugs<br /><br />If the compression and spark are good, then move on to the fuel pump diaphram and carbs, rebuilding and syncronizing - This is critical as you cannot allow a 2 cycle motor to run lean, or it will burn up.<br /><br />Read these pages:<br /><br />
http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000015 <br /><br />
http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=36;t=000016 <br /><br />
http://www.boat-props.com/prop_info_2.cgi?page=rpm <br /><br />If the engine is in good condition, you should be able to get all these things done, including rebuilding the carbs, for under $200. Then you will know it is right and should be reasonably reliable.<br /><br />You mentuoned 30 mph af full throttle. <br />How big is this boat?<br />Are you using the in boat speedometer or a gps unit?<br />Old boat speedometers are not very accurate.
