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1973 merc 500 4stroke carb settings.

K

keen fisherman

New member
Hi all. Got a 73 merc 500. Played around with my carb settings, and found my bottom carb idling screw half a turn less than top carb. Is this correct? What should the right settings be? Also, after turning of the motor, it stats easily, but dies on acceleration. What could cause this? P.S. Cant find allot of help on older mercs here in South Africa!!!!!!!
 
If it dies on acceleration it may well be too lean on the low speed mixture.--------Put them both at a turn and a half from lightly seated and try again. There is no " magic setting " from a book, you have to start with an initial setting and try adjusting it to get best results.---------I am sure you meant 4 cylinder motor , not 4 stroke.
 
Thanx for the info. Will sure try.

My top carb leaks from a tiny hole in the body of the carb when i prime my fuel bulb to much. heard this can be as result of incorrect float setting. Can this be true?
 
You can easily run a carb over by pumping it too much, that is normal. You're pumping it till the float closes and forcing fuel out the overflow.
 
A float valve is stuck and not closing off when you are manually pumping the fuel.-----------Time to have a look at the carburetors and it is fairly simple work.-----------Don't want to tackle it ?----------If fuel system is not reliable / clean and properly adjusted , then you risk ruining the motor.
 
Must tackle it, but dont wanna get into a situation where i cant find spares that might be needed. Anything i should be aware of when stripping and assembling?
 
Use ordinary automotive carb cleaner w/a spray nozzle to get into the tiny openings. Blow out all of the fuel circuits w/100 PSI compressed air.
 
Great!!!!!
Think im going to try the automotive carb cleaner first, and c if there is any improvement, before i take of the carbs.
It can work cant it?
 
Hi Guys.

Had the boat on the water this w/end, after i cleaned and set the carbs.
Wow!!!! what a great improvement. Didnt battle whit the motor once!

Thanks to all u guys for suggestions and help.

Have a great one.
 
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