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50hp Merc bogs under load

ndyeti

New member
"This is an 85 50hp Merc 4 cyl

"This is an 85 50hp Merc 4 cylinder 2 stroke, Serial Number: 06590197 Model Number: 1050625. It starts and runs fantastic in barrel and water muffs but when it is in the lake it bogs down when giving it throttle. It starts and trolls great in the lake but just will not get above trolling speed. So far I have replaced the spark plugs, fuel filter, fuel line and bulb and gas tank with new. That did not work. I took it to a local marine repair shop and he said my switch box was bad causing number two cylinder not to fire, he installed a new switch box, lowered idle, put it on the dyno, ran it in a tank and said it was running awesome and I should have no problems. Well took it to the lake and the problem is still there. Starts great, revs up in neutral till the cows come home, put in gear give it gas and for a split second it sounds like it wants to take off, like it should, but then it just bogs down to a high trolling speed. At times it has run full throttle just fine but it only lasts for a few minutes, when it is at full speed it will slowly decelerate to a fast troll.
When engine is cold and I squeeze the bulb I can see gas dripping from the top carb back by the linkage that connects to the bottom carb. Also the tri connect for the fuel line that goes into each carb is very wet. Could any of this be my problem?
Also the battery cables are both slightly corroded and I’m not sure how good the battery is, it looks old.
I’m a first time boat owner, just got it this spring and have had this same problem all summer so any help would be much appreciated.

Your Pal,
North Dakota Yeti"
 
"A good start would be to rebu

"A good start would be to rebuild the carbs and since this is new to you, rebuild the fuel pump too. Kits are cheap. Get the battery cables cleaned up and tight. If corrosion is at the base of the lugs, replace them. Also if the motor has sat for some time, it is a good idea to replace the impeller and lower unit oil. Get a manual for it if you don't have one. It will pay for itself in no time."
 
sounds a lot like what my moto

sounds a lot like what my motor was doing . do get the manual a must have . I also did everthing you have done. I had a bad stator
gary
 
"Thanks guys, Just hand the ca

"Thanks guys, Just hand the carbs and fuel pumps rebuilt, mechanic said there was all kinds of crap in the lower carb, and one fuel pump put together incorrectly. Taking out this weekend and keeping fingers crossed, still might be able to salvage some fishing.

ndyeti"
 
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