symptoms of a clogged carb

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,306
usually we read threads here about what is going wrong and then the repliers try to offer solutions as to what the problem could be...

seeing as i now I have a few larger and more expensive motors, I want to be more aware of potential problems.

so on an other wise normally running motor, when a carb starts to show signs of a clog or not working properly...what will be the tell tale signs, or symptoms?

on a v4 all spark is great, all compression is great , fuel delivery is great to the carbs,....we cant see inside to verify that the correct amount of fuel is getting to one cylinder..

whats the motor doing?

not idleing right?
not showing full WOT?
are we gonna show an over heat in one head?
will we HEAR it running poorly?

not how to trouble shoot it..just whats the symptom(s) thats somethings wrong


just talking about the effect of ONLY a carb starting to clog or being clogged

kind of a reverse problem, question

thanks

bob
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: symptoms of a clogged carb

Symptoms that point to carb issues are sometimes subtle and sometimes very obvious. But here are a few:

1) Poor idle quality
2) Poor transition from idle to midrange rpm
3) Hard starting
4) One or more plugs show a lean condition (a reason to check them often).
5) Lack of high end power
6) Poor hole shot
7) Missing on one or more cylinders due to lack of fuel
8) Surging which may be due to improper float level settings or vacuum leaks

The thing most people ignore is just generally poor operation yet they continue to run the engine. Lean fuel mixture ruins an engine because with no fuel, it also gets no lubrication. No lubrication scuffs cylinder walls and pistons and they seize.
 

TOHATSU GURU

Admiral
Joined
Jul 22, 2004
Messages
6,164
Re: symptoms of a clogged carb

9) Fuel flowing like a fountain out of the carb ports.
10) Pulling the drain screw from the bottom of the carb and having no fuel come out.
 

bob johnson

Rear Admiral
Joined
Feb 25, 2009
Messages
4,306
Re: symptoms of a clogged carb

would a cylinder head show a high temp, or even throw an alarm if one of the cylinders isnt getting enough gas and oil???

will the friction be enough to over heat that head?????

just wondering if there will be any other tell tales, besides to poor running condition.
many people might try to feel out a poorly running motor...going out and fiddleing and trying a few different things and then going back out on the water... ect...all the while making more damage...

I took my 70 apart and I know i dont ever want to take the 115 apart!!!

looks way more complicated...

bob
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: symptoms of a clogged carb

Keep in mind that the carburetors are synchronized to the ignition timing. Therefore if that is screwed up you can destroy and engine due to detonation. Yes, lean can cause overheat but you would have lots of other issues before that and they would have to have been ignored.
 
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