motor wont open up

jasondees

Cadet
Joined
Oct 19, 2014
Messages
9
not sure of the year model but its on a 1987 pontoon boat. I have a 75 horse mercury when not in the water it does just fine. when in the water it bogs down and wont go full throttle. I put a new fuel line and bulb on it and I have tried pumping the bulb while throttle is up and still no change. the only change I get is when I push the key choke in and it tries to open up till I let off the choke then it goes back to the same way. any help I can get is very ap.
 

WrenchHead

Petty Officer 2nd Class
Joined
Feb 15, 2009
Messages
120
Sounds like you are getting gas to the carb, but the carb is not delivering gas to the engine in sufficient quantity to run an engine under load. When you close the choke the engine pulls more gas (or less air) from the carb and it runs better. Well this is a sign you are sucking air around carb, or the high speed jets are partly clogged, or the float in the carb is set too low.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,033
Stop running the motor and determine what is wrong by testing.----If you have a plugged carburetor you could be starving cylinders of fuel and most important starving them of oil.------Damage could result.-----Clean and inspect the carburetors.
 

jasondees

Cadet
Joined
Oct 19, 2014
Messages
9
It's a 1986 model motor. Going to take the carbs off after work today and will let u know what's up and once again thinks for all your help
 

jasondees

Cadet
Joined
Oct 19, 2014
Messages
9
I pulled the carbs off and cleaned them and pulled the spark plugs out and the top 3 had burnt stuff on them and the 4th plug was still shiny is that a bad sign
 

jasondees

Cadet
Joined
Oct 19, 2014
Messages
9
Ok got it all put back together and all plugs are firing now I just got to get it to the water and check it out and see what happens
 

jasondees

Cadet
Joined
Oct 19, 2014
Messages
9
Still haven't got to take it to the water and check it out yet but my step dad said it might be a cracked coil causing it would a cracked coil cause it to do that even with it trying to pick up with the chock on?
 
Top