yamaha 55hp wont start

[Sprint]

Hello I have recently purchased an early 80’s Yamaha 2 stroke 55AE 663 L304629 (numbers on the side) outboard but it wont start. It turns over and sparks, I have checked the carb and jets and they are clean the fuel is also new and running through well. When I try to start the engine it turns over and back fires now and then through the exhaust, but never does more than that. Just wondered if you could help me, as I don’t have much experience with two stoke engines. Thanks<br /><br />Alan

 

[Ray Neudecker]

Re: yamaha 55hp wont start

First check compression. If good and it is firing, spray some fuel directly into carbs while holding throttle open, then if it fires, you have a fuel restriction problem. Be sure the battery is hot, if it does not spin fast enough it will not fire.

 

[JB]

Re: yamaha 55hp wont start

Hi, Alan.<br /><br />Backfiring through the exhaust is evidence of a timing problem.<br /><br />Check the flywheel for a sheared key, and check that all spark plug wires are connected to the correct cylinder.<br /><br />Good luck.

 

[Sprint]

Re: yamaha 55hp wont start

Thanks for the feedback just one quick question what is the best way to cheack the compression is and if the key is sheared or not, I guess that means taking the flywheel off but I just wanted to check. Thanks<br /><br />Alan