hard to start when warm

[CaptainZ55]

Re: hard to start when warm

Just replaced the impeller on stern drive water pump and noticed a lot of carbon or soot all through the exhaust portion of the sterndrive. So whatever is causing the hard starts when warm is also causing a lot of soot. Could this be a further symptom of the choke not opening or is there something else I should be looking at?

Any thoughts or feedback would be appreciated.

 

[westportfish]

Re: hard to start when warm

It honestly sounds like your well plugs are leaking and causing a rich (flooded) start. Its hard to look down the carb and see them leak as the fuel just seeps out. This is a VERY common problem with Rochester carbs.

This is a common problem on Quadrajets. I will always seal both primary and secondary main well plugs with marinetex on all carb rebuilds marine or automotive.

 

[deves3000gt]

Re: hard to start when warm

i had the dame problem with my carb. i couldnt figure out why the chock would be backon after warmed up. it turned out that the metal cover over the choke spring was not on all the way and as the coil heated up it would turn the choke off and *** it kept getting warmer would pull the choke bake on. that cover stops the spring from going to far. fixed the cover and havent had a problem yet.

 

[RichRab]

Re: hard to start when warm

It has been years since I worked on cars but this jarred my memory, I do not remember what motor but there was a passage in the intake manifold that is supposed to heat up when the motor is warm heating the spring and shortening it to disable the choke when the motor is warmed up. Carbon would build up and clog it. You have to pull the manifold to correct it, a pretty big job. When the motor is cool and you open the throttle the choke should close all the way. The vacuum line is connected to a choke pull off that if the hose is removed (With motor off) and the linkage is pushed in and you put your finger over the hole it should stay in. Alot of times people spray them with carb clnr. and they get ruined. I don't think this is your problem. The spot where your choke spring sits in the manifold should be hot enough to probably burn your hand with a warm engine. I would bet yours is as cool as can be not allowing the spring to get hot. Carefully touch it to see if the manifold is hot. I think you will need the choke to start ad you can put a hand choke on if need be. If this is the case the motor is flooding and probably alot of black smoke is coming out when started.

 

[deves3000gt]

Re: hard to start when warm

I agree with needing the choke i have heard a lot of people say and tell me to just take off the choke plate and give it an extra pump or two. i had noting but bad luck with that the best thing i did was get my choke working right.

 

[RichRab]

Re: hard to start when warm

When the metal of the carb is cold the gas does not properly vaporize. The choke compensates for that.

 

[CaptainZ55]

Re: hard to start when warm

When I rebuilt the carb last winter I checked the solder on the bottom of the wells and they looked ok but not sure that means that are not seeping. The position of the choke spring is different than the one on the boat, it sits higher which should open the choke sooner. The one on the boat when cold connects with the linkage at the base of the spring while the new one is at about 3:00 (vs 6:00. I will change the thermostat and put on the new choke this weekend and will check the heat on the manifold under the choke. If this does not fix it then I guess it is pull the carb. Is there any way to test or check the well plugs and can I put marinetex over the solder as preventive?


Thanks

 

[CaptainZ55]

Re: hard to start when warm

FIXED! It was the choke "stove", the center pivot pin looked tight but could move. It had rotated down and was pulling the choke on all the time. New stove and it works great. Thanks for all your posts - it really helped.

If anyone wants a picture let me know.

 

[figak]

Re: hard to start when warm

Can you post some pictures? I think i am having the same problem, but i don't know my way around carbs. Thanks.

 

[CaptainZ55]

Re: hard to start when warm

will take a few days to get back to the boat for pics - the divorced choke sits on the left side of the carb. and is covered by a metal shroud. It is essentially a bi-metal coil that expands as it warms and this causes the linkage bar that is attached to move vertically and change the position of the choke plate. In my case the center pin of the coil which is pressed in the casting could rotate and this caused the coil to keep the plate closed as if the engine was cold and the choke should be fully applied. http://store.wpsracing.com/ch1932193519.html this is not the exact choke but almost identical (it may fit) but notice the pin in the center of the casting, it is pressed in and it can loosen over years and the choke will not be positioned correctly - too much or too little. both hard starts