could someone help, please

[khannah39]

Recently purchased a boat with an Evinrude motor. Model # 50437M, S/N E0003686. Is this a 1974 and if so what does the M stand for and the 73? Also when I first put the boat in the water it ran perfect. Two weeks later I put it in again and it would start but had no power and would die when I put in gear. Any help would be greatly appreciated. Thanks in advance.

 

[hunt-fish.com]

Re: could someone help, please

Check your fuel lines. Does the primer buld on the fuel line feel firm and stay firm when pumped up? If not you may have an air leak. Check the gas tank for air leaks also. Hope this helps.

 

[Joe Reeves]

Re: could someone help, please

Khannah39..... You transposed the "73" in that model number to "37". Model #50473 is a 1974 50hp Evinrude. Whatever the "M" stands for has escaped me. The problem may simply be a fouled spark plug. However, you'll need to trouble shoot the engine as follows.<br /><br />Remove the spark plugs and note their appearance and which cylinder they came from. Then check the compression which should be 100+ psi and even on all cylinders. Then, with the plugs still removed, check the spark which should jump a 7/16" gap on all cyinders with a strong blue flame.<br /><br />If the above checks out okay, I'd suspect that the engine has a fouled carburetor.<br /><br />The spark plugs should be Champion QL77JC4 or L77JC4 plugs with a gap setting of .040 .

 

[Yepblaze]

Re: could someone help, please

Sounds like it's just being tempramental.<br /><br />Maybe some 2 year old fuel and solids clogging up the works.<br /><br />Maybe some water in the fuel.<br /><br />Maybe an intermittent ignition problem.<br /><br />Maybe just leaky needle/seats in carbs.<br /><br />You could get a manual at the bottom of this page. Read through that. Get it setup with a garbage can under the motor or on those ear muff water things so you can run it on land with the cover removed and check it out for the obvious like loose, or shorted wires. Fuel leaks, or loose parts.<br /><br />For most of us, we would change spark plugs and look carefully at the ones that came out looking for one not as finely colored as the other one or two. <br /><br />Do a compression check while we have the plugs out. Then if the new plugs didn't help we might look for clues to tear through the carbs just to make sure they were perfect.<br /><br /> That is unless it's obviously dropping a cylinder then I'd be more inclined to start doing ignition diagnostics.

 

[khannah39]

Re: could someone help, please

Guys, I really appreciate the responses, and the help, I'm kinda new at this boating thing and am trying to learn. It helps to have nice people answer your questions. I'll try the suggestions you gave and thanks again.