No spark on Merc 85hp

1960 Starflite

Petty Officer 1st Class
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Jun 23, 2011
Messages
355
where does the accelerator pump go? im not sure what you’re referring to.
An automotive carburetor has a linkage driven "Accelerator Pump" which sprays, enriches fuel mixture when pedal is pushed quickly. You won't see this on the Merc because fuel is Vacuum drawn thru the carburetor.
 

ryanmul57

Cadet
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Aug 20, 2023
Messages
25
Well, if the carbs fill, but no fuel will go thru the jets, they are either clogged or do not have adequate air flow thru their throats. The latter would be unusual, if the carb base gaskets are good and the bolts are snug.

If you remove the hex bolts at the base of the bowl, fuel should drip out. That means the mains are clear. or clear enough for now. Next would be to disassemble and clean the idle jet and passages, and rebuild the carbs with gaskets, floats and inlet needle and seats.
That's very odd because I just took them apart and they are totally clean and not clogged or gummed up.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,235
Did you get the idle restrictor tube (idle jet) under the brass plug on the top of the carb? Did you clean the two or three the small holes drilled in the throat? Actually the '73 side bowl carbs also had a brass jet in the carb throat, if memory serves. The banjo filters under the caps on the bowl cover are clean? Crowleymarine has a decent exploded figure of your carb, if you need it. I haven't worked on one of those carbs in a lot of years.
 

ryanmul57

Cadet
Joined
Aug 20, 2023
Messages
25
Did you get the idle restrictor tube (idle jet) under the brass plug on the top of the carb? Did you clean the two or three the small holes drilled in the throat? Actually the '73 side bowl carbs also had a brass jet in the carb throat, if memory serves. The banjo filters under the caps on the bowl cover are clean? Crowleymarine has a decent exploded figure of your carb, if you need it. I haven't worked on one of those carbs in a lot of years.
yes I got the idle restricted jet and the idle mixture needle all out and cleaned with car cleaner and I can spray it into all of the passages very easily and not one is clogged. The weird part is when I take the carbs off and empty them then reattach them they spray at first but once they are filled they stop spraying. Just doesn't make any sense.
 

Chris1956

Supreme Mariner
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Mar 25, 2004
Messages
27,235
The original floats were yellow foam. The alcohol in our fuel tends to dissolve them. Newer floats are hard plastic. They can crack and not function. Make sure the floats and float levers are good and set properly, respectively.
 
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