Choke Not Closing Itself... Rough cold start.

[egleas84]

I have the thermal choke on my 83 Mercruiser 120 Rochester carb. The last 3 times I started it was very difficult to get turned over. I started poking around at this and noticed the choke was all the way open even after a few days of sitting.

Is the same spring that warms this thing up and opens it when cold supposed to close it too? Any advice? I haven't tried adjusting the spring thing yet.

If I close the choke manually it starts OK. Runs and idles as good as it can get for a 28 year old engine.

 

[Don S]

Re: Choke Not Closing Itself... Rough cold start.

Is the same spring that warms this thing up and opens it when cold supposed to close it too?

Yes, but, there are different types of chokes. Can you post a picture of your choke setup?

 

[Bondo]

Re: Choke Not Closing Itself... Rough cold start.

and noticed the choke was all the way open even after a few days of sitting.

Ayuh,... Usually,...

It takes a full throttle action to Wot once to set the choke, when cold...

 

[egleas84]

Re: Choke Not Closing Itself... Rough cold start.

This picture is after sitting for 5 days without touching anything. Still wide open from my last cruise.

I closed it manually then turned the key on and waited and it does open itself. I turned it back off and waited several minutes and it did indeed shut itself... The difference is the engine is cold this time and the battery is still on (i usualy cut power to the whole boat when I'm done). Not sure what to think now. Theories?

 

[dubs283]

Re: Choke Not Closing Itself... Rough cold start.

This picture is after sitting for 5 days without touching anything. Not sure what to think now. Theories?

yes,

follow bondos advice from post #3

one pump of the throttle to WOT and then check the choke plate, betcha it closed

 

[egleas84]

Re: Choke Not Closing Itself... Rough cold start.

Am I supposed to pump to WOT before starting to set (close) the choke?

 

[egleas84]

Re: Choke Not Closing Itself... Rough cold start.

yes,

follow bondos advice from post #3

one pump of the throttle to WOT and then check the choke plate, betcha it closed

I'd stayed closed. If I open it manually wot closes it.

 

[dubs283]

Re: Choke Not Closing Itself... Rough cold start.

Am I supposed to pump to WOT before starting to set (close) the choke?

yes

if you look at the choke cam and see the idle adjustment screw pinned against it, you will see why the choke plate is held open and when pumping the throttle releases the screw against the cam allowing the plate to close

just try it and you will see

 

[egleas84]

Re: Choke Not Closing Itself... Rough cold start.

That explains the rough starting... I suppose pumping some gas in there would help it fire faster.

It used to work without doing that; this all started when I adjusted my idle screw (was too high). Silly me. I haven't had this IO very long.

 

[Don S]

Re: Choke Not Closing Itself... Rough cold start.

That explains the rough starting... I suppose pumping some gas in there would help it fire faster.

Being a young guy, You have probably never run an engine with a carb and a choke before have you? They take a bit of work and getting used to when starting cold. They do not start and run like your EFI car or truck does.

Here are some starting procedures from a Mercruiser owners manual.

 

[egleas84]

Re: Choke Not Closing Itself... Rough cold start.

Being a young guy, You have probably never run an engine with a carb and a choke before have you? They take a bit of work and getting used to when starting cold. They do not start and run like your EFI car or truck does.

Here are some starting procedures from a Mercruiser owners manual.

I had an Evinrude outboard for 5 years; much different! The choke was the manual 'push the key in' type. And I have a '74 MGB, also with manual choke... So yes and no; this is my first carbed engine that has a choke that operates in this manner.

I do like easy solutions and like to learn though; all I have to do is pump the throttle to WOT once and I off I go.

Thanks!

 

[Pete104]

Re: Choke Not Closing Itself... Rough cold start.

Youngest guy in the world to be introduced to an "automatic" choke.

 

[egleas84]

Re: Choke Not Closing Itself... Rough cold start.

Youngest guy in the world to be introduced to an "automatic" choke.

I doubt that. I'm sure there are some kids in a highscool automotive class that know more than I do about it.

 

[mkast]

Re: Choke Not Closing Itself... Rough cold start.

I'm sure there are some kids in a highscool automotive class that know more than I do about it.

High school automotive classes no longer teach carburetors.

 

[Don S]

Re: Choke Not Closing Itself... Rough cold start.

High school automotive classes no longer teach carburetors.

I had to laugh when I read that. I remember a few years ago when I lived in Alaska, we hired in a guy that just got out of marine tech school in Fla, he was a good mechanic, then one day we had a Merc 470 come in for a tuneup (I lucked out and got the job) he stopped by the boat and wanted to look in the distributor. He had never seen points before, and I had to explain how they worked, the dwell meter the whole thing.
"Stone knives and hammers" is the comment he made, or something like that.

 

[rick3452]

Re: Choke Not Closing Itself... Rough cold start.

Being a young guy, You have probably never run an engine with a carb and a choke before have you? They take a bit of work and getting used to when starting cold. They do not start and run like your EFI car or truck does.

Here are some starting procedures from a Mercruiser owners manual.

I assume that this does not apply to TKS?

 

[Don S]

Re: Choke Not Closing Itself... Rough cold start.

I assume that this does not apply to TKS?

I feel sorry for anyone that has one of those things.

 

[rick3452]

Re: Choke Not Closing Itself... Rough cold start.

So would it be possible to relace TKS with another type carb?

0m012817

 

[Pete104]

Re: Choke Not Closing Itself... Rough cold start.

You don't have to replace it. Just pump the throttle! Have you tried that? If you don't use the TKS almost everyday, it is complete waste.
What exactly is "your complaint"? Just curious.