Yamaha 55 problem

[goof01698]

Hi there, this is my first time posting a question so here goes.<br />I have recently bought a old yamaha 55hp ser No L303190 (or C, I cant read the last digit)<br />The engine ran fine for the first 40 minutes and then started to run at maybe 30% power. It eventually conked out but started again no problem. It still only runs at 30% however. I have noticed that it will rev up no problem but as soon as it goes in gear it goes all sluggish again and will eventually conk out. Any suggestions gratefully recieved. Cheers

 

[bossee]

Re: Yamaha 55 problem

What happen if you pump on the fuel bulb at the same time it goes sluggish? If that helps You have probably a bad fuel pump that can not deliver fuel in reguired flow. Then replace the rubber set in the fuel pump. It is probably a fuel pump "rebuild kit" You need then.<br />Could also be the carburators that needs cleaning (and a "repair kit").<br /><br />If the impeller service status is unknown it is wise to buy a new impeller kit also. Impeller should be changed in 2-3 year intervalls as a rule of thumb.

 

[goof01698]

Re: Yamaha 55 problem

wow thanks for the quick reply. I tried the fuel bulb and when I pump it the engine seems to flood. I have also checked the spark plugs after trying again to get it to run properly and the bottom one is wet. Cheers

 

[Ray Neudecker]

Re: Yamaha 55 problem

Time to take a timing light and check for fire. CDI failures on one cylinder are not uncommon on these engines. Problem can also be a fuel delivery one. Relace the wet plug,likely to be fouled.

 

[goof01698]

Re: Yamaha 55 problem

Thanks I will try again with it this weekend