Bogging at low idle.....carb issue?

jonny rotten

Petty Officer 1st Class
Joined
Jan 8, 2012
Messages
345
4.3 2 bbl electric choke
On muffs
Stays running at higher RPM's and sounds fairly smooth
At idle it stalls when cold BUT if I close the butterfly to almost closed it revs up. I can sorta control the RPM's with the butterfly.
Seems to stay running better at idle when warm but still not good enough that I trust it enough to test in the water

I thought it could be choke issue
The choke closes all the way when cold when I pump the throttle to reset it .
Does that mean the electronic choke is working correctly?
I "think" it opens to full open almost immediately on a 75 degree day but I'll watch it next time.

Cleaned inline filter at carb
New fuel pump last week
New water separator
Cap and rotor look pretty much new

Thought I might have bad gas from last year so I disconnected the fuel line at the water separator and filled up a water bottle and it sucks up the gas almost to quick so it's getting plenty of gas. It runs the same as with the old gas

Could it be a vacuum leak somewhere?
I thought I read with electronic choke vacuum leaks won't have an effect but could be wrong?
Was working fine when I put it away last year so it makes sense in 6 months the gas gummed the carb enough to effect the running condition but still run. Ran seafoam in it last year before putting it away but maybe not enough?
Anything I can do or check before a carb rebuild that I'd rather not do in the middle of the summer.....but will if I need to ASAP to get in the water
 
Last edited:

Bondo

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Ayuh,.... It's my guess that the carb's idle circuit is plugged or restricted,.....

Rebuild the carb,....
 

utfisherman

Seaman
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Mar 15, 2011
Messages
58
Having about the same problem mine is a 120 hp 4 cyl. I rebuilt the carb new cap and rotor and points. When mine idles I get black soot coming out. It idles on muffs but on the lake it bogs down and dies. Help
 

jonny rotten

Petty Officer 1st Class
Joined
Jan 8, 2012
Messages
345
Could use some help ASAP.
No gas getting to bowl after rebuild
I rebuild the entire carb yesterday for 7 straight hours. I followed a Youtube video with the same carb EXACTLY as I did it.

It's on the boat
When I crank it it wouldn't start. Plenty of gas getting to carb. Tested and gas shot across the boat
Pulled the gas line at the carb and when I loosened the nut the gas shot back under pressure. Screen in correctly
I pulled the top of the carb still attached to the boat and the bowl is bone dry after cranking many times

What is my problem?
Will the float being out of adjustment stop ALL gas from getting to the bowl?
I bent the tab a little bringing the float up higher because the video said I should be level and wasn't. I should have let it as it was because it was working fine. Could that be my issue? The pin is now all the way closed?
Anything else it could be?
 
Last edited:

Rick Stephens

Admiral
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Aug 13, 2013
Messages
6,118
Float height is probably the most important adjustment on a rebuild.... in fact, usually a rebuild is making sure all the passageways are open and then setting float height and double triple checking it. If the float height is not right it can easily prevent gas from getting into the bowl. That's its purpose.
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
Having about the same problem mine is a 120 hp 4 cyl. I rebuilt the carb new cap and rotor and points. When mine idles I get black soot coming out. It idles on muffs but on the lake it bogs down and dies. Help
Happy to help, but you should start your own post and not hijack someone else's with your problem.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,958
It's on the boat
When I crank it it wouldn't start. Plenty of gas getting to carb. Tested and gas shot across the boat
Pulled the gas line at the carb and when I loosened the nut the gas shot back under pressure. Screen in correctly
I pulled the top of the carb still attached to the boat and the bowl is bone dry after cranking many times

What is my problem?

Ayuh,..... The only thing it could be is the needle, 'n seat,....
It's opens, 'n closes by the action of the float,.....
 

jonny rotten

Petty Officer 1st Class
Joined
Jan 8, 2012
Messages
345
Thanks for the replies.
Took the carb back off ripped it apart and adjust the float to the MM. Then checked 5 more times.

Fired right up and purrin like a kitten

On a side note, Anyone watching Mike's Carb rebuild video on YouTube, When he's adjusting the float and says " forget what what the paper says, just make the float level, I've been doing it that way for years".........DON"T do that or you'll be ripping it all apart and doing it twice. Do go by the paper measurements
 

nola mike

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Apr 22, 2009
Messages
5,366
On a side note, Anyone watching Mike's Carb rebuild video on YouTube, When he's adjusting the float and says " forget what what the paper says, just make the float level, I've been doing it that way for years".........DON"T do that or you'll be ripping it all apart and doing it twice. Do go by the paper measurements
That's pretty much good advice for anything on the interwebs. Yeah, there are some/many tricks to everything, but at the end of the day go by what the manual says if there's any doubt. Also, it's good practice (for me at least) to make sure your float and needle are doing what they should be before putting any carb back on the boat/bike/lawnmower/chainsaw.
 
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