purpose of switch

[old swabbie]

90 hp 2 stroke yamaha (I believe 2002) won't keep running and was hard to start. Noticed a red switch right of the middle carb stating : on, off and emergency. Put it on emergency and the motor starts just fine. What is the swith for and what should I do. Thanks

 

[zzzzz]

Re: purpose of switch

that is called a starter...it enrichens the fuel/air mix...actually what you are doing it sounds like is flooding the carbs...sounds like your carbs need some attention

 

[old swabbie]

Re: purpose of switch

that is called a starter...it enrichens the fuel/air mix...actually what you are doing it sounds like is flooding the carbs...sounds like your carbs need some attention

Thanks for the reply. May be impossible to determine, but do you thing anykind of carb clean spray when the motor is running might help?

 

[JUSTINTIME]

Re: purpose of switch

pull carbs and clean is the only way

 

[zzzzz]

Re: purpose of switch

there's a very potent carb cleaner made by BRP called Engine Tuner...you could give it a try...run the motor on a hose with the airbox off...give each carb a 4 to 5 second shot in the throat-keep your hand on the linkage to rev and keep motor running-this stuff REALLY p*sses 'em off !...do that to each carb 4 or 5 times and the last time you do it give 'em enough to kill the motor...cover it up and let it soak overnight...next day have a new set of plugs ready but try and start and run it on old plugs 'cause its gonna' smoke like heck 'til it burns the stuff out of the cylinders...if that doesn't clean the carbs then you're going to have a real carb job

 

[JUSTINTIME]

Re: purpose of switch

that just de-carbs the cylinders
that will not clean the carbs internals

 

[old swabbie]

Re: purpose of switch

there's a very potent carb cleaner made by BRP called Engine Tuner...you could give it a try...run the motor on a hose with the airbox off...give each carb a 4 to 5 second shot in the throat-keep your hand on the linkage to rev and keep motor running-this stuff REALLY p*sses 'em off !...do that to each carb 4 or 5 times and the last time you do it give 'em enough to kill the motor...cover it up and let it soak overnight...next day have a new set of plugs ready but try and start and run it on old plugs 'cause its gonna' smoke like heck 'til it burns the stuff out of the cylinders...if that doesn't clean the carbs then you're going to have a real carb job

Thanks Again, I'll try that. Should the starter switch currently on EMERGENCY ,be ON or OFF?

 

[Dunaruna]

Re: purpose of switch

The enrichment system is automatic. Normally, the switch should be off. The only reason to turn it on is if the enrichment system is not doing it's job correctly. You need to find out why it is not working, the first step is to rebuild the carbs and enrichment pump (the square plate on the side of the middle carb).

 

[old swabbie]

Re: purpose of switch

that just de-carbs the cylinders
that will not clean the carbs internals

I'm now convinced that I must clean my carbs. Do I just need the gaskets ? Also, someone mentioned a "manometer " is required after cleaning. What is this? Will I do better to take it to a shop or is this difficult? My skill level is taking my lawnmower carb apart and putting it back together (successfully).The lake level is dropping and my boat is in the water and I hope I can get it running before it bottoms for the winter. Thanks

 

[Dunaruna]

Re: purpose of switch

Yes, you need the gasket kit (AKA, carb kit), it also contains the needle & seat and a few other vital consumables.