1979 50HP mercury stalls on idle

[Cyrez]

Hi all,<br /><br />I've just bought me a 50hp mercury blueband and it seems to run fine.<br />After boating a while at full speed etc. the motor seems to idle very rough and sometimes even stall, when it stalls it is very difficult to get it running again.<br />I noticed that there are no air filters on the carburators, is this normal or should they be there? can this also has something todo with the idle problem?<br />When i tested the motor on shore it ran fine in idle but it seems to give problems when it have run at high speed.<br /><br />Any ideas on this?<br /><br />Thanks<br />Marc van Buuren

 

[12Footer]

Re: 1979 50HP mercury stalls on idle

To answer the air filter question, no. Your outboard was made without a filter. Outside of a black cage-like structure (boaters nicknamed the "wasp-catcher"), that's it.<br /><br />Your motor probly just needs a tune-up. You know, plugs, carb clean,decarbon reeds,ect.<br />And possably an adjustment of the throttle cable (your is double cable i think).<br />If you are maechanicly-inclined, order the shop manual,and have a go at the tune up in your garage.<br />Good luck.<br />One more hint 4-week old gas/oil mix is approaching "stale", so keep the fuel fresh as possable.

 

[Cyrez]

Re: 1979 50HP mercury stalls on idle

Hi 12footer,<br /><br />Thanks for the reply.<br /><br />I've did everything you said already except for the decarbon reeds, due to the fact that english is not my native language, can you explain what you mean with that?<br /><br />And you suggest that i have to tighten the throttle cable so that idle is a bit higher then it is right now?<br />(yes, i have to cable's)<br /><br />Thanks.<br />Marc.

 

[12Footer]

Re: 1979 50HP mercury stalls on idle

It's not just the reeds,Cyrez.<br />All 2cycle motors get a charcoal-like deposit over all surfaces inside the engine. <br />This carbon gets under the rings and expand them. The stuff holds heat,further increasing temps in combustion chamber. I have also seen it plug up the exaust ports,and an otherwise fine motor would not run above a labored idle....It couldn't breathe.<br />There are additives available at the marina and boat shop that will keep this stuff from getting the upper-hand on your motor. But I prefer to use the aresol cleaners (also available at boat stores). And I "decarb" them 2 times a year, or after 40hours operation.<br />Sorry about the American slang words. (like "decarb").

 

[12Footer]

Re: 1979 50HP mercury stalls on idle

aresol= aerosol in the above post (spray can)