No Power on high end

grbeasley

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Feb 9, 2011
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I have a 1994 Mercury Tracker 40hp motor that I just had work done on because I could not get it started after sitting the past 6 months. I have never had any problems so I figured the carb was clogged. The mechanic said the carb (or carbs) did not look too bad but he found a cracked and leaking choke tube, which he replaced. He cranked it in front of me and it ran great. I took it to the river and it started promptly and I idled out of the no wake zone. I gave it throttle and it just gained a few more rpm. No power at high speed like it is bogged down. I can put it in neutral and it revs up fine, but under load....nothing. I am taking it back, but any suggestions as to what it could be? Do these motors have low speed and high speed jets in the carbs like they used to? Thanks
 

alldodge

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Check your fuel supply and lines. Other then that the timing might be off
 

grbeasley

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Feb 9, 2011
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OK, problem solved. Mechanic said a pin came out of the link between the two carbs, preventing high end from kicking in. In laymen's terms, that means he did not put it back together right when he took it apart the first time.

That raises another question. I asked the mechanic if each carb served two cylinders each, or did they both serve all four cylinders with one being low speed and the other being high speed. He said they both serve two cylinders each, but the problem would indicate otherwise. Should I find another mechanic?
 

alldodge

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Everyone makes mistakes and for him to admit it I would give him the benefit this time. If it keeps happening then look for another. In most cases the carbs only feed a given number of cylinders, not like a car with a six pack (3 - 2 barrel carbs)
 

flyingscott

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Apr 8, 2014
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Your mechanic is right each each carb serves 2 cylinders. Inside each carb is a high and low speed circuit for those 2 cylinders. When the pin fell out it unlinked the carbs so that one carb opened and one stayed closed.. You had 2 cylinders trying to to accelerate and 2 cyl trying to idle so you were running on half the motor. All the cylinders need to be running the same for full power and for that to happen the carbs need to be synced with each other.
 
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