Fuelproblem, mercury 4cyl 80 hp -79

deikoo

Recruit
Joined
Jul 12, 2013
Messages
3
Hi,

I have a problem with my Mercury thunderbolt 80 hp from 1979.
The problem is that it only fires at 3 cylinders out of 4. ( cyl 3 doesnt fire up)
We have changed the sparkplugs, we have checked the spark, we have checked the fuelfilter.

I have remove the air silencer to the carbs ( 2 of them) and when we pump the handpump on the fuelline, the top carb will flow over and the bottom carb dosent happens anything with.
We removed the bottom screws for the carbs and from the top one, it came a lot of fuel, from the bottom carb, bearly nothing.

Can it be that the bottom carb doesnt get enough of fuel so the top of the bottom two cyl doesnt fire up?

Please forgive me for my bad english, but Im from Sweden :)
 

Luckymann77

Seaman Apprentice
Joined
May 23, 2011
Messages
35
Re: Fuelproblem, mercury 4cyl 80 hp -79

Sounds like the float on the bad carb is stuck.
Either the float sticking or the needle on the float sticking.

God Bless,
Luckymann77
 

deikoo

Recruit
Joined
Jul 12, 2013
Messages
3
Re: Fuelproblem, mercury 4cyl 80 hp -79

Sounds like the float on the bad carb is stuck.
Either the float sticking or the needle on the float sticking.

God Bless,
Luckymann77

Thanks for your answer!
Do you think that this can be the problem for not fire up on the third cylinder?

Today we have checked the ignitioncables, stator and the trigger. Everything shows correct values. I wanted to check this so I can forget ignitionproblems.
 
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