Difficulty keeping engine idle when cold

rperla

Seaman
Joined
May 21, 2005
Messages
62
When starting the engine, I have to keep revving it up and down o keep the engine running. It will go to 1800 rpm and down to almost 0. If I keep increasing rpm up and down slightly it will eventually stay at an idle of about 900-1200. Hard to keep at a lower idle. This is a 4.3 volvo penta 1993. Could it be the choke or other linkage? I just had the carburetor rebuilt and replaced the fuel pump too. Any ideas appreciated.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,944
Engines do take a bit of time to warm up, and the choke also takes some time to come off. As for the rebuilding of the carb, only the guy who put it back together knows what he checked/adjusted on it. You need to get the service manual for your engine, then find out what carbs is on it. And I mean, the carb's, Part#.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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47,297
my guess is the choke isnt set

however if you have to keep moving the throttle to keep it running, your carb is not properly cleaned/rebuilt.
 
Joined
Mar 1, 2005
Messages
923
Not knowing your specific carburetor or the style of choke, it's tough to say. However, I'm with Scott that it sounds like the choke isn't working properly.
 

-JR-

Petty Officer 2nd Class
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Jun 21, 2009
Messages
133
i have the same problem on my AQ 125 ,since my engine does not have a choke ,I normally take a screw driver and turn the low idle stop screw a half a turn. When I am in gear or it is warmed up I will turn it back where it was .
Been doing this for 20 years now.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
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i have the same problem on my AQ 125 ,since my engine does not have a choke ,I normally take a screw driver and turn the low idle stop screw a half a turn. When I am in gear or it is warmed up I will turn it back where it was .
Been doing this for 20 years now.

Dont hijack a thread....not cool

On your motor, fix your carb
 

-JR-

Petty Officer 2nd Class
Joined
Jun 21, 2009
Messages
133
Dont hijack a thread....not cool

On your motor, fix your carb

You are a old grumpy old man ...not hi jacking at all.....Just telling the guy what i do on mine that may work on his .
Might of had the same problem before the carb rebuild.
What forums are all about is getting feed back on the subject.
I think it is you who is doing the hi jacking......10-4
 

QBhoy

Fleet Admiral
Joined
Mar 10, 2016
Messages
8,286
Either that the idle has been adjusted previously to counter a carb problem, choke isn’t working or perhaps even water contaminated fuel or old fuel.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
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Messages
47,297
You are a old grumpy old man ...not hi jacking at all.....Just telling the guy what i do on mine that may work on his .
Might of had the same problem before the carb rebuild.
What forums are all about is getting feed back on the subject.
I think it is you who is doing the hi jacking......10-4

your 125 solex carb has nothing similar to the OP's 4.3 with a holley.

two completely different carburetor technologies.
 
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