carb issue with choke

[imraan47]

So i cant seem to start the boat lately and i opened the carb to see the choke plate sits open at cold.
once i close the choke plate by hand the boat will fire on single start. if i then shut it off and try to start again it just wont start or is hard to start...i just pull shifer out and press gas then try to turn engine on. well if i just go back and close the choke plate then it will fire.
so whats causing this choke thing to act like this.
need to fix this issue.

thanks

1988 merc 120hp 2.5L

 

[Bondo]

Re: carb issue with choke

Ayuh,.... Most automatic chokes require atleast 1 full throttle stroke to Wot, to actuate...

Most carbed motors need alittle throttle action to start,...
It Ain't an Efi...

 

[mpdive]

Re: carb issue with choke

Either your choke coil thermostatic spring has taken a dump or someone has turned the coil. Where is the index mark at now?

 

[imraan47]

Re: carb issue with choke

Either your choke coil thermostatic spring has taken a dump or someone has turned the coil. Where is the index mark at now?

well it used to fire up right after priming it..2 times if cold.

not sure what you are talking about with index mark lol. can you explain.
on second thought i will take a picture of the carb and where the spring is tomorrow and post up

 

[mpdive]

Re: carb issue with choke

Use to fire up..... indicates a closed choke for rich condition starting....As it should be. Wide open choke at cold start is a lean condition. There are index marks on the coil which are usually preset at the factory and can be considered widely innacurate as far as settings go. The same two boats shipped out of the factory, one going to N. Dakota and one going to Palm Beach Florida, will have different starting characteristics due to different climates. First thing to do is turn the key on and verify 12 volts to the choke coil. Turn the key back off. If you do then loosen the three choke coil screws and turn the housing until the butterfly just closes. retighten the screws and verify the butterfly opens during warmup. Choke coils do go bad. It is nothing more than a thermostatic spring, and they do lose tension over the years. I still suspect that if it is wide open on a cold engine, someone has already turned the housing for unknown reasons. Your coil and choke system is a little different than a car due to the lack of a fast idle cam. The operator is responsible for running a cold engine at increased rpm's during warmup. A car does it on it's own because of the fast idle cam. Boats do not have this cam due to it presenting a safety hazard of the boat going in gear at fast idle. The choke on a boat operates independant of the throttle linkage.

 

[cr2k]

Re: carb issue with choke

Actually the marks are on the cover the round black thing on the side of your carb and there are several little bumps on the housing, Should line up with the center one for normal operation, if you only use in warm weather back off a little if cold weather operation set it a little more clockwise.